Expert: Mars Astronauts Would Lose Teeth

Ant wrote to us with a story on Discovery about the long term consequences of manned and "womanned" missions to Mars - lots of research about bone-weakening effects of zero G environments, with tooth loss high on the list.

Comments

That's not an insurmountable obstacle

[Dancin_Santa]

I've been to the National Air & Space Museum at the Smithsonian. Apparently, you don't need teeth to eat Astronaut Ice Cream and Tang.

Dancin Santa

Re:That's not an insurmountable obstacle

[number one duck]

But how are you going to open bottles and tighten bolts on your way home? Teeth are much more mass/fuel effecient than spanners will ever be...

Oh, I'm sorry, I thought this was a Russian mission at first. Teaches me to not read the article...

Re:That's not an insurmountable obstacle

[Anonymous Coward]

Just send a bunch of hockey players. They all have dental implants anyways.

All I want for christmas is my two front teeth

[xted]

I say we get all the astronauts to smile for a group picture when they land on mars.

Re:All I want for christmas is my two front teeth

[Anonymous Coward]

reminds me of the simpsons episode where Homer gives up his dental plan for a Keg, and there's this guy there with one tooth. God bless the Simpsons!

Re:All I want for christmas is my two front teeth

[SEWilco]

Well, I think that if the astronauts lose all their teeth then they would just suck.

Real Url

[Talez]

URL is wroing... Real URL is:

http://dsc.discovery.com/news/briefs/20010827/ma rs teeth.html

Do people read the bit which says "Check URLS" anymore?

Talez

Re:Real Url

[notext]

I tried to post the real link as well but got so lame compression filter thing, so I figured screw it, if you wanna be that way let them send everyone to the wrong page.

Re:Real Url

[xted]

Why bother? People like you always seem to do a good job pointing it out to everyone.

Re:Real Url

[TheCabal]

Your URL is wrong, dude. Don't you read the bit which says "Check URLS" anymore?

The One True URL is:

http://dsc.discovery.com/news/briefs/20010827/ma rs teeth.html

How's that foot taste?

Re:Real Url

[Skapare]

And yours is also wrong. Didn't you check it, either? That's what [Preview] is for. It works a lot better if you make it into a hyperlink.

Space Food

[q-soe]

Well most space food is in a paste or freeze dried format to boost nutrient intake anyway so it wouldnt matter.

One would thing the issues with blood polling and muscular atrophy may be more succint on long missions like this, there is a dange that muscles can atrophy very badly with long term exposure to low or zero gravity, this coupled with bone fatigue might mean that an astronaut arriving back on earth after his long trip might just collapse when he is exposed to the earths gravity.

Astronaut pancake anyone ?

Re:Space Food

[Hyperbolix]

Well most space food is in a paste or freeze dried format to boost nutrient intake anyway so it wouldnt matter.
Not true. At least not any more. I saw it on the Discovery Wings channel. They actually have crunchy cereal and all that good stuff.
- Hyperbolix

astronauts don't need teeth anyway...

[dR.fuZZo]

Have you seen the stuff they eat from those pouches?

Re:astronauts don't need teeth anyway...

[Arcturax]

So what about when they get back to Earth? How would you like to lose all your teeth? Think about how that would screw up your eating habits here on Earth.

Jesus H. Christ... why don't people THINK before they post?

Re:astronauts don't need teeth anyway...

[dR.fuZZo]

So what about when they get back to Earth?

You mean they're supposed to come back?

Re:astronauts don't need teeth anyway...

[Anonymous Coward]

You honestly thought he was serious? I think your post should be modded up as "funny". Do you make stupid replies like this to every psarchastic joke posted? Man, you look like a tool. Maybe you should have THOUGHT before you posted.

Re:astronauts don't need teeth anyway...

[Arcturax]

What? Still not convinced it would suck to lose some teeth? *holds out closed hand* Come 'ere. Lemme show ya something!

Re:astronauts don't need teeth anyway...

[Arcturax]

Heh good one. Hey I wanna apologize for blowing up at you before. I should have seen it as a joke , but for some reason I read it as blatant disregard for the astronauts who are risking their lives and health to get mankind out into space. Chalk it up to posting too early in the morning.

No hard feelings I hope!

I think the link is broken

[leucadiadude]

It looks like the story link doesn't work. At least it didn't work for me. Here is the one that worked for me.

Beverly Hillbilles

[Anonymous Coward]

I can just imagine a toothless colony of Beverly Hillbilly types 200 years in the future.

Re:Real Url - Still broken, Try this - no space

[hillct]

http://dsc.discovery.com/news/briefs/20010827/mars teeth.html

no loss...

[siegesama]

Not like there's any good restaurants on mars anyway.

Working URL

[mughi]

Here's a working link to the story.

I'm now hit with that 'compression filter' problem.... how to get the info out there seems to be the question.... Ah. good. this ramble fixed it.

Re:Working URL

[IvyMike]

I'm now hit with that 'compression filter' problem.... how to get the info out there seems to be the question.... Ah. good. this ramble fixed it.

Man, that's lame; I'd submit it as a bug. ("My concise, to-the-point post was rejected until I added unneeded verbiage"). The cure is worse than the disease.

Get people from the Backwoods of Arkansas...

[BiggestPOS]

They are already toothless :)

(just joking, its a fine state, I lived through High School there)

No teeth? Good for oral

[Anonymous Coward]

I don't think any astronaut would complain while receiving smooth oral.

Mars is not a zero G environment

[tinrobot]

The discovery page seems dead. But, going out on a limb -- from what I've read, it seems to take about 6 months to get to mars. There have been more than a few people who've lasted this long in space, and they seemed to have nice smiles when they returned.

Once on mars, the effects should be mitigated by the gravitational field - right? How much less is mars' gravity compared to earth?

Re:Mars is not a zero G environment

[Anonymous Coward]

1/6th the gravity of Earth. It's part of the reason Mars doesn't have an Earth-like atmosphere even though the planet's volume is similar to earth.

Re:Mars is not a zero G environment

[mughi]

Read the story. Among other things, a two-year Mars mission including one year of zero-g (6 months there and 6 months back... that back part is also important) would be enough to cause permanent tooth loss.

And the story also mentions those same people you cite.

Re:Mars is not a zero G environment

[Trollificus]

"...would be enough to cause permanent tooth loss."

As opposed to what, temporary tooth loss? ;p~

Re:Mars is not a zero G environment

[mughi]

As opposed to what, temporary tooth loss? ;p~

Good one. But seriously, as opposed to the bone loss:

"But while most astronauts can restrengthen their bones once on terra firma again, their tooth loss...would be permanent"

Re:Mars is not a zero G environment

[Commander Spork]

No, you're thinking of the moon. Mars is closer to 1/3, I believe.

Re:Mars is not a zero G environment

[cavecanem911411]

It's ~38% of Earth's gravity. I read too much sf.

Re:Mars is not a zero G environment

[Anonymous Coward]

So you just rotate the ship fast enough to simulate enough gravity to prevent the tooth loss, and give them extra calcium supplements. What's the big deal?

BTW, does that mean that the cosmonauts who've spent more than a year in orbit are all toothless?

Re:Mars is not a zero G environment

[Anonymous Coward]

You're right. Mars is about 1/3 the mass of Earth while the Moon is 1/6. I got the two switched.

Re:Mars is not a zero G environment

[Dr. Spork]

Read the story. Among other things, a two-year Mars mission including one year of zero-g (6 months there and 6 months back... that back part is also important) would be enough to cause permanent tooth loss.

WTF? Did everyone forget that there have already been MANY people who've spent more time than this in space? Sure, they're all Russian (AFAIK), so maybe their teeth are stronger because they weren't brought up on American junk food. Please, just because you have a slow news day doesn't give you license to have a dumb news day.

Re:Mars is not a zero G environment

[mughi]

WTF? Did everyone forget that there have already been MANY people who've spent more time than this in space?

And that's exactly where the article mentions the information comes from. Those cosmonauts exhibited signs of osteoporosis (Or rather, loss ten times faster than osteoporosis). Combine that with a year of almost 1/3-g between 6 month stints of zero-g, and that on the average the bones of women are less dense than the men to begin with and you end up with an issue that must be considered.

Also, at the moment Valeri Polyakov's record of 14 months in space still stands. Not that much more than 12 months, and he definitely didn't have that extra year of low-g in between.

Re: Bug in Slashdot methinks :P

[Talez]

The space is exactly where the input field broke the URL up onto the next line...

Very perculiar indeed :P

Talez

Gravity == Acceleration?

[Dark Paladin]

Realizing that doing something like this would increase the cost by, well, a lot, couldn't the astronauts accelerate at around .5 to 1 G for half the trip (creating gravity), then reverse the spaceship and decelerate (yes, I can't spell, but neither can the Slashdot staff some days).

You'd need more fuel for this, of course. But it could reduce the problems of microgravity.

Of course, I could be wrong.

Re:Gravity == Acceleration?

[nomadic]

Or just create a cylindrical craft with spin. Of course NASA isn't exactly known for thinking outside the box...

Re:Gravity == Acceleration?

[Meddel]

You're right in that providing artificial gravity is a possibility, but the amount of fuel to accelerate at 9.8 m^2 half way there is huge, and there's not really a reason for doing it like that.

There are two good alternatives, though, which have been tossed around, and have the same effect, though with very little fuel use. One is to send a cylindrical ship, and spin it about it's axis, so that there is a force pushing the astronauts to the outside walls. Like in 2001.

That works, but it creates some weird design problems, as far as headroom and living on the walls.

The other option is to let out a tether with a countermass on the end of it, and then spin around a central point on the tether. With a big enough countermass, or a long enough tether, this works really well, and it's comfortable for the astronauts, as they can stay oriented to the 'floor' of their ship.

There was originally a plan to put something necessary at the other end of the tether, like fuel for the return trip or something, but it turns out to be much more efficient if you can just put something disposable on it (like one of those big boosters you used to leave Earth). That way you can just pop a bolt when you get to Mars, and don't have to worry about the tether snagging when you try to reel it back in.

A book that talks a lot about this is Robert Zubrin's "The Case for Mars". He's the president of the Mars Society, and is pretty knowledgeable about this stuff. I highly recommend the book to anyone interested in some of the design challenges, and why we can beat them.

Re:Gravity == Acceleration?

[Mals]

I'm quite sure that in order to create artificial gravity the force or acceleration would have to be pointed in a downward direction in reference to where the astronaut was standing. I don't think that by accelerating the ship to 9.8 m/s^2 we will be able to create artificial gravity but just a thrust force or that launching feeling. Something similar to what happens when you accelerate hard in a car. Plus the amount of fuel that would be required would be enormous and highly expensive.

But to answer your question, Gravity that we experience on Earth does equal acceleration but it has to be pointed downward or towards the centre of an object to have the same effect that it does on Earth.

Re:Gravity == Acceleration?

[Black Parrot]

> Of course NASA isn't exactly known for thinking outside the box...

Actually, there's a pretty cool idea floating around for sending two craft (one USian and one Russian, IIRC) and tethering them together so that they would rotate around a common center.

Re:Gravity == Acceleration?

[Anonymous Coward]

the force or acceleration would have to be pointed in a downward direction in reference to where the astronaut was standing.

Just orient the astronaut and his furniture based on the ship acceleration, not the other way around, you silly meatball.

Re:Gravity == Acceleration?

[Anonymous Coward]

'I'm quite sure that in order to create artificial gravity the force or acceleration would have to be pointed in a downward direction in reference to where the astronaut was standing.'

There wouldn't be any problem here...you just chage the configuration of the craft to have the 'floor' be in the same direction of the booster (This a correctly dorected Normal Force)

'I don't think that by accelerating the ship to 9.8 m/s^2 we will be able to create artificial gravity but just a thrust force or that launching feeling. Something similar to what happens when you accelerate hard in a car.'

You don't accelerate to 9.8 m/s^2, you constantly accelerate at this rate (For Example: you leave your foot on the gas petal forever; and this 'car' has no top speed...while the speed of light...but thats a different story). Thus since F=ma (with mass being semi-constant...fuel loss and stuff, and a sustained 9.8 m/s^2 acceleration or 1G) you have gravity for your entire trip. (Minus the inital/ending manouvering and the 180 that you would have to pull in the middle of the flight)
It would require so much fuel it wouldn't be practical without fusion, anti-matter, riding lasers, a series of explosions, ion drives, etc... but it COULD be done in this method.
And Centripetal force takes so much less energy to sustain anyway so....

Re:Gravity == Acceleration?

[Anonymous Coward]

I seem to remember from high school physics that rotation creates an acceleration at right angles to the spin also. This would mean that folks in a spinning cylinder would also feel a pull towards one end of the cylinder. I imagine that this would feel quite nauseating when you were walking around.

Re:Gravity == Acceleration?

[odaiwai]

...so if a spacecraft is under 1g acceleration, the back wall will become the floor. When the ship is turned over at the mid point of the journey to decelerate, the floor will now be pointed in the direction of travel and will still be down, as the thrust is still a vector perpendicular to this.

dave "what is this, rocket science?"

Re:Gravity == Acceleration?

[Anonymous Coward]

I seem to remember that you are completely wrong and a fucking moron.

Re:Gravity == Acceleration?

[BombTechnician]

A single cylindrical craft wouldn't cut it (think gyroscope) you would have to have two rotating sections rotating at the same speed in opposite directions to keep the ship from spinng end over en.

Re:Gravity == Acceleration?

[Anonymous Coward]

The thing with a spinning shaft, or anything spinning for that matter, is that then we would have to worry about the corriolus effect. As the astronauts move along in the ships, they would feel a force trying to push then up as well.

Re:Gravity == Acceleration?

[CTho9305]

you misinterpreted that. that is just to keep the math right so everything works out nicely

Re:Gravity == Acceleration?

[Anonymous Coward]

Of course NASA isn't exactly known for thinking outside the box...

Gee, yeah, except when they figured out how to land on the moon. Maybe you should be a NASA scientist? You seem to have all the answers.

Re:Gravity == Acceleration?

[foldedspace]

Why are we NOT doing this now? We have astronauts submitting themselves like guinea pigs every time they go up to the gravity experiments, but why? Don't we have enough data yet? We already know that it is bad for them, their bones and their teeth. Build a station that makes sense. I know I'm not the only person that ever saw the movie "2001: A Space Odyssey" (1968, Clarke, Kubrick). Rotate the puppy. The tether idea isn't new either.

Re:Gravity == Acceleration?

[Anonymous Coward]

We're not doing this now because the #1 reason the taxpayers are willing to pay for the station is the promise of microgravity manufacturing. Of course, one could have rotating hab modules and non-rotating EMs, but that would cost money, and we all know that NASA's mandate is to break physical law with the proceeds from a penny ante poker game.

Re:Gravity == Acceleration?

[esonik]

The other option is to let out a tether with a countermass

How do you accelerate such a construction ? How do you keep alignment for, say communication links back to earth or solar panels ?

...but it turns out to be much more efficient if you can just put something disposable on it

But is it really efficient to carry more or less useless mass to mars ? Who did come to this conclusion (Zubrin?)?

Re:Gravity == Acceleration?

[rcw-home]

Gyroscopes only precess when there is a gravitational force acting unequally on them (for example, when they are supported on only one side).

For example, the artificial horizon gyroscopes in aircraft do not precess.

Re:Gravity == Acceleration?

[TheOnlyCoolTim]

per disciplinum mea lux videbis == Through my discipline you will see the light???

Just testing out my rusty latin skillz....

Tim

Re:Gravity == Acceleration?

[Anonymous Coward]

the promise of microgravity manufacturing

Most of the population doesn' know what microgravity manufacturing is -- except for making zero-g porn flicks

womaned mission and teeth loss, a dream come true!

[Anonymous Coward]

hot-in-the-ass astronaut bitches sucking my dick with no teeth!

What is wrong with Slashdot?

[Anonymous Coward]

IE 6.0 is out. Time to spread the word. Go download it here.

ummm....

[Anonymous Coward]

last i checked, mars had gravity... then again, I haven't been there in a while...

- god

Re:ummm....

[mughi]

last i checked, mars had gravity... then again, I haven't been there in a while...

Yes... but if you read the story you might notice that it mentions a mission with one year of zero-g. That's pretty much 6 months out and then 6 months back.

Re:ummm....

[crayz]

Yeah but:
a) you have gravity in between those two trips for however long you stay on Mars
b) Russian astronauts have done this and kept their teeth

Re:ummm....

[Anonymous Coward]

listen bud, I don't have to read no stinkin article, i'm GOD, for christsakes! i read it before it was even written!

don't make me get biblical on your ass!

- god

Cheaper alternative

[Mdog]

You wouldn't need much fuel at all if you did the 1G radially.

The Mars Cork-Screw...roller coaster or NASA mission: You be the judge.

--
God I wish slashdot had spellcheck

reds on the red planet

[Anonymous Coward]

don't believe me? just look at their propaganda!!! That's right! On the "woman" explorer's (ha!) shoulder you see the rising sun of that goddamn commie facist japan. Those asians won't only collonize mars first, but they'll communize it too! My fellow countrymen, you disgusting canadians, and any of you frogs who don't piss yourself everytime a dog barks: WE MUST ERADICATE THE MENACE FROM THE EAST!!!

thank you for your time, gentlemen.

shoot for the moon

[xted]

Why are we trying to colonize mars when we have the moon soclose? Think about the possibilities.. If raw materials such as iron where to be refined, the cost to transfer the materials would be cheaper because of the short distance.
Even looking at it from a safety standpoint.. If something were to happen where an evacuation needed to take place, they are that much closer to home. I guess we are just trying to see how far humans can reach into space.

Re:shoot for the moon

[Anonymous Coward]

I heard somewhere (Starcon 2 maybe) that the moon is comprised of worthless elements. The asteroid belt, OTOH, contains huge hunks of really high grade nickle-iron and there's no gravity well to deal with. Ever see that plan for making an EZ asteroid-bubble habitat? Giant mirrors. molten-asteroid-iron-steam-balloon. Spin it. Fill it with dirt&light. Read Larry Niven.

Re:shoot for the moon

[Goonie]

Why are we trying to colonize mars when we have the moon soclose? Think about the possibilities.. If raw materials such as iron where to be refined, the cost to transfer the materials would be cheaper because of the short distance.

Because the Moon, in some ways, is actually not closer to us at all, and there are a lot more things worth having on Mars when we get there.

Firstly, Mars has a day almost identical in length to Earth's. Why is this so important? Because it means you might be able to grow plants there by the natural light. Growing plants under artificial light is very inefficient - the only ones that we can afford to do so for are kind of illegal in many places :) You can't grow plants by natural light on the moon because the two-week night would kill most plants (let alone the problems of your greenhouse heating up to boiling point during the two-week day).

Secondly, Mars has almost certainly got a lot more water available than the Moon does. The moon has virtually no water available. You can't have a colony without a water supply :)

Thirdly, just because Mars is further away doesn't mean it's more difficult to get stuff to and from it. The travel time is an important issue for humans, but for cargo it often doesn't matter, and for cargo it takes *less* fuel to land stuff on Mars because you can use the Martian atmosphere to slow down when you get there, unlike the moon where you have to use more fuel slowing down. Going the other way, it's easier to get stuff off the Moon than Mars (because the moon has less gravity), but you can make rocket fuel for your rocket a lot more easily on Mars than you can on the Moon (because if you have water, you can use electrolysis to get hydrogen and oxygen - instant rocket fuel).

Finally, if you're going to run a self-sustaining colony which pays its own way, to pay for imports from Earth you need something you can export back. From what we know about the composition of the moon, we're fairly sure that there's not much there of value (except for Helium-3, which is a fuel that might be used in fusion power plants in the future but is very difficult to extract), but on Mars there's a distinct possibility of finding high-grade deposits of gold, platinum, and other commercially valuable metals. In addition, if we ever mine the asteroids (many of which are virtually pure precious metal and are thus incredibly valuable), it's much easier to supply the miners with food and supplies from Mars than from the Earth or Moon.

In any case, we're not really trying to colonize either yet. As to the interest in exploring Mars, we've been to the Moon and have a fairly good idea of what it's like. Mars is the next step along the line.

Even looking at it from a safety standpoint.. If something were to happen where an evacuation needed to take place, they are that much closer to home. I guess we are just trying to see how far humans can reach into space.

Re:shoot for the moon

[Anonymous Coward]

Although shooting at the moon would be a logical step.

Fire payloads up using a mass driver (a.k.a. Big Cargo Magnetic Accelerator) and cut down on a good amount of launch costs. Then build the craft in space.

(Of course a orbital platform would be better then the moon...but the title isn't Shoot For The ISS)

Re:shoot for the moon

[Caid Raspa]

if you're going to run a self-sustaining colony which pays its own way, to pay for imports from Earth you need something you can export back.

This is the major hazard of space colonization. You have to get money from it, if you want to pay it with corporate money. And you suggest raw materials!!! I firmly believe transport costs of pure platinum from Mars would be high enough to make extraction from sea water look dirt cheap. Recycling is another thing that will not let the prices go that high. Extraction of gold from used electronics will be cheaper than importing the stuff from Mars.

Information would be cheap to transport, so prodicung it on other planets would be better. For geological/planetological research, every planet will have it's own colony, if robots are not considered better.

However, I think Moon would be the prime place for some sciences: Astronomers would love the continuous two-week data set. Radio interference from Earth would be no problem on the backside of Moon. No atmosphere means all wavelengths (IR to gamma-rays) can be studied from the Moon. Lower gravity means that the telescopes can be made larger. Some deep craters near the Lunar poles are in permanent shadow, so they would be excellent places for far infrared astronomy, where detectors must be at milliKelvin temperatures. To have a 10-K heat sink nearby will make things very easy.

Hazardous biotech research could also be done and safely tested on the Moon. It would be much harder to kill billions of people by stupid accidents.

Another possibility of the Moon is to use coilgun-like launchers that would use solar power to accelerate the cargo. This would eliminate the need for chemical propellant and rockets. Estimated launch price: less than one dollar per kilogram! As launching from Earth will never be able to compete with this, manufacturing satellites etc. could be an interesting option.

Re:shoot for the moon

[cb0y]

Moon is easier

its closer, cheaper
it can have the internet (2sec ping times)
has more materials
no weather, so its safer

damn easy to get to, if they bothered

Re:shoot for the moon

[ascholl]

Finally, if you're going to run a self-sustaining colony which pays its own way, to pay for imports from Earth you need something you can export back.

...like teeth!

Re:shoot for the moon

[drsoran]

Also Mars has that giant alien machine underground that heats up the frozen ice core and releases oxygen into the environment within a matter of minutes to create an instant earth-like atmosphere. Does the moon? No way. So we got that going for us.

Re:shoot for the moon

[gUmbi]

In addition, if we ever mine the asteroids (many of which are virtually pure precious metal and are thus incredibly valuable), it's much easier to supply the miners with food and supplies from Mars than from the Earth or Moon.

If we have access to an asteroid that consists of more metals than we could possible use, don't you think that would eliminate its status as 'precious' or 'valuable'? Gold would be worth less than plastic.

Jason.

Re:shoot for the moon

[mdmhvonpa]

You know, this whole 'Colonize Mars' thing really burns me. Sounds neat, could be feasable except for one little nagging problem. Earth has a molton core which generates a neat little mangnetic band that deflects a bunch of nasty radiation from the sun (this is so non-tech on may part, plz forgive me). Keeps the 'life' as we know it on earth from being irradiated. Well, there are suspicions about the core of mars due to the bizzare local north/south poles all over the surface, and the lack of such a protective band. If life did exist on mars, it was erased long ago when the core cooled.

Re:shoot for the moon

[snarkh]

I firmly believe transport costs of pure platinum from Mars would be high enough to make extraction from sea water look dirt cheap.

Platinum? Even if you were mining hundred dollar bills, the transportation costs would still be too high.

Re:shoot for the moon

[Captn Pepe]

I firmly believe transport costs of pure platinum from Mars would be high enough to make extraction from sea water look dirt cheap. Recycling is another thing that will not let the prices go that high. Extraction of gold from used electronics will be cheaper than importing the stuff from Mars.

Okay, but do you have any particular reason to believe this, or is it just a tenet of your faith? If you consider that fuel can be made relatively cheaply from local ingredients (just react some H_2 with the atmosphere, really) and that transport time isn't important for cargo, it might not be too expensive at all. Strap a booster onto your block-o-platinum and loft into Martian orbit (low gravity, so lots easier than for Earth). Fire up an ion/magsail/Vasimir/whatever engine and two years later you're aerobreaking into Earth orbit.

By far the largest cost to mining on Mars is going to be transporting and supporting the human miners -- which, sadly, makes robots a promising alternative. It'll be interesting to see which gets there first, robots sophisticated enough for autonomous mining operations, or launch costs low enough to realistically support human extraterrestrial colonization.

Re:shoot for the moon

[webcrafter]

But the Moon has this big metallic monolith of aureum proportions, which does... ummm... what is it useful for again?

Re:shoot for the moon

[Anonymous Coward]

Two week light a problem? Obviously you have never been to Alaska before....the sun never sets in the summer. Some of the biggest planes you have ever seen grow there during the summer.

Re:shoot for the moon

[Christopher Thomas]

Okay, but do you have any particular reason to believe this, or is it just a tenet of your faith? If you consider that fuel can be made relatively cheaply from local ingredients (just react some H_2 with the atmosphere, really) and that transport time isn't important for cargo, it might not be too expensive at all. Strap a booster onto your block-o-platinum and loft into Martian orbit (low gravity, so lots easier than for Earth).

You still have to loft the cargo out of the Martian gravity well, and cancel the (very large) gravitational potential energy difference between Mars's orbit and Earth's. This will be about as expensive as launching something into space from Earth - not cheap. Your fuel isn't free. It costs time and effort (read: money) to manufacture, even on Mars.

There's also no reason to believe that mining on Mars will be cheaper than mining on earth even if you *don't* transport the cargo anywhere. Why would we magically find rich veins of platinum on Mars? It has roughly earth-like composition.

If you're going to mine anything, then near-earth asteroids are your best bet, and even then, I'm skeptical of asteroid mining being worth the cost. Asteroid composition varies widely enough that you can find ones that are very rich in metal ore.

IMO, mining the moon for raw mass is probably the most practical operation that will go on in space. To build a space colony, you need a lot of mass just for radiation shielding. Moon dirt works well for that, and is a lot cheaper to loft than material from Earth. If you're building a spinning structure that has mostly tensile forces, then you can get structural material from the moon too (fiberglass cables).

Mars, on the other hand, has little that would be worth transporting back to Earth. In pretty much all cases, you'd be better off mining or manufacturing it on earth and avoiding transport costs.

OTOH, Mars is a great site for colonizing and possibly terraforming, once there are enough settlers willing to pay out of pocket for the trip.

Re:shoot for the moon

[Aexia]

But the Moon has this big metallic monolith of aureum proportions, which does... ummm... what is it useful for again?
It turns monkeys into men and bones into spaceships.

Re:shoot for the moon

[medcalf]

To build a space colony, you need a lot of mass just for radiation shielding. Moon dirt works well for that, and is a lot cheaper to loft than material from Earth.

You state early on that mining Mars or asteroids is unlikely to be profitable, and then state that the moon is better because space colonies need radiation shielding, which can be gotten relatively cheaply by using lunar regolith. Nowhere do you state why people would want to build space colonies, rather than lunar or martian colonies. I'd be curious to know why people would rather build space colonies (which are more difficult to construct and supply) than planetside colonies.

Re:shoot for the moon

[CSG_SurferDude]

Oh....

This must be Alaska exports so much WHEAT/CORN/BARLEY to the lower 48?

;-)

Re:shoot for the moon

[Christopher Thomas]

You state early on that mining Mars or asteroids is unlikely to be profitable, and then state that the moon is better because space colonies need radiation shielding, which can be gotten relatively cheaply by using lunar regolith. Nowhere do you state why people would want to build space colonies, rather than lunar or martian colonies. I'd be curious to know why people would rather build space colonies (which are more difficult to construct and supply) than planetside colonies.

They might not be built at all. I'm postulating that they will be, which leads to my conclusion about profitable space industries. If you assume no large space structures will be built, then I doubt that any space industries will be profitable.

The most immediate use for space stations and space colonies is as way-stations to lunar colonies and for interplanetary craft. This assumes that lunar colonies will be constructed. If we have no need for substantial interplanetary travel or colonization, then there is no need for space stations.

The safest method of building and supplying a moon base or moon colony would be to have two fairly large space stations, orbiting the moon and the earth, with solar-powered ion drive shuttles carrying cargo between them. Build the first station in Earth orbit, and use it as a testbed to work out all of the problems with building space stations and more-or-less self-sufficient environments. Build a second station in Earth orbit, and use ion drives to move it to lunar orbit. Then set up the supply line. Travel time for the ion shuttles is a few months, but they're in a constant stream and unmanned, so this isn't a problem. You now have a conveyer belt carrying food and supplies to the lunar-orbit station, and carrying waste back.

Send construction materials along this pipe, and you can build a lunar colony. Send food and supplies, making sure to keep a month or two of surplus dirt-side on the moon and/or in the lunar station, and your lunar colony can handle just about any disaster without a big, fast, expensive rescue ship being needed.

The earth-orbit station is an ideal launch station for ion-drive probes to other parts of the solar system. The lunar-orbit station is an excellent site to manage construction of other space stations or large craft from (lunar material would be sent to a nearby construction site). This is where you'd likely build a Mars-colonizing ship. The ship would have to be big, carrying all of the equipment needed for a self-sufficient Mars colony base, and would become Mars's orbiting station.

All of this presupposes a desire to build lunar or Martian colonies. Given that desire, this is probably the easiest, cheapest, and safest way of doing it. Without that desire, there's no real reason to go into space at all.

Re:shoot for the moon

[kyrre]

You can't grow plants by natural light on the moon because the two-week night would kill most plants (let alone the problems of your greenhouse heating up to boiling point during the two-week day).

I dont know much about plants but; In the northern parts of my country its Daylight 24hours a day all summer. In the winter its night for about 4 months. And im pretty sure i've seen plants up there. They even have wheatfields in the southern parts. I dont think leting out heat from the greenhouse would be that much of a problem.

Re:shoot for the moon

[La1d]

You can't grow plants by natural light on the
moon because the two-week night would kill most plants (let alone the problems of your greenhouse heating up to boiling point during the two-week day).

The moon has a fixed light side and a fixed dark side. This is due to the rotation and revolution periods being the same. The only time the light side isn't in direct sunlight is during a lunar eclipse, when the Earth's shadow blocks the light from the sum.

Re:shoot for the moon

[slam smith]

Try this. Take a sheet of plywood in the middle of the summer and throw it on your lawn for two weeks. Then pull it off and observe the state of the grass underneath it. You'll have a good idea of the problems facing agriculture on the Moon.

Correct url...

[edgrale]

the correct url is http://dsc.discovery.com/news/briefs/20010827/mars teeth.html

ps. get rid of the horrid 20sec "delay", it's annoying as hell.

Re:Correct url...

[edgrale]

okay, so screw slashdot, after that remove the space between the words mars and teeth and you'll have the correct url...

ps. nice bug :)

Re:Correct url...

[Eloquence]

It's not a bug, it's intentional, to prevent users from posting very long strings that would make your browser show a horizontal scrollbar and mess up the page. If you want to use long URLs, put them in a link instead and they won't be touched (IIRC).

So much for 0g slowing the aging process...

[hillct]

That's right. Go into space, become old and degrepit. Die young, with no teeth.

I'd have to say that NASA will need a more effective marketing campeign.

NASA: So, you want to be an astronaut?

John DOe: I realize I don't have to worry about the space shuttle blowing up, but I don't want to die young, with no teeth either...

Re:So much for 0g slowing the aging process...

[noVox]

However, the first manned mission to Mars televised would be a reality show worth watching. I mean, you could stay sane for 6 1/2 months, but how many people would go nuts? I'd like to see that!

Re:So much for 0g slowing the aging process...

[loraksus]

Rumor is that CBS Executives have been taking to Nasa about Big Brother 68, where those voted off are dumped out of the airlock.

Re:So much for 0g slowing the aging process...

[Anonymous Coward]

The more time you spend around old people the less of a bummer dying young will appear to you.

Re:Thank You Brother

[Anonymous Coward]

We are the only believers. Do You believe my brother? Do You? I do!

Send John Glenn

[Swaffs]

He probably doesn't have any teeth left anyway.

Mars' gravity is 38% that of Earth's

[tcyun]

Once on mars, the effects should be mitigated by the gravitational field - right? How much less is mars' gravity compared to earth?

Mars' gravity, compared to Earth's, is 0.38 to that experienced on earth. Now, I have no idea what this means for bone structure as IANADoctor.

Sign of the times....

[case_igl]

In the old days, explorers ventured into the unknown. If they were very lucky, a third of the original crew returned, crammed into the last ship that wasn't lost in a storm or on an uncharted shallow.

Those who did make it back had suffered - rotting food, no medical care...Peglegs, eye patches, anyone?

Here we are hundreds of years later and our explorers are worrying if they can smile for the cameras when they get back. If they can come up with a way to prevent it, great - but don't set a mission back five years to design around teeth!

I mean...I don't think it's wise to waste men and equipment on a fruitless undertaking, but no new worlds have ever been conquered without a fair amount of casualties. Missing teeth stopping the first landing on another planet (and potentially settling the question of life off our own planet) would be an insult to every great explorer that man has produced.

We need to grow a backbone if we expect to explore, but we won't...Politics and the media make it impossible. Kind of sucks, doesn't it?

Re:Sign of the times....

[number one duck]

As good as this parallel is, there is a substantial inversion going on nowadays. In the old days of exploring, most of the crew were essentially thugs, biomass to keep the ship/sled/canoes going. All the *truly* intellegent people, ignoring the single great explorer on each of these expeditions (grudgingly giving them the benefit of a clue) stayed at home, and didn't have these problems with their fingers rotting off and discovering that fruits really are good for you in moderation. Nowadays we send our absolute best and brightest (or at least the best and brightest we can muster). These folks are precisely the people that wanted to keep their teeth and other extremities in the first place.

Besides, in the olden days of exploration, most people didn't even start with teeth and all their fingers...

Re:Sign of the times....

[windi]

->In the old days, explorers ventured into the unknown. If they were very lucky, a third of the original crew returned, crammed into the last ship that wasn't lost in a storm or on an uncharted shallow.

That's true, we have become lazy assed bastards that sit on our butt all day, but you also have to remember that the explorers of old didn't have to worry about finding air to breath and if they where hungry, they just cast out a fishing line.

But still, we have to take chances, even if, after a failed mission, NASA gets attacked everywhere, even here. And we here should know that working on anything advanced, whether it's an operating system or a spaceship automatically leads you to failures. It's what comes out in the end that counts.
So would you please stop attaching NASA the next time they lose a probe. Every larg projects come up with difficulty sometime or other, but problems are solved, even if it has to be iwth a second probe.

Re:Sign of the times....

[ariux]

Course, in those days, not only were the risks of travel balanced by the rewards of escaping the local law's short arm or coming back with (possibly someone else's) valuable cargo, but your alternative was to stay home, eat boot leather in bad years, and probably die of typhus or cholera.

Our best and brightest aren't going to take up the torch of discovery if it's too much harder than the advanced life of relative ease and comfort they can have right here on Earth.

Re:Sign of the times....

[itarget]

That backbone isn't much help after it atrophies in space. ;)

my teef

[Pilferer]

So all those dreams recently, where my teeth fall out.. are on Mars! I knew something was strange.. wait, am I dreaming that? or is this part of my Rekall vacation?

FUKK THE MARTIANS

[Anonymous Coward]

l00k acr0ss the h0r1zon and s33 a111 th3 myst1ca1 tr011z

b00!

Can't do it that way with chemical propellants

[Goonie]

You simply can't carry enough chemical propellants to do things this way. However, if you developed a fusion rocket this might well be practical.

However, as others have pointed out, simply spinning the ship is by far the easiest and simplest way to get around this issue.

Re:Can't do it that way with chemical propellants

[jTurbo]

Slighltly off topic but here goes:

I recently read about the vasimr engine, a plasma drive running on helium and elctricity. I was thinking what if we tried to combine a fusion plant (it uses plasma and produces helium exhaust) with the vasimr and we should have a efficient impulse drive (just to throw in som st techno babble)

I know fusion plants are not yet mature technology :)

Re:Can't do it that way with chemical propellants

[Anonymous Coward]

Naw. Those propellant rockets are so old school. Build yourself a Woodward drive and not have to bring any propellant.

Artificial Gravity?

[John_Booty]

What if they just created artificial gravity via centripetal force by simply rotating the craft about its axis on the way to Mars? I don't know the physics involved here, maybe it's just not possible to create enough gravity that way unless you have a spacecraft with a really big radius, such as the space station in 2001.

I'm sure that more-informed minds then mine have already considered this simple idea, I'm just wondering why it's not feasible.

If the manned Mars spacecraft wasn't big enough to create sufficient gravity that way, maybe they could just hire really fat astronauts, in order to make the most of the limited gravity. just kidding...

Re:Artificial Gravity?

[Goonie]

It's quite possible. The trouble is that the smaller the "orbit", the faster you have to spin to get decent gravity, and you start getting rather disorienting side effects. However, what you do is get a big heavy piece of stuff (for instance, a spent upper stage of a rocket), a nice big strong (but actually not all that heavy) rope, and attach your Mars vehicle to that, and set the system spinning. If you make your rope reasonably long, the rotation can be nice and slow, and when you get to Mars you just cut the rope and let the useless spent upper stage go.

In Robert Zubrin's book The Case For Mars he proposes just such a system. I haven't checked the physics myself, but it's introductory college physics to do (in fact, I should probably grab my old physics book and do the math just to see if I still can :) )

Re:Artificial Gravity?

[podom]

Artificial gravity would seem to be the way to go. How do you do it? There have been a lot of proposals, of course, and everyone has seen movies like 2001 with big rotating spacecraft and huge spoke-wheeled space stations. One of the most interesting proposals I've seen would use a spacecraft that starts as a single small module for launch, but then seperates into two pieces. Linked together by a long tether, the two halves of the craft rotate about each other during transit in order to create centripetal gravity. I believe that the tether is also used as a power cable, and the power source is in one module with the crew and provisions in the other. In this way, you get a small, light ship with the artificaial gravity benefits that come from have a very long rotational axis. If you're using a nuclear power source, you also get distance-based shielding. --I like flat panel monitors, but fish tastes good.

Re:Artificial Gravity?

[quintessent]

What if they just created artificial gravity via centripetal force by simply rotating the craft about its axis on the way to Mars?

That's exactly what HAL's ship from 2001: A Space Odyssey did on the way to Jupiter. I remember going to the playground as a kid and sitting on a merry-go-round while others pushed. Once it's going fast enough, you'll feel plenty of force. And without friction, it will just keep spinning. Actually, I wonder how much influnce people moving around in there would have. It ought to be easy to compensate for.

Here's another idea for getting gravity on the voyage:

If they could get a large mass to follow them the whole way, then they'd have plenty of gravity. Of course, its size would need to be on the order of the Earth's, but I'll leave the details of implementation to someone else.

Re:Artificial Gravity?

[Anonymous Coward]

Artifical Gravity < 1 RPM is bad.

It's important that any design is comfortable.

Re:Artificial Gravity?

[jareth780]

What if they just created artificial gravity via centripetal force by simply rotating the craft about its axis on the way to Mars? I don't know the physics involved here, maybe it's just not possible to create enough gravity that way unless you have a spacecraft with a really big radius, such as the space station in 2001.

Or a really fast turning radius. But we must consider the dizziness factor. What with the spinning and the stars and the flying colors! The colors, children. The colors! Ayee, blaven!

"That's funny. The damage doesn't look as bad from out here. R2, are you sure this thing is safe?"
-- C-3PO, spinning uncontrollably in the escape pod

Re:Artificial Gravity?

[Evil Pete]

I've always wondered why they dont do this. You probably wouldn't need full Earth gravity and you probably wouldn't even need it for most of the day ... just a guess. So that would reduce the demands on such a system. Just store the angular momentum in a flywheel and when required set a section(?) of the ship spinning enough to mimick say Mars gravity (0.38 g from memory).

Re:Artificial Gravity?

[mabs]

Well, technically, it wouldn't have to be as big, only really as heavy (remember density).

Re:Artificial Gravity?

[proxima]

From my experience, this topic seems to be considered mostly by sci-fi writers. Many people have seen 2001 with the rotating stations. A more recent example is Babylon 5 - the entire station (which is something like 2 miles long and a fraction of that in diameter) rotates. It creates some nice visual effects, but rotation-generated "gravity" has its problems.

The "gravity" is much higher towards the outer parts of a rotating ship and non-existant in the core. In Babylon 5, this is actually where some cross-station transportation took place. They even had the lead character experience the weightlessness of being in the center, with the danger of gradually moving to smack into the quickly rotating station. But that's another story.

Re:Artificial Gravity?

[Rinswind]

In another book of Arthur Clack he proposes an entirely different way to get artificial gravity.
The spacecraft can constantly accelerate with acceleratin equal to 1g. This means that the articicial gravity force will be directed about the spacecrafts axis (immagine a simple rocket here) and the experiance of being inside would be like in a several story building with the lower levels located right above the engine. When the spacecraft needs to stop there would be a short period of 0g during which the whole ship changes direction to 180 degrees.
The obvious drawback is that we don't have enough power (and reactive mass to throw backwards) to constantly accelerate a craft all the way yo Mars and beyond.
A possible solution would be to have a nuclear reactor and use superheated water or a gass of some sort as fuel. In this way we get very high acceleration with relatively little "reactive mass". (in the book they used a small black whole that could accelerate the hydrogen fuel to speeds close to the speed of light :)
All of this being just a theory though. I got no idea if it can realy work.

Re:Artificial Gravity?

[juhaz]

Well, its rather simple - hey dont do it because it would add quite a lot of extra to already hard task of making the space craft, not to mention how much more money they would have to pour it, and the money is something they just dont have these days.

Re:Artificial Gravity?

[Sir Frag-A-Lot]

>It creates some nice visual effects, but
>rotation-generated "gravity" has its problems.

>The "gravity" is much higher towards the outer
>parts of a rotating ship and non-existant in the
>core.

I think it's optimal this way. You could have a fusion-reactor running through the ship, and without gravity, it could actually be easier to contain the plasma. (remind you - the plasma is hold in place by strong magnetic fields to prevent it from touching the reactor walls - much easier if it already floats by itself!)

Re:Artificial Gravity?

[Anonymous Coward]

Err... What are you guys trying to say here anyway ?

You're right, technically it would "only" have to be as heavy. But where to get the mass ? Only object massive enough in the vicinity is... earth. So you propose we just push earth to Mars, and then back afterwards ? Oh, and I'd like to see the rocket that could do that.

Re:Artificial Gravity?

[elvum]

Nah - the pressure in the plasma is a far far greater barrier to containment than gravity.

Re:Artificial Gravity?

[gilgongo]

> All of this being just a theory though. I got no idea if it can realy work.

Well, I have.

Tried it in my Dad's back yard a while ago. Fucking awesome. I used liquid NO2 as fuel though.

Re:Artificial Gravity?

[Christopher Thomas]

In another book of Arthur Clack he proposes an entirely different way to get artificial gravity The spacecraft can constantly accelerate with acceleratin equal to 1g.

A possible solution would be to have a nuclear reactor and use superheated water or a gass of some sort as fuel. In this way we get very high acceleration with relatively little "reactive mass".

If we had enough delta-v to do this, we could get to Mars in less than a week, and the problem wouldn't exist.

It turns out that nuclear power doesn't help us do this.

If we're using a nuclear core to heat fuel directly (as with the NERVA project), we get efficiency comparable to a chemical rocket, because our core (and thus exhaust) temperature can't be greater than the core materials can handle without degrading.

If we're using a nuclear core to generate electricity to power an ion drive or a plasma drive or another class of electromagnetic drive, we have nice delta-v, but very low acceleration, which doesn't help either the bone problem or our total travel time (if we're just going to mars; it would help for destinations farther away).

Other styles of nuclear drive have similar problems. They're great for long-haul trips, but won't give high acceleration and high delta-v at the same time.

Fusion drives won't exist for a while, so they're not a solution candidate yet.

Re:Artificial Gravity?

[Anonymous Coward]

You idiot. Read the article. It suggests this at the bottom.

Re:Artificial Gravity?

[Sabalon]

Well, technically, it wouldn't have to be as big, only really as heavy (remember density).

Well, just get some "I have a book on that" MCSE's and some of the blind /. followers...that should be dense enough :)

Re:Artificial Gravity?

[Anonymous Coward]

"Ah crap...I left my Playboy in the other module. This is going to be a long flight."

Re:Artificial Gravity?

[sean23007]

The Mars Society has already thought of this. You are correct when you assume that you need a ridiculously large vessel to make this feasible. But, the way the Mars Society theorists got around the issue is to separate the craft into two parts separated by a teflon tether, of a sort. The first part of the craft would be larger and contain everything the astronauts would need on the voyage to Mars. The second part would be considerably smaller but nearly equivalent in weight (space for living astronauts is considerable). The two parts would then be spun around each other with initial and occasional blasts from small, dedicated retro rockets.

The problem is, in order to simulate 1G of gravity (equal to that on Earth), you need a certain mixture of size and speed. For safety reasons, the tether can only be so long. So you would think they could just increase the speed. It works on paper, but when put into practice with such a small vessel, spinning at that speed would most likely just induce vertigo in the astronauts and the small size of the craft would allow small variations in the rotation to create noticeable rocking, much like a ship at sea. Luckily, there is an easy solution to this problem. Just simulate the gravity on Mars. Spinning at a reasonable speed, the craft would be able to simulate the necessary 0.38G safely and easily. And then there's less of a problem on both landings (Mars and Earth), because even if you were able to simulate full Earth gravity, would you really want to? When you land on Mars, some considerable amount of time would have to be devoted to getting acclimated to the gravity, during which time the astronauts would not be fully operational and not exactly able to do the required exploration work. With a gravity of 0.38G on the transporting spacecraft, that acclimation can be done over the 6 month travel period and the astronauts can hop out and get their work done immediately after landing.

Re:Artificial Gravity?

[MCZapf]

I've been curious about this kind of gravity since I first saw 2001. Couldn't you be "weightless" anywhere in such a ship, not just in the center? As long as you initially aren't touching any part of it, there's no way it can act on you. It isn't real gravity, so the ship won't pull you down, right? The rotating part will just zoom around you.

Wouldn't it be rather easy, depending on the speed of rotation, to get into a state of weightlessness? Just run against the rotation, until you are moving at the same speed, opposite direction, then push off a little. Presto! Weightlessness! This would only work in a giant wheel, though. Not the tether thing.

Re:Artificial Gravity?

[davonds]

actually that was listed at the end of the article as the most likely cure for the problem. I don't think that a zero g mission to mars has ever been the plan, there are too many physical and psychological problems with prolonged zero g. of course there are other ways to simulate gravity. there is the constant accelleration/deccelleration approach, though this has problems with fuel useage, it greatly decreases the travel time. there is also the new research into artificial gravity/anti gravity production through superconductors.

Re:Artificial Gravity?

[Aexia]

Could something else be used for acceleration? Maybe a rocket booster? Once you get up to a nice speed, let the nuclear drive take over to power the rest of the trip?

Re:Artificial Gravity?

[ReelOddeeo]

If the atmosphere is spinning with the "floor", then you might be floating, but you would have a wind in your face. Gradually, the wind would induce enough motion to cause you to fall back to the floor.

Re:Artificial Gravity?

[Mr. Slippery]

Couldn't you be "weightless" anywhere in such a ship, not just in the center? As long as you initially aren't touching any part of it, there's no way it can act on you. It isn't real gravity, so the ship won't pull you down, right? The rotating part will just zoom around you.

If you were inside the thing, not touching the inner surface, when it started to rotate, yes, it wouldn't affect you.

However, if you're on that surface, you pick up angular momentum. The surface keeps pushing against you, changing your direction so that you move in a circle with it, and that centripedal force is what you feel as "gravity".

If you were standing on that moving surface and junmped staright "up", your center-ward jumping vector added to your tangental momentum vector sum up to aim you right back at the wall, a little bit spinward from where you started. (Too lazy to do the math right now, but IIRC by the time you reached that point on the wall the spin would carry your starting point there to meet you.)

Just run against the rotation, until you are moving at the same speed, opposite direction, then push off a little. Presto!

You'd have to get running pretty darn fast. IIRC a = v^2 / r, so if you had a structure of radius 250 meters (half a klick across - huge) rotating fast enough to give 1g, the tangental velocity would be (scribble, scribble, call up xcalc) 50 m/s, or about 110 mph.

Re:Artificial Gravity?

[Christopher Thomas]

Could something else be used for acceleration? Maybe a rocket booster? Once you get up to a nice speed, let the nuclear drive take over to power the rest of the trip?

The problem is that when the nuclear drive kicks in, you drop to very low acceleration. This brings back the bone degradation problem.

If you're planning to use a mixed scheme for faster travel, the chemical stage doesn't buy you much. You need a certain delta-v for the trip. If the chemical stage gives most of it, it'll be huge (as would an all-chemical solution). If the nuclear stage gives most of it, it'll take a while to build it up (low acceleration). In practice, mixed solutions make sense only where you need short bursts of high acceleration (like takeoff and landing to/from a planet, or fast maneuvering).

For a trip longer than about a year, a nuclear-electric drive will shorten the total travel time. For trips much shorter than that, it doesn't help much.

Still a fascinating topic to think about, though.

Re:Artificial Gravity?

[Aqualung]

If they could get a large mass to follow them the whole way, then they'd have plenty of gravity. Of course, its size would need to be on the order of the Earth's, but I'll leave the details of implementation to someone else.

Ahh yes... there was a McGyver episode about this... some evil drug dealer had trapped McGyver in deep space, and using an old bubblegum wrapper, a used bic lighter and some pocket lint he managed to create an artifical black hole which he dangled in front of him on a stick... when he wanted to go somewhere, he'd just point the stick at it, and he'd "fall" towards the black hole, coincidentally taking him in just the right direction! That McGuyver, he's so smaaaht!
:-P

Re:Artificial Gravity?

[Anonymous Coward]

I think it should read "> 1 RPM is bad".

Re:Artificial Gravity?

[Steve The Avenger]

There might be a couple problems with rotating the craft on its axis for gravity. Think about those carnival rides that stick you to the walls by spinning. Presumably, if a spacecraft used this technique you would be standing where (in the ride) you are lying on your back. Since the "force" pushing you towards the floor is much less, close to the center, your head would be gravity-less while your feet would be super heavy. (The problem would be small in a very large craft, but in a tiny spaceship it might become very hard to move around anywhere.)

Another problem is that it is harder to rotate something that is spinning. (That's why it's easy to balance on a moving bike, but not on a still one). Changing the ship's direction would take a lot more fuel if it was always spinning on its axis.

Re:Artificial Gravity?

[quintessent]

He is amazing. I think if anyone should be working on this long-distance space travel problem, it should be McGyver. It's too bad he's occupied doing Stargate.

ways to combat body atrophy

[tcyun]

As I recall, most astronauts who are in space for any extended period of time have a fairly rigorous workout routine to prevent muscle atrophy. Obviously, exercising with spring based machines (as it is fairly pointless to try to "lift" weights) helps to keep muscles in shape but also stresses the bones also helps maintain bone mass.

The Discovery article states "...in both older women and weightless astronauts, the bone-repair mechanisms in the body shut down." Are there any doctors out there that can explain (in detail) what happens to the body in low gravity that causes bones to atrophy?

Re:ways to combat body atrophy

[Anonymous Coward]

Wasn't the . invented to prevent muscular dystrophy in microgravity environments?

Re:ways to combat body atrophy

[Anonymous Coward]

Cool. Maybe we could get Soloflex to sponsor the mission and save the taxpayers some $$. As an added bonus, all the astronauts would come back after a year built like Arnold. Well, maybe a toothless Arnold.

Regarding your question, bones respond to the demands placed upon them, much like muscle tissue. Repeated stress causes growth and increased strength in both tissues. The article is complete wrong -- the mechanism most certainly does NOT "shut down," it's just not utilized by the typical sedentary 70 year old woman. Same goes for astronauts -- the bones are called upon to support weight, therefore they atrophy. There are countless studies which show that bone density can be increased at any age through moderate exercise and weight training. In, or out of a gravitational field.

The author must have slept through HS Biology class. :)

--
Spaz!

Re:ways to combat body atrophy

[LosBikeD]

IANAD. I don't really know what causes bone-repair mechs to shut down in older women (I personally always thought that osteoperosis in old women was caused by less dense bones than men and losing a lot of their calcium to developing babies). However, I can provide some insight into low gravity issues.

In plain old exercise on earth, there are a wide variety of things that can be done to keep oneself in shape. One thing that is good to do are exercises which keep the bones strong. Things like cycling are great cardiovascular (heart and lungs) exercise, but do nothing for bone health. The issue is that bone healthy exercise is weight bearing exercise. In cycling, the bicycle supports too much of the rider's weight for it to benefit bone health. Things like weight lifting are bone healthy exercises. Just like muscles which atrophy if you don't use them, so will bones. You body has a funny way of adapting to be just as strong as it needs to be. In zero G, you skeleton has very few stresses on it, so it only stays as strong as it needs to.

Re:ways to combat body atrophy

[Anonymous Coward]

No, it was invented to make 46 year-old men in the thrulls of a mid-life crisis spend thousands of dollars on something they will never use.

Re:ways to combat body atrophy

[Anonymous Coward]

(IAAD, and used to be a bioengineer, but this is a gross simplification) Bones continually undergo remodeling, and are as such really dynamic structures. Osteoclast cells resorb bone, while osteoblasts lay down new bone. The clever part of this scheme is that in general, bone microstructure is aligned along stress planes. If you slice through the head of the femur for example, a bone subject to large forces, what you see is essentially scaffolding of bone along and perpendicular to the major lines of stress. This ensures that bone is always strongest along axes subject to the most force, and that bones remain able to bear loads as body geometry changes (with age, injury etc)

This gets you into trouble for example when you replace a joint. A common problem is that bone around the pin of an artificial femoral head seems to melt away. This results from distortion of the normal stresses -- the prosthesis carries most of the load, and the bone is not stimulated to maintain its usual architecture. This also explains why we recommend weight-bearing exercise to our patients.

Wrt the zero-g problem, as you might guess the big issue is that bones in 0-g aren't under load. Osteoclast activity dominates that of osteoblasts, and bone remodeling does not have gravity to orient it. I actually don't buy the argument about teeth in that regard--osteoporosis in zero-g isn't like that of "old age". I'm not convinced that the bone of the jaw melts away in zero-g like that of long bones, but then again it's not really my area.

(docdoc)

Admitted at last

[Anonymous Coward]

AP: August 2001

In a shock move today Linus Torvalds finally admitted that Linux has ceased to be an operating system and bcome a religiion

"for some time now we have realised that to keep up the charade of an operating system was pointless' Said Mr Torvalds. "After all an Operating System is by default something that companies want to use because it is controlled and stable - and we realised linux didn't quite fit"

Mr torvalds then went on to outline how the decision that Linux was a religion came about " we were sitting around one day and we realised that we had all the hallmarks of a religion - we had loyal and vocal supporters willing to believe what they were told by the elders, they would willingly donate their time and money to the good of the cause and were used to irrational behaviour and insane actions and they never miss an opportunity to evangalise the word of the penguin at any occasion"

"plus they already had displayed religious zealotry in the form of Microsoft bashing and abuse of anyone with a different point of view showing the intolerance any major religion needs"

Mr torvalds outlined the basic belief systems of the church and its deities - "the great satan is of course bill gates ! and Microsoft will henceforth be known as "The Great Evil". We have decided to adopt as our symbol and image of Dimitri Skylarov crucified on a cross and the Penguin will of course be our sacred animal"

Mr torvalds went on to declare a jihad on Microsoft, The RIAA, The US Government, FBI, CIA, Every windows user, trolls and Steve Jobs. He also announced a rolling series of tent evagalist shows promising to show people the ture power of the penguin and outlined his plan to follow the hare krishnas and hand out linux distribution cd's to unsuspecting travelers and bus stops and airports.

Bill Gates was unable to be reached for comment due to his being 'doubled over laughing his head off' according to his secretary. Steve Ballmer just jumped around and made stpid noises as usual.

Analysts immedaitely advised customers to sell all of their stock in Linux companies such as VA Linux and Red Hat.

It is not known if this announcement is linked to Dennis Ritchies recent acknowledgment that UNIX was a "college prank that got out of hand"

Re:Admitted at last

[l0wland]

Mr torvalds

Hm, shouldn't that be "Mr Torvalds" ? It's obvious you used the MS Word Spellchecker.

Centrifugal force

[Mad Marlin]

Why can't the crew habitat section rotate around the common axis of the vessel (two modules actually, in order to neutralize the torque generated, spinning opposite of each other). You know, like all of those wheel-shaped space stations you read about in science fiction, just on on a ship instead. Then they could have Earth-normal gravity the whole trip.

Story may be toothless, what about Devon Island?

[dinotrac]

Hope they figure out that tooth problem. Would hate to have our astronauts miss that golden fresh Martian sweet corn.

BTW: Did anybody else get a hoot out of those videos from Devan (spelling?) Island. I think it's wild that grown up, presumably intelligent, people are trying to simulate extended stays on the Martian surface.

Not only do they learn a lot, but they get to wear those neato space suits.

She is so sexy!

[Anonymous Coward]

I like that chick in the story. She is so sexy, even without teeth.

Tooth Faerie

[Amon CMB]

Does the tooth faerie require a space suit?

Re:Tooth Faerie

[DrD8m]

The tooth faerie on space is a Huge Green Bersek Alien. Better they don't loose any tooth!

How much spin?

[Robber Baron]

Even better would be to avoid the problem altogether by building a spacecraft that spins, generating artificial gravity, said Marsh Cuttino...

Uhhh, just how much spin would be needed to generate enough simulated gravity to cancel the onset of osteoporosis, and can you imagine the havoc that would play on the spacecraft's structure over time? Hell of an engineering problem to wrestle with...

On the other hand can you imagine a year of zero G sex?

Re:How much spin?

[Anonymous Coward]

>On the other hand can you imagine a year of
>zero G sex?

You mean... zero G toothless sex.

Mars Fact Sheet

[dragons_flight]

Here is the Mars Fact Sheet from NASA. The surface gravity on Mars is 0.377 times that of Earth, which I would expect to cause at least some bone loss, but of course IANAD.

Incidently the year in space, 6 months each way, seems somewhat short to me. I thought they generally planned for closer to a 9 month journey when sending things over there. Of course the really important point is whether we can make more fuel once we get there. Carrying all the fuel for a return trip with you would make for a lot heavier and slower trip.

In any case men won't be going there soon. We haven't even been to the moon in ages, and we might as well test whatever technology we plan on using on some long duration lunar missions.

No more cavaties

[bee-yotch]

What are teeth good for anyway? I'm sure they can just get nasa to hook them up with all liquid food, I hear it's pretty tasty. ;)

So much for THAT stereotype!

[CaptainCarrot]

So much for the standard picture of the intrepid space explorer! I doubt Doc Smith would have sold so many books if his main character in the Lensman series was named Kimball "Gums" Kinnison.

Simulated Gravity En Route, Gravity On Mars

[JohnPerkins]

Cost aside (ha!), if they were to build something like the Leonov in "2001", making the arms longer would increase the apparent gravity at the ends. Balance the relationship between arm length and angular velocity to get 1g at the ends. Do that many of the degeneration/atrophy issues ought to disappear.

On Earth, it's 1 g, on Earth's moon it's about 1/6 g, on Mars it's about 1/3 g.

Maybe I ought to take a crack an idea I had a few years ago for a cheap launch vehicle- sort of a motorized bolas...

Mmmy gawwd, iss fuwl au staawsss.

[Anonymous Coward]

(How I'd imagine it pronounced; sans teeth)...

Are you volunteering?

[Jagin]

Heh.. I mean.. its in the name of adventure and exploration, right? I'm sure NASA would love to hear from guys like yourself.

Other problems to be concerned about...

[hound3000]

Tooth loss is one thing I never really thought about for a manned mission to Mars, but it is just one thing. What are the other problems we have to solve to send humans to another planet? Besides the obvious DVD region jokes, and money from Washington DC?

• You have to send enough people so that they all don't go crazy. We will have to a system like HAL in the long run?
• Creating Artificial Gravity, most likely only way to go...
• Are there any ideas to shorten trip time?
• Are we going to send a unmanned mission to set up a nice cushy environment for the astronauts to stay at once we're there? A small bio-dome? How will that work?
• What exactly are we going for anyways? Search for water, search for life like bacteria? Origins of the universe or solar system?
• How long will it take for permanent Moon/Mars colonies, 100+ years? Why will we need those?

Is there any better comprehensive list out there listing all the dangers with possible solutions on space travel out there?

Nice headline

[Faust7]

I'll just say kudos to Hemos for the attention-grabbing headline. Made me giggle even before I read the story. :)

IE 6.0 is ready for the downloading

[Anonymous Coward]

I found a brief article on ZDnet that announces the release of IE 6.0 for download. The article is here

ahh life is good...

[Anonymous Coward]

jerking off while browsing at -1... mmm mmm mmm...

Re: Fuel can be generated

[jeti]

As Robert Zubrin describes in his book "The Case for Mars", rocket fuel can be generated with a simple, proven reaction from the martian atmosphere.

And no - the book is NOT a fictional work. Robert Zubrin is the guy convinced the NASA to change the plans for manned mars mission to the "long trip model".

Lost teeth?

[Trollificus]

"Expert: Mars Astronauts Would Lose Teeth"

Not if they leave them in the cup next to their bed at night. ;)

It's possible indeed

[jeti]

It is possible to use last, burnt out stage of the rocket as a counterweight. You tether the stage and the landing module together and give the components a spin.

Calculations suggest that this is indeed possible. I think the idea is explained in more detail in
"The Case for Mars", a highly recommended, factional book.

IE 6.0 has been released

[Anonymous Coward]

Read about the release of the new Internet Explorer 6.0 here on news.com

Feed them lots of taffy! 1 meal = no more problem

[stevarooski]

Bone weakening? Lost teeth? Sounds like the normal effect of a 'geek' diet to me. Bring it on!

-s

teef?

[FFON]

i already got no teef... can i be a astronot?

A perfect solution:

[quintessent]

If they switch the minty-fresh taste of colgate, their teeth will stay strong, white, and clean.

Return trip?

[mortonda]

That way you can just pop a bolt when you get to Mars,

Um, what about the return trip? Do we not want gravity for that too? Or have we not planned for the return trip?

Re:Return trip?

[Goonie]

Once you're in orbit, the rocket engine that lifts you off Mars is expendable. Hence, you get another rope and hook it up for the return trip.

I should point out that in Zubrin's Mars Direct architecture the habitat that you do the trip there on, and the vehicle you use for Earth return, are two different vehicles, but even if they were one and the same it doesn't pose a major problem.

Permanent tooth loss

[WhatWasThat]

"The bone-weakening effects of zero-gravity environments might lead to permanent tooth loss, says a government dentist. "

Can it be non permanent ??!!

Re:Permanent tooth loss

[Anonymous Coward]

Not with Crest's new stem cell tooth enjection...a few shots and a in no time you'll be searching for a teething ring.

Re:Permanent tooth loss

[Anonymous Coward]

Just send young atronaughts - before they get their adult teeth.

What about the Russians ?

[windi]

There are russians that have been in space for 6 month to a year and they have not lost their teath, and I have not heard of any problems with anyone spending time on Mir, and no one has said anything on this topic before (AFAIK, I can't read the article :-( ), so assume that the ISS astronauts are in no danger, and they are supposed to spend six month in orbit.

So, IMHO, the article was written by someone who is against a manned mission to mars or any other planet.

Re:What about the Russians ?

[Anonymous Coward]

So six months in space doesn't make your teeth drop out. Neither does staying underwater for 30 seconds make you die of asphyxia.

Now try six minutes underwater

Other Options

[Sensei_knight]

What if we raised a few humans in space in simulated Mars gravity? Bone Loss wouldn't be a problem because the body would be optimised for Martian gravity. I also beleve these humans would be considerably taller. Much foresight woould have to be used in the construction of their craft.

No break down of calcium structures because their bones would be built from the ground up to meet their needs at that gravity. As opposed to to earth astronauts who experence a break down until excess is depleted to balance with necessity and environment.

Maby this could be an application for gene therapy.

Only sad thing would be that they could never come "home". They would most certinally die in earth gravity. =(

Re:Other Options

[Anonymous Coward]

Err, human beings most certainly don't adapt to arbitrary circumstances when they grow.

More likely a human born in space would grow to be physically handicapped and survive poorly under any circumstances. Or at best, would grow to be physically normal but extremely weak.

Re:Gravity == Acceleration? - not really

[Technomancer]

Mars Distance from Earth
Minimum (10^6 km) 54.5
Maximum (10^6 km) 401.3
at 10m/s^2 acceleration/decelaration
whole journey would take 42 hours minimum
112 hours maximum
top speed would be 734km/s at minimum distance
or 2000km/s at maximum distance

Fake Teeth?

[Anonymous Coward]

I guess this might turn off a few candidates for
a mars mission, but why not just give them fake teeth before they leave? Sure, it most likely
is not the most enjoyable thing in the world, but honestly, I would take a set of fake teeth screwed right into my jaw if it meant I could go to Mars. I just think it would be silly to let something like this slow us down in space exploration at all.

Of course the even better idea is to make spacecraft in space, so we can just have a large circular object that spins, creating it's own gravity.

Why not spinning space ships?

[gisborne]

Why aren't we making spinning space stations like on 2001? Surely this would solve this whole problem.

Re:Why not spinning space ships?

[DarrylM]

Hopefully, if NASA can get the funding, a rotating lab will be present on the ISS so they can do experiments to determine how well spinning the module actually works as artifical gravity.

That would be cool!

Now we know what happened to

[CptnKirk]

ET and all the Roswell aliens. Years of space travel has caused teeth and hair loss, and either body mass compacting (under it's own weight and lessened bone strength), or body elongation due to uncontrolled juvenile growth spurts in microgravity.

Moderate parent up to the roof

[Anonymous Coward]

These "experts" on bone-weakening effects of zero-G environments need to know that their research is as useless to space travel as whip design research is to car travel. That's just not the way things will go.

30 Hertz vibrations

[Ratface]

Just this morning I was reading issue 2303 of New Scientist and read an article that states that research has shown that the activity of standing on a vibrating platform moving at 30 hertz for 20 minutes a day has induced sheep to gain 35 % more bone mass within a year.

Trials have been started on elderly female patients with osteporosis and seem to be showing positive results.

Of course, 0G could make it difficult to stand *on* a vibrating platform, but these experiments must be able to teach reserachers something about ways to combat the problems. If tiny, high frequency strains can help improve bone growth then there must be other ways to induce those strains within a 0G environment.

Re:30 Hertz vibrations

[MOMOCROME]

floating in fluid moving at 30hz would have a similar effect.

Re:30 Hertz vibrations

[Evil Pete]

This is probably related to the fact that bone is piezo-electric. Which means that it has to be asymmetrical stress on the bone to induce the result. So being in fluid wont work .. You'd probably need a good contact with the mat .. or a weak artificial gravity.

Re:30 Hertz vibrations

[Pseudonym]

I used to know a physiotherapy postgrad student who was researching the use of ultrasound to achieve a similar effect. Ultrasound is more like 3500Hz, of course. Still, you can use it in zero gravity.

Re:30 Hertz vibrations

[ghard]

I remember reading an article that hypothesized that this might be the reason behind felines' ability of healing. The purring seems to promote bone mass growth by a large percentage. A quick google search brought up this article on the subject.

arrangements Saddam Hussein bomb Peking Honduras radar North Korea
Qaddafi KGB SDI NSA jihad Clinton counter-intelligence munitions

Re:30 Hertz vibrations

[Thomsen]

More information on vibration maschines for use in gaining muscle and bone strength can be found here.

This link shows how the vibration maschine works.

With respect to the story on Discovery: There is a factual error in it. Females do not have lover bone density than males. The volumetric density of male and female vertebrae are identical. However, females have generally smaller bones than males and the force needed to break female bones is therefore smaller than for males. On the other hand the stress (force divided by cross sectional area) needed to break female or male bones are identical. More information can be found here.

Re:30 Hertz vibrations

[hlee]

What about tuning a Braun Plaque Remover? Brushing for 20 minutes a day - no flippin' dentists in space that's what!

Re:30 Hertz vibrations

[Anonymous Coward]

Reference to H2G2: +1 Funny
Copy and pasting the linked article: +5 Informative
A troll tells you to grow up: Priceless

Re:30 Hertz vibrations

[sinator]

Okay, but here's the question
Using your muscles helps improve bone density. This is why weight lifting helps to strengthen your bones.

Is the vibration *per se* causing the bones to grow, or is it the thousands of miniscule muscular movments a sheep would have to make to remain steady on a vibrating platform that is causing the bones to grow?

I'm not being argumentative, I'm just curious, because if it *is* the muscle movements that help strenghten the bone, you wouldn't need a vibrating platform, you'd just need a few electrodes implanted in key places and twitch all night ;)

Re:30 Hertz vibrations

[Anonymous Coward]

I think the sheep with their four legs would stand quite stably on the platform without moving at all, assuming that the amplitude is reasonably low (if it was something like 10 cm you'd just break their bones. So it'd have to be about a millimeter or less).

So I _guess_ that it's an effect resulting from the vibration of individual bone cells, not muscles or other stuff. If it was just something picked up by another body part and the growth command was sent to the bones with hormones then we could just use those specific hormones and skip the low frequency sound treatment.

-- pinkNoise (who has forgotten his /. pass)

Re:30 Hertz vibrations

[Anonymous Coward]

Useless trivia snippet #43229:
The purring sound which cats make is thought to stimulate bone growth in the animal, which might otherwise have quite brittle bones considering that it sleeps for 18 hours per day.
--
Spaz!

Re:30 Hertz vibrations

[Myco]

floating in fluid moving at 30hz would have a similar effect.

I very much doubt that. A fluid will not oscillate in a rigid way that will transmit those vibrations uniformly into a solid body.

Why not just sleep in a 1g centrifuge?

[tonywong]

I doubt that you'd need a 24h/day 1g environment to prevent bone density loss, so why not just sleep in a small centrifuge compartment that puts them in a 1 - 1.2 g for 6 - 8 hours a day? The energy output would be minimal and the astronauts could take shifts in the centrifuge.

Acceleration or Spinning, both are hard.

[dragons_flight]

To give you some idea of how far we are from this. If you could afford the fuel to do 0.5 G to half way and then flip to slow down, the whole trip takes only 2.4 days at Martian closest approach. Ramp it up to 1 G and you get things down to 1.7 days.

Simulated gravity could be made this way but no engine design has fuel sufficiently light to make this even remotely possible with current technology.

As far as spinning. Acceleration = Radius * (angular frequency)^2. To get a good one G in a ship with a 5 meter radius, you'd have to spin it at 1.4 revolutions per second. Okay so make the ship bigger and aim for less gravity? 20 meters for 0.5 G still carries a rate of 0.49 rev. per sec. Spinning isn't generally a simple answer unless you are planning something that is monumentally huge. A station 2 km across can get to 0.5 G with one revolution about every 14 seconds. (If you feel like making the stretch to call that simple.)

Someone might point out that without air resistance or other interactions, getting and keeping a spin isn't the problem it would normally be. This is true, but if the object is small you get all kinds of wierd effects caused by the gradients in force. For instance a 1m tall person standing in that 5 m ship at 1G would have only 80% of the gravity at his feet acting on his head.

I will concede that getting such a ship spinning takes not unreasonable amounts of energy (considerably less than would presumably be spent getting it to Mars at a reasonable speed, and not a problem if you start the spin while in Earth orbit and fuel is plentiful), but then you pretty much have to go in a straight line along the axis, because you've just made the largest gyroscope man's ever seen, and turning the thing would be a bitch.

Some of the other problems would include getting in and out of such a ship (think floating through a hatch on the axis and then somehow matching rotation). Also anything on the outer wall would want horribly much to fly off. Large stresses would be involved in getting it spinning and holding it there. And last but not least on my short list, is that any propulsion system would carry both mass and angular momentum away from the ship affecting the rate of rotation.

Okay, so I've sat down and done the calculations. Sustained acceleration isn't likely to work any time soon. Rotation is technically possible, but certainly not easy given the kind of speed needed and presents serious technical issues to deal with the stresses, manuevering, getting in and out of the ship, etc.

Good luck NASA, I hope you figure something out in my lifetime.

Re:Acceleration or Spinning, both are hard.

[Anonymous Coward]

As far as spinning. Acceleration = Radius * (angular frequency)^2. To get a good one G in a ship with a 5 meter radius, you'd have to spin it at 1.4 revolutions per second.

Hum, the formula is: accel = radius * (2*Pi*rps)^2, so to get one G in a ship with a 5 meter radius you need 0.223 revolution per second.

Rotation is technically possible, but certainly not easy given the kind of speed needed

Speed for the 5m wheel: 5 * 2*Pi * 0.223 = 7 m/s = 25 km/h. You call that hard?

Re:Acceleration or Spinning, both are hard.

[Anonymous Coward]

I've never understood why this isn't given a higher priority for Mars mission planning (maybe it is, but not by the journalists I see on TV).

Sure, spinning is hard, but the manifold problems resulting from zero G make a Mars mission much harder. I watched a documentary recently concerning plans for a Mars mission, and nearly the entire length of the program was devoted to the problems of zero gravity. Despite this, approaches to simulate gravity were not mentioned once.

Mind you, the radiation sounded a bit nasty too!

Re:Acceleration or Spinning, both are hard.

[Anonymous Coward]

I watched a documentary recently concerning plans for a Mars mission, and nearly the entire length of the program was devoted to the problems of zero gravity. Despite this, approaches to simulate gravity were not mentioned once.

NASA biologists are all excited to study the effects of zero-G on the human body. Don't ruin their game with a simple Physics101 solution, they might not like it.

Re:Acceleration or Spinning, both are hard.

[esonik]

For instance a 1m tall person standing in that 5 m ship at 1G would have only 80% of the gravity at his feet acting on his head.

I think it's safe to assume that the average persion will be 1.8m tall *g*, i.e. experience only 64% of the feet-gravity at his head. Also things that fall "down" towards the outer cylinder wall would not do so in straight line in the rotating observer frame of reference but in a curved line, due to the Coriolis effect (of course in the non-rotating frame of reference it's a straight line). It would be a weird experience to pour yourself a cup of tea *g*

start packing now

[nashira]

1: "We don't want a lot of toothless astronauts returning to Earth," said periodontist William Stenberg, a commander in the U.S. Public Health Service.

2: It's long been known that astronauts and cosmonauts who spend weeks and months in the microgravity of orbit rapidly lose bone density and mass.

All that sounds like a conspiracy. I think what they're really saying is we should pack granma's stuff. I repeat: we should pack granma.

artificial gravity

[bhny]

NASA is considering puting a centrifuge on a mars mission.
The 1998 Neurolab mission on the space shuttle had a centrifuge that produced 1G. this was basically a spinning chair.

from the paper " Perception of tilt (somatogravic illusion) in response to sustained linear acceleration during space flight "

these results suggest that astronauts exhibit appropriate
perceptual and oculomotor responses to artificial gravity
during short-duration missions. If these responses are
maintained during exposure to artificial gravity on long-duration
space flights, interplanetary missions can proceed
with the expectation that the astronauts will respond
normally to the gravitational fields of other planets
when they are encountered.

not sure if this will help their teeth, but it does seem to indicate that spinning the astronauts can overcome some of the problems of weightlessness

Yes,Gravity = Acceleration

[maxwells_deamon]

This is the precise basis of the General Theory of Relativity.

An man in an elevator (space capsule) can not tell them apart.

you are accelerating in either case. On earth it is just due the the bending of space and time.

The math involved is left as an exercise for the student. ;-)

Re:Gravity == Acceleration? - not really

[Anonymous Coward]

Excellent post. I don't think some people realize what effect 9.8m/s^2 acceleration means in terms of how much it will affect your speed on a trip of that large a distance.

Who said zero G ?

[grungie]

There's no such thing as zero gravity.
And Mars has a G higher than 1/3 that of Earth (3.4 or something like that, I don't know by heart) which is not what can be called microgravity.

So there should be no major problem at that level, when on martian ground at least.

Re:Who said zero G ?

[pne]

So there should be no major problem at that level, when on martian ground at least.

You've got your answer right there -- what people are worried about is not so much the effects of living on Mars but of the trip there and back, which will occur in microgravity since 1G all the way there would cost way too much fuel.

It's not a BUG ... it's a FEATURE

[Skapare]

That's right, it's a feature. The space is inserted in the displayed text, but not in the href= attribute of the HTML <a> tag. The space is inserted to prevent long "words" that can't be wrapped by all browsers from messing up the site format.

OOPS

[dragons_flight]

Lost track of the units, it's radians per second in the rotation numbers, not revolutions. That means the correct values are:

0.22 rev per sec at 5m, 1G
0.078 rev per sec at 20m, 0.5G
One rotation every 85 seconds at 2 km, 0.5G

Makes the thing look even better than I thought but still not slow.

Re:OOPS

[Konovalev]

True, if you're thinking of making a great big can. That would be massive, heavy, expensive, etc. But you could just make a ship consisting of two modules - one habitation and one service, say - and tether them opposite each other to a common hub which would also contain the engines. That way you could spin them fast without having to build a great big can. Basically the ship would look like a bean can with two tetherballs attached to opposite sides.

Oh, just one more thing... in fact, you'd have to make two pairs of modules and spin them in opposite directions. Otherwise you get precession, which makes steering a bit tricky. When you arrive in Mars orbit, stop the spin, winch in the tethers, and send down the landers.

Important: make sure the tether doesn't break. Otherwise your precious astronauts go whizzing off on an eccentric orbit somewhere between Earth and Mars, out of the ecliptic plane (probably) and die. But building a 2km tether to support a 20-tonne module shouldn't be impossible. Anyone?
Also, make sure the two sides don't get out of balance. Ballast weights that can be winched up and down the tether - or just winching in or out a bit to balance the angular momenta - are best for this.

It's not as if it's an insurmountable problem.

[Shadox Tsurien]

Why don't we just try to fix the problem, instead? It's probably not that difficult of an issue. Soon, someone will probably come up with a vitamin supplement or some sort of artificial gravity (maybe by spinning the ship) that will fix the whole issue. So why push it?

Besides, we're worried about psychological issues between the crew of these spacecraft. I'm sure that serious and extremely nasty dental issues won't help that.

So instead of growing a backbone, I say we just wait a couple years and grow a brain instead. That way, we'll have fairly happy astronauts returning home instead of toothless, frail, half-insane wrecks.

Tommyknockers

[Mxyzptlk]

I know what this is all about, and Stephen King also knew it a long time ago: it's the Tommyknockers! Think about it: the teeth start falling out, aliens are involved, and all of a sudden there are lots of people that can do these extremely advanced technological stuff. The next thing that will happen is that the astronauts start stealing a lot of dogs and hook them up to ISS, instead of using solar panels... Don't say I didn't warn you!

30 Hertz : Not Tiny, Not High Frequency

[VividU]

That you would be 30Khz which is a tiny high frequency indeed, beyond the perceptible hearing range of most humans.

30Hz is deep and low. Audible too! ( if you got good ears ).

Re:30 Hertz : Not Tiny, Not High Frequency

[Ratface]

Well, I don't remember much about frequency from my physics lessons at school, but I thought I should just confirm that the article states 30 hertz. They also describe the movement as imperceptible:

"The researchers have found that when sheep are made to stand on a platform vibrating at an imperceptible 30 hertz for 20 minutes a day, their legs gained 35 per cent more bone mass within a year", oh, it also mentions that the information comes from Nature vol 412, p 603.

I must admit that the story mostly stood out in my mind because I had a great image of sheep being made to stand on a vibrating platform that made them wobble around and lose their balance - but then I was on the tram to work so my mind was wandering!

Re:30 Hertz : Not Tiny, Not High Frequency

[Ratface]

... and in my last post I forgot to agree that yes, of course you're right. 30 hertz is neither tiny nor high frequency!

Re:30 Hertz : Not Tiny, Not High Frequency

[WebMasterJoe]

but then I was on the tram to work so my mind was wandering!

I bet the tram was vibrating at more than 30Hz!

Re:30 Hertz : Not Tiny, Not High Frequency

[Sir_Real]

So will this work for me? Could I make a vibrating platform and become more caveman like?

The possibilities are ... well ... kind of dumb ... but I still want to try it!

Re:30 Hertz : Not Tiny, Not High Frequency

[blair1q]

What exact amplitude do they call "imperceptible"?

A few mm? A few um? A few nm?

--Blair
"Gotta love those irreproducible results."

don't float blind!

[GroovBird]

Astronauts should worry more about their personal safety then the missions they are assigned to. I'm sure most of them occasionaly get so tired they just 'close their eyes for a second' and then smack into control panel. They seem to forget that the law of physics dictates that an object that is in motion wants to stay in motion until it smashes its face into another object.

No wonder they keep losing teeth.

ther way...

[manon]

We all know there are ways to generate gravity.
This can be done by clinorotation. Here is more about that.

I'll volunteer!

[Anonymous Coward]

I'm already missing half my teeth and I don't even care if they get me back safely. How many get to say they died on Mars?!

What some people would give...

[Anonymous Coward]

Some people would give at least their eye teeth for such an opportunity.

Maybe not all 30, though.

Hold On!

[redcliffe]

A Russian astronaut who holds the world record for time spent in space, stayed in space for more than a year in one go, and didn't suffer any long term side effects. I can't remember the details, but it did happen.

David

If I ever meet you...

[Anonymous Coward]

If I ever meet you I will smash all your teeth out!

The Speed of the Spin Required

[rosssw]

The formula for the acceleration due to cetripedal (centrifugal, it's not the same, but you get the right answer) force is a = v^2/r, where a = acceleration, v = velocity and r = radius of rotation. If we assume a = 10 (m/s/s, not feet), then we get 10 = v^2/r.

Lets make r a value such as 100m. To get acceleration due to gravity on earth as centripedal force, you would require a velocity of about 31m/s(131km/h, 81 mph) going around in a circle.

That's quite fast to be travelling in two dimensions (going forward and laterally), I don't think it's possible without getting too dizzy.

Re:The Speed of the Spin Required

[kghougaard]

You would not get dizzy. You cannot "feel" velocity, you can only feel accelration.

In a rotating spaceship you would constantly be accelrated towards the middle of the circle --- by the centripetal force (The floor would push you).

You would feel an imaginary force downwards --- the centrfugal force --- originating from you trying to continue in a straight line.

This would feel exactly like gravity --- which of course was also the purpose of it all.

You would only be dizzy (I think) if the circle was too small. Then there would be a large difference in artificial gravity for your head and feet. Things would no longer fall in a stright line (downwards :-) if you dropped them. Imagine r=2 meters. Your head would stand allmost still, while your feet spinned violently around :-) That would make you quite dizzy I think :-)

Kristian

Ultrasound

[Anonymous Coward]

Actually isn't ultrasound by definition above the range of normal human hearing (i.e. 20Khz)?

Perhaps you mean 35000Hz?

Re:Ultrasound

[Pseudonym]

Sorry, I left out a "k". I meant to say 3500kHz, not 3500Hz. And I know that figure is right because I read it off the screen when my wife had a scan last night. :-)

These machines have come a long way since when I briefly did some work with them 11 or so years ago. (I never got to operate the machines, of course. I just developed film. This was in the days before ultrasound and CT scan machines had photo printers hooked up to them. I digress.)

You can work it out from the knowledge that the average speed of sound in soft tissue is 1540m/s. A 3500kHz frequency gives you a wavelength of 1540/3.5e6 metres or 0.4mm, which is the sort of resolution that you need for diagnostic purposes. Diagnostic imaging devices can use different frequencies, of course. Typical range is 1-15 MHz.

It's all down to politics

[desdemona]

NASA's new Mars reference mission is mostly based on Zubrin's The Case For Mars, but crucially, the rotating-with-tether idea for minimizing bone-loss idea has been dropped.

NASA has invested decades of research and gazillions of dollars into investigating medical responses to weightlessness - indeed, it's often cited as the reason for manned space flight. They can't back down and say that Oh, actually, a tether-based system is quick and easy... They cite difficulties in communication (e.g the antenna is rotating) as the main reason why the tether system won't work, but personally, I don't think that's an insurmountable problem. The benefits of doing a 9-month trip in decent (0.39g) gravity far outweight the hazards of having an antenna which will need realigning with that pesky precession.

evolution

[belbo]

If I remember my biology classes correctly, teeth already are regarded as an evolutionary relic by some biologists, so they are bound to disappear anyway some time 'soon' (on the evolutionary timescale, that is).

What's more: *of course* humanity will adopt to living in space, they will look different from the people living on earth, that's the whole point in evolution, isn't it?
That this might bear some problems for the first spacefarers has already been a topic in SF literature, e.g. in C.M. Kornbluth's story "The Altar at Midnight".

tom

Re:evolution

[Anonymous Coward]

And how exactly does natural selection work in this case?

In fact, how does natural selection work at all these days? Practically everyone spreads around their genes apart from a few exceptions.

Then again, apparently you are a believer in a mechanism of evolution that we are unaware of.

Re:evolution

[Asic Eng]

Well, from archeaology lectures I remember the claim that humans are essentially genetically unchanged for the last 40000 years, so any adaptation of this kind would take a very long time.

Also we have to keep in mind that evolution does not necessarily work to improve the species(1), it's not a planned process in any way. For it to advance the appearance of certain features, people who have those features need to have more descendants than those who do not.

I don't think this is happening at all, at least not in western societies. Since pretty much everybody has access to sufficient food and shelter the likelihood of propagating one's genes seems to be almost entirely tied to inclination and maybe (somewhat) to attractiveness.

Today it's so much easier for us to change our environment than to adapt to it, I don't think evolution will have much of a role to play anymore.

(1) Think of the many species with ridiculous and impractical horns or tail feathers etc.

Re:evolution

[Anonymous Coward]

It seems like half the time they can't even launch a large satellite in earth orbit without having problems like the solar panels getting stuck. Getting the kind of spin required for 1 G without crewing up the gyro or mechanical failure is impossible. Also, how would we launch something that big?

Re:evolution

[xXgeneric nicknameXx]

If I remember my biology classes correctly, teeth already are regarded as an evolutionary relic by some biologists

I would say that either 1) you don't remember correctly or 2) "some biologists" don't know what the hell they're talking about. Teeth are essential for proper nourishment as they grind food up to a point where saliva can start the digestion process.

Can you imagine trying to chew a steak with your gums?

And so?

[Ektanoor]

And while we keep waiting to see some toothless astronauts, the brainless bureaucrates keep us tight to earth...

health service periodontist

[davemeg]

It is my understanding that zero gravity loss of bone density ocurrs mainly in weight bearing ereas such as the spine and hips. The jaws would be un affected.
Having practiced oral surgery for 13 years I've found that periodontists in particular tend to use scare tactics to get people to schedule periodontal surgery.

John Glenn

[Anonymous Coward]

I guess that John Glenn would be ready for Mars then.

First Reaction:

[Satai]

"Tommyknockers, Tommyknockers, knockin' at my door..."

Gum anyone?

[M_T_Toaster]

Wouldn't chewing gum give some protection against this?
It would give them plenty of exercise to the teeth and jaw muscles, and might well be popular (most astronauts are American now and so presumably like chewing the cud).

OTOH the gum might also come in handy for fixing things in the ship and or holding things down in zero g

think of the sponsorship deals... the Wrigley's Orbiter etc

no gravity = no teeth ...

[xtermz]

so.....does this mean there is less gravity in all the worlds trailer parks.....???

And what of MIR?

[OldCrasher]

I suppose the cosmonauts that rode MIR for more than a year were some how in a different form of Zero-G. I suppose that Russian Space being different to US Space, their research is useless... And assuming this means that some Dunderhead can still get Federal Tax Dollars to do research that someone else has already done.... better.

big deal

[Anonymous Coward]

so they lose a few teeth.. can always grow them some more out of stem cells.

No water on the moon?

[Penguinoflight]

I think you got it backwards, we have no evidence that there is water on mars, but there has been ice discovered on the moon already. Get your facts straight before you go on a long rant.

Re:No water on the moon?

[Winged Cat]

No...there is definitely water ice on Mars (check the polar ice caps). There may be ice on the Moon; the last probe to check came up about as inconclusive as whether there was life in that Martian meteorite.

But there is oxygen on the Moon, and hydrogen from the solar wind if nothing else. Add in electricity (solar panels - at the poles, where they could always be in sun - anyone?), and...

Re:Backwoods of Arkansas...

[twitter]

I hope you could out run old Bill Clinton! I'm told that was the only way to keep him off your back. Oh sorry, that's an Asstronaut.

Go Go Kentucky Space Program!

[tenzig_112]

Who needs teeth when astronaught food is generally pasty anyway?

I know some tooth-impaired good ol' boys who would be excellent candidates for the Mars program. Far from pretty boys, they would not mind at all losing their remaining teeth.

NASA should also contact Shane McGowan [formerly of The Pogues] if anyone can find him.

In thpace ... no one can hear you thcream.

Ironic isn't it?

[ZeroKicks]

Does anyone else find it ironic that this is a sort of "space scurvey"? My my my... the parallels of the voyages of exploration of old and the voyages of today.

Market Oportunities

[Marvin_Runyon]

Just think of the market potential for apple sauce and oral sex!

nah - use unwashed california eco wannabees

[Anonymous Coward]

they are much better and accustomed to
unwashed-ness

toothless women astronauts?

[bobalu]

gee, takes some of the romance out of zero-G sex, doesn't it? Hmmm.... or maybe not!

But do we need gravity everywhere?

[Raptor CK]

I know that we all think that a spinning spacecraft is a wonderful idea, but it's a bit much.

What about just a single chamber, perhaps along the lines of living quarters, that spun, much like the old amusement park rides?

A certain amount of exposure to ~1g per day should be enough to ward off the deterioration of bone mass, and it would be cheaper than engineering an entire spaceship to spin fast enough to induce gravity.

Of course, I'm certainly missing the key detail of this spinning chamber most likely staying in place while the rest of the ship spins, but I leave the tough work to the NASA engineers :-P

So what?

[peccary]

I would give my eye teeth for a trip to Mars, and so would any NASA astronaut.

Clear the technological hurdles -- if the bone loss problem isn't solved by then, well, screw it. Take volunteers.

Trade teeth for Mars trip?

[Mordibity]

Sign me up! ;-)

Scientific American

[CTho9305]

sciam had a blurb that mentioned a yet unpublished study on purring and bone growth

No Windows

[Skip666Kent]

Just Flat panel displays that look and feel like windows, showing a static view from the axis or some such.

Hmmm, Vibrators...

[d0a0b]

Whats the possibility of integrating the old vibrating chairs/car mat technology into a tight fitting suit taylored to the individual?

How about..

[Pescatore]

... a combined sleeping chamber and centrifuge?

The Astronuts would lie on its walls so there would not be a problem with the gradient.
When it's time to go to bed you would float into the cylinder strap yourself up and hold on for a minute or so while it accelerated to about 1 G and then you could loosen the straps and go to sleep..
Just make sure they wake you up before they pull the brake...

Easy enough to fix...don't travel in zero G!

[Moofie]

This dragon keeps coming up as one of the major reasons not to explore the solar system, and it's one of the easiest to put to bed. All you have to do is attach the spacecraft to its spent upper stage with a long tether, and spin the whole system like a baton. You can get modest gravities with reasonable (on the order of a hundred or so feet, depending on the mass of the upper stage and the spaceship) tether lengths and angular velocities. The nice thing is that even if the tether were to break, the only thing you'd be losing would be a useless hunk o' metal. The astronauts would of course be less comfortable, but the mission could be accomplished.

If you're interested in this sort of thing, Robert Zubrin's "The Case for Mars" (http://www.marssociety.org has a copy for you) details things like navigation and maneuvering on a rotating platform.

Re:Easy enough to fix...don't travel in zero G!

[pubudu]

All you have to do is attach the spacecraft to its spent upper stage with a long tether, and spin the whole system like a baton. You can get modest gravities with reasonable (on the order of a hundred or so feet, depending on the mass of the upper stage and the spaceship) tether lengths and angular velocities.

How would your alter course, or would you have to start the tether anew each and every time? Considering this thing sounds like a fan with only one blade, wouldn't they have to make numerous course adjustments along their way, during which they'd be in zero gravity? What would be a reasonable ratio of time with gravity to time without gravity?

Re:Easy enough to fix...don't travel in zero G!

[Moofie]

Actually, you can make all your course corrections while under spin. The flight control software can simply be programmed to make a large number of low-impulse burns that net out to the required delta-V. The axis of revolution points in the direction of travel, so the path the spacecraft traces will be a helix. Just needs somebody who's good at polar coordinate systems to write the fly-by-wire algorithms. Non-trivial, but eminently do-able.

And it's NOTHING like a fan with one blade! It'll be asymmetrical, sure, but it will revolve around the system's center of mass, stable, until you fire your rockets to make it stop. Astrogation from a rotating platform might be tricky, but far less tricky than carrying enough fuel to stop and start your spin lots of times. Basically, you'd start the spin once you've done your burn to get into your transfer orbit, and not stop it until you get ready to enter orbit around Mars (or, if you're really brave and strapped for fuel, entering Mars' atmosphere for touchdown directly from your transfer orbit...but that's an awfully risky scenario!)

30hz is not high frequency!

[funky49]

Actually 30hz is not high frequency. 30hz is definately BASS friendly. The lowest tone that is still a sound is 20hz. Hertz is cycles per second, thus 30 cycles per second is indeed quite slow and not a 'high' frequency by any audiophile's book, nor mine.

Why were scientists looking to make sheep with bigger bones anyway?

steve

Re:30hz is not high frequency!

[sinator]

/* Why were scientists looking to make sheep with bigger bones anyway? */

Osso Buco?

Zero G sex?

[Cardinal Ximinez]

On the other hand can you imagine a year of zero G sex?

I assume you mean with a willing partner of the opposite sex.

Re:Zero G sex?

[Anonymous Coward]

On the other hand can you imagine a year of zero G sex?

I assume you mean with a willing partner of the opposite sex.

Nah, I think he was indulging in autoerotic fantasies. . .

Beware the floating skittles from Mission to Mars!

[shiwala]

Of course they're going to be losing teeth...I mean come on, they're taking lots of junk food up there! (Or have we forgotten about the floating skittles scene in the blockbuster Mission to Mars??? :)

Re:30 Hertz vibrations - cats & purring

[Anonymous Coward]

Same thing has been show on injured cats and the effects their purring has on healing the injured limb.

The could high gravity make you grow teeth?

[kaoshin]

If so, maybe old people could all get on a big gravitron ride until their grills get fixed.

Spinning spaceship?

[Sebastopol]

RE: Last line of the article, the part about the spinning ship.

I seem to recall a pen-and-paper calculation demonstrating that simulating gravity by spinning the spaceship would require either: a) a spaceship with a ~1km hull, or b) a hull that would have to spin at unreasonable speeds...

Anyone know what I'm talking about? Any physics majors want a stab at this?

Re:Ant

[John F. Ketamine]

I am so fucking tired of this guy! I am not even concerned with him, it's /. that I'm pissed off about. Are you just going to sit around while this kid does nothing but troll your boards? I mean, there's a serious legitimacy to the idea that AC's shouldn't be allowed at all, but now what about people who are obviously non-stop trollers, and belligerent ones at that?

Can't /. eliminate this guy's ID and/or block his IP? Or are you all a bunch of fucking milquetoasts?

Why don't they just use that star-trek technology?

[pblanton]

Those guys on Star Trek have plenty of gravity on their ships and they don't spin. Why don't we just use that technology?

Duh! Don't those scientise guys watch television?

Re:Blow Jobs

[pblanton]

Yuck!

Where did you find a nasty, toothless hag to experiment with?.. and the more important question...

Why!?!?!?

Images of the Hansel and Gretel witch, naked loom in my mind.

AAAAAAAAAAAAAAAAAAAAAAAAA!!!!!

Will it still be an issue when?

[Phrogz]

It's certainly good to identify such problems and prepare for the ahead of time, but I'm not that worried about this. Science/Medicine are making good progress on preventing problems once they know about them (while IMO progress isn't as hot in the whole fixing-existing-problems domain). This feels like a readily-understandable problem.

By the time we're ready (socially, financially and technologically) to make trips to Mars with such frequency that this is a serious problem, I feel confident that a supplemental drug and/or exercise regimen and/or artificial environment will be available to prevent this problem.

30hz Vibrating backpack

[Zeno_1]

Just make a backpack that does this.

I remember something from a while ago, it was for a car stereo, and it would sit under your seat, and you would hook up an input to it from your stereo. It would be bolted right to the chassis, and when deep bass hit, it shook the car to simulate the 10-30hz frequency range.

It seems like an easy task to put one of those in a backpack, I think the deal was called a transducer, but I am not sure. I looked up what a transducer is, and its an antenna, so theres probably another word for it..

Zeno_1

--------------
I'd rather have my mail delivered by Lockheed than ride in a plane built by the post office department.
--------------

This is interesting..

[mindstrm]

are you serious about those dreams? Because I have them too... not every day or week, but regularly enough.

how about 'DEM apples

[Stalcair]

I have that little chant in my head about the apple a day keeping the doctor away. On a serious note, would eating 'tough' food stall or reverse this low G effect? Because it would keep them regular too! I can just imagine the mess in micro-G... manned space missions would be just like over seas missions of old, where every ship had to carry barrels full of citrus fruits. Funny how that seems to happen throughout history.

Re:Artificial Gravity? Ala 2001 ASO

[Lumpy]

Or just a roataing section.
Not too difficult, and very plausable. The problem is that it doesn't fit with NASA's current spend very very little methodilogy. anything that we sent do mars with people in it had better be the most expensive and over-engineered mechanical marvel the human race has ever created. The problem is that we're trying to get there in a volkswagon bug instead of a Lincoln navigator. and we really need to be bringing the Lincoln.

Rendezvous with Rama

[scheming daemons]

There was a SF novel written several years ago that addressed this very idea, can't remember the author, but the title was "Rendezvous with Rama".

I believe that the physics involved here are valid, but the ship would have to be very large.

Re:Rendezvous with Rama

[shroom]

It's by Arthur C. Clarke. There's also a few sequels.

Look at how much action someone with no teeth gets

[Giant Hairy Spider]

We aren't going to lose our teeth any more than the peacock is going to grow a small, sensible tail.

Obligatory Futurama Reference

[sinator]

"This article brought to you by THOMPSON'S TEETH:

The only teeth strong enough to eat OTHER TEETH."

accel. != delta v ?

[rabidcow]

nice delta-v, but very low acceleration

Wait, I'm missing something here. What's the difference between acceleration and delta v?

I seem to remember that acceleration = change in velocity. What gives?

Re:accel. != delta v ?

[Christopher Thomas]

Wait, I'm missing something here. What's the difference between acceleration and delta v? I seem to remember that acceleration = change in velocity. What gives?

Acceleration is the instantaneous change in velocity (derivative of velocity) at any given time. Delta-v is the integral of acceleration over time (actually of the magnitude of acceleration). For a ship accelerating in one direction outside a gravity well, it will be the total change in velocity (v_end - v_start).

Acceleration is how fast you can change your speed, and delta-v is the total amount you can change your speed by.

Re:accel. != delta v ?

[Anonymous Coward]

ok, thanks.

duh... accel = delta-v/time...

...on the other hand...

[Gakl]

Two modules, connected by a relatively simple and very long tether creates its own problems. a) the aforementioned breakage, and b)if you have the service components--say important instruments, you'd have problems w/ repair. You need to have systems nearby the habitation module in case of the need for emergency repair.
Also, given our current state of rocket technology, we can hardly afford to accelerate for any significant portion of the trip. The trip would take months if not years.

Therefore, it makes more sense for the ship to undergo spin only when the main propulsion module isn't active.

The only thing that seems to make any economic (or practical engineering) sense is to have the vessel constructed in several phases, similar to the ISS. Module 1, crew habitation quarters, life support, and control systems. Module 2, main propulsion, with several disposable sections, other sections meant to be later converted into ground habitation modules, module 3 would be the full lander module, with full facilities for life support, ground rovers, solar panelling, and extensive batteries in case of emergency.

this would lie on opposite end of crew section--all supported by a laticed metal frame with multiple support beam--imagine two arcs, maybe 30 degrees each with supports connecting to a long cylindrical central module. in the connector between crew, lander, and main engine, could be a tube connecting across to each end of the "ship" so that crew could pass from hab quarters to maintain components without needing to leave the confines of breathable atmoshphere.

Additionally, it doesn't seem to make sense to prepare the vessel for a return trip so much as to provision the ship well and make it nearly self sufficient (at least for a number of years) and allow the crew the tools to work off the raw materials on Mars (obviously a bit beyond our current applicable technology).

To return, a vastly trimmed down vessel could be sent. It would necessarily be unmanned--decreases the cost many times...no need to spin, less mass, can simply make it a giant fuel tank, supply pod, connected to a massive rocket. Fast acceleration, and rocket-assisted gravitational decelleration into docking-orbit w/ main rocket frame to merge w/ the frame where the lander module had been. A lift-off module would be dropped to the surface. Transport back to main vessel.
IF you wanted to have mars continually inhabited...use 2 manned transports 2 unmanned "fuelers"
order of launch...1st manned...1st fueler/2nd manned--fueler to arrive first..allowing 1st ground crew to reprovision in preparation for 2nd crew, which would arrive later...1st crew takes the first manned station back w/ the fueler module attached as balast for spin...2nd manned remains in orbit awaiting the return of the 1st manned vessel and 2nd fueler...

Sort of a cyclic multi-stage colonization of mars...?

food for thought...

Re:...on the other hand...

[Kaki Nix Sain]

I like the plan, just have a couple of points. If the fueler ships don't have people, then getting them there fast isn't important. Sending them fast is more expensive than sending them slow. So adjust the schedual to send them before the manned ships, they can still arrive afterwards, that part doesn't matter.

Also, if you are planning to have an actual colony, it would been nice to start throwing supplies on slow trajectories as soon as possible. The gravity wells of the moon and earth can help with this and bring the fuel costs down a bit.

fsck the teeth

[psych031337]

I am bit astonished...

In the german army, some "mission-critical" servicemen (such as divers or snipers) have to get their natural teeth removed and replaced with high-quality implants.

This makes sense in a military point of view: there is one potential risk eliminated, namely that of developing teeth problems during wartime and spoiling critical stuff due to not being 100% fit.

I am sure that certain parts of the US army use this as well. Why not NASA? I suppose an astronaut just having pain in one tooth during that never-ending flight to mars could account for a lot of problems among the crew... Killing for someone's ration of painkillers or something.

Flying there is a big psychological challenge for any individual, so it make sense to have that problem solved...

It kinda reminds me of the ISS crew pestering about their lack of shampoo awhile back.

Hmmm

[Drath]

Tooth loss? Bone decay? This sounds like a job for neil armstrong and other now denture wearing apollo era astonauts.

Gold needs to be worth less than plastic

[G00F]

"If we have access to an asteroid that consists of more metals than we could possible use, don't you think that would eliminate its status as 'precious' or 'valuable'? Gold would be worth less than plastic."

Its eletrical properties are very vaulable and would provide much more use being used as such rather than womens jewerly.

No more alum contacts or copper, all gold. Now that is what I want. Speed things up, less heat, etc.

Spin that sucka

[CatKnight]

The best way to avoid bone and muscle atrophy would be to make a spaceship that rotates, so the astronauts will experience artifical gravity as a result of centripetal force. They could sleep and excersize in this area, while the rest of the ship could be 0 g.

does this imply...

[CmdrPinkTaco]

...that there is less gravity in West Virginia?

Astronauts willing to lose lives

[Anonymous Coward]

So why not teeth? Come on, for the chance to go to Mars and Walk on mars, most of these folk would be willing to lose allot more than their chompers.

Most of them are willing to risk losing their lives just to get into orbit. Many of them would trade their lives to get to orbit or to the moon. So what do you think their outlook on teeth vs mars landing is?

worry

[deathscythe257]

i'm more worried about other bone[s] falling off...

lol

Re:Blow Jobs

[Anonymous Coward]

he found your mom

random text to defeat f1lter this is great listening material I hate the warble

Re:Beware the floating skittles from Mission to Ma

[Legion303]

Those were M&Ms, as the filmmakers pointed out by painstakingly arranging each and every one so that the "M" was facing the camera. (Yes, I know it was CG. Pipe down.)

-Legion

MARS TRIP

[Anonymous Coward]

But when Arnold Schwarzeneger went to Mars to film Total Recall his teeth did not fall out. How about all the people that worked on that film there? Something is fishy here...

Who needs teeth .......

[Anonymous Coward]

When you can just make some gold ones.

Hehe...

[kirbyman001]

Well, it's back to the drawing board for Ben Bova

Re:Artificial Gravity? Ala 2001 ASO

[andymoe]

I have to say, I second the sig...

Re:Why don't they just use that star-trek technolo

[JoeGee]

Someone from NASA should call Rick Berman. He seems to know how to do it. You'll note that we almost never see people floating about on any Star Trek show.

Those folks at Paramount really know what they're doing ...