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NASA Proposes Launch Of Solar Sail Vehicle For 2010
outcast341 writes: "Apparently, NASA plans to
launch a solar
sail spacecraft in the year 2010, according to this press release. The the first trip
will take about 15 years, traveling about 58 miles per second. The sail will be 440 yards
in width, and will be constructed of a reflective carbon-fiber material. 'This will be
humankind's first
planned venture outside our solar system,' said Les Johnson, manager of
Interstellar Propulsion Research at the Marshall Center. 'This is a
stretch goal that is among the most audacious things we've ever
undertaken.'" (Read more.)
And if a mere 15 years from now and using technology that's lapping on the safe side of fringedom isn't enough to make you bite, Joseph Rosenblum reminds us, "Not news, but cool: if you havn't seen it, NASA has a Breakthrough Propulsion Physics Program that is a speculative research division looking into the technologies that will one day enable interstellar travel. There's also a 'Warp Drive, When?' FAQ!"
I don't know about vering course. There's no friction in space, so you don't have a rudder. It would probably keep going in the same direction (away from the sun) but just end up spinning in circles from the force of the impact on one side.
They might be able to have a frontal paracute or something that will eventually let it "right" itself so to speak.
Either way, spinning wouldn't be a problem because the comms dish on it would be desinged to rotate and point towards earth, or have some sort of rockets (pressured gas?) for course correction.
"Trim the mainsail yar land lubber!" belowed NASA.
what if it approached another sun?
Has anyone worked out the maths on this? I would expect it to fall towards the sun (if the sail was taken down), miss, and head away again at approximately the same speed. The sail would be able to give it a good boost especially if it got very close to the sun. It might even be possible to use a nearby planet as a slingshot. This would mean that we'd have to get to a star before deciding where to go next though.
What I find amusing is that the power source that runs Cassini is the same thing that powered the Apollo LEMs. The LEM for Apollo 13 has been sitting at the bottom of the ocean since 1970 without incident or leakage. As usual, the word nuclear spawns fear and stupidity in the ecologically-minded populace.
Don't get me wrong, I think that the environment is worth protecting, but we need to seriously think about knee-jerk reactions to things we're afraid of or don't understand. Cassini presented risk, but it was a risk small enough to warrant moving ahead with the mission.
A magsail using the same power source would embody less risk, as the magsail craft would not employ an Earth flyby to gain momentum.
blog |
With people with a track record of getting things done (Red Whittaker, etc).
Project 339: Solar Blade Solar Sail
Their homepage
The real question is... Will it be using Sendmail??
The chains are broken
Loki is free
Ragnarok is at hand...
Anyone seen the DS9 episode where Captain Sisko and his son rebuild an old solar sail starship? The solar sail catches on nutrino particles which travel faster than light and jumps into warp speed. I'm not sure on the science of nutrinos, or if the carbon sail will catch them or not, but this has potential to get very interesting.
The chains are broken
Loki is free
Ragnarok is at hand...
actually, had something better than the Space Shuttle come along, we would probably have colonies on the moon by now. the space shuttle is one of the biggest wastes (cost per lbs of paload) that we have ever used.
-----
please don't feed the monkey
Why are we paying all these long-haired engineers to study electronics? Mechanical calculating machines are capable of doing all the math we'll ever need.
(Etc.)
The correlation between ignorance of statistics and using "correlation is not causation" as an argument is close to 1.
consider our solar system as a disk spinning, to me it seem like we're sending probes out sideways from the center, have we sent a probe "up" or "down" from our solar system? or how about all of 360 degree's? they talk about passing voyager, does that mean they are sending it the same direction? or are we sending probes towards the center of the universe (origin of the "big bang")?
we have a lot of "sky" to cover
Atticka
No sig here...
I would imagine you can move across the wind, but not upwind.
When photons are reflected from the sail, their momentum is changed. Since momentum must be conserved, the momentum of the spacecraft is changed by an equal and opposite amount.
This means to give the ship more momentum toward the light source ("sailing upwind", if you prefer) you must give the photons more momentum AWAY from the light source. Since that's the direction they're already headed, any reflection or refraction of these photons will reduce their outward momentum.
Pass Voyager? that implies that they are both going in the same direction.
Probably they mean in total distance from the {sun,earth,some other 'fixed' point}, rather than the sail zooming right past Voyager.
Photons of light have zero rest-mass, but they do have momentum. if the area of a highly reflective (>95%) surface is sufficient, most of the photon's momentum is transfered to the sail and can produce incredible amounts of acceleration. the trick is to maximize surface area (for more propulsive thrust) and reflectivity of the sail, otherwise you wind up with too much photon absorbtion which causes the sail to heat up. the straight forward photon or Light Sail is an old concept that, while promising in the near term since the technology is fairly achievable, there are even more promising sail concepts on the drawing board, like magnetic propulsion sails and plasma sails. A really excellent far-term space sail concept is the StarWisp, which uses a very high power laser to produce thrust over interstellar distances. the StarWisp is huge, and so is the laser needed to provide power to the craft over a distance of several light years. But the concept is entirely feasible. Such a craft could reach Alpha Centauri in less than 50 years.
The NY St. Thruway has exits 21, 21B and 21A (in that order... in NJ, there's lots of "Exit 15 (was exit 4b)" kind of signs... pretty funny.
"Where do I turn off?"
"The exit formerly known as 9"
"It's tough to be bilingual when you get hit in the head."
Saw this in local bookstore the other day. Kind of cool coffee table book for nerds.
"Inventions from Outer Space : Everyday Uses for Nasa Technology by David Baker" Random House; ISBN: 0375409793.
I'd give you the amazon order ID but that's crass, and I have no connection with either :)
Winton
I'm sure you're just a troll, but that concept of yours depends highly on where the focal point is. With a solar sail, I think it would be at infinity.
--
Doesn't appear to be the most up to date FAQ.
Example... regarding so-called gravity shielding experiments
These investigations will probably take through the rest of 1997 before they have anything substantial to report one way or another
Welcome to 2000...
- StaticLimit
Much less is spent on NASA than professional sports, and professional sports has negative productivity (wastes time), although it does keep the masses in line.
It's not like a project like this would be more expensive than the Space Plane^h^h^h^h^h Shuttle, which probably 90% of the American public thinks is a real space ship -- it can't even get 5% of the radius of the earth in altitude.
--
Hmm, was thinking kind of along the same lines.
What about dark matter?
So is the propulsion design based (in part at least) on assumptions about the number of hydrogen atoms in inter-solar space?
Thought I remembered an article not too long ago about some of this theorized 'dark matter' being found. Would be interesting if this solar sail vehicle were to encounter conditions that were unknown/unexpected and forced us to change some of our fundamental assumptions about space.
(or not)
If I were them I'd not unfurl the sail until the device was out of the ecliptic or outside jupiter.
You still have to go through the Kuiper belt though.
-Yarn - Rio Karma: Excellent
It ain't going nowhere. It won't even reach 1/2 a light year out (far enough to look for a planet X canidate - a 10x larger than Jupiter or brown dwarf perhaps).
Even if it carried the standard compliement of NASA porn, ain't nobody gonna see it. 'Cept for V-GER maybe...
This is our chance to DESTROY V-GER well before it gets to the 23rd century and is programmed to destroy all carbon-based life forms!!!
Eat your heart our Captain Kirk.
The article says this solar sail could reach speeds of up to 58 miles per second -- or roughly 200,000 mph. A light year is a mere 5.8 trillion miles, so if the nearest star is just 4.2 light years away, we could be there in only ... [tap tap tap] 13 thousand years!
:), but it's more likely to be even longer.]
.. and if there were a mission (a Pluto-Kuiper Express follow-up, perhaps, or an Oort cloud explorer), it wouldn't get us to even the nearest star any time soon. The oldest space vehicle still in use is on its last legs at 23, after all.
... it would be a snap. Right?
(Well, I may be off by an order of magnitude, I threw this together in Excel after all
The fact is that this is a propulsion systems R&D effort, and as of yet there is no actual mission that would use this light sail
We won't be in shooting distance of the stars until we can get travel time down to, oh, maybe a half a century -- the career lifetime of a scientist.
And there's lots of glib comments in the forum about things like, "oh, by then we'll have mag sails!" My boy, when I was 18, I believed in the stars too. I knew that by the year 2000, knew it in my bones, that we would have people continuously living in earth orbit, and probably a moon base too. Sure, I was a realist -- I knew that it wouldn't be a big spinning Kubrickian wagon wheel. That was beyond our engineering. But hey, we had the shuttle, and we could launch one on a weekly basis
----
lake effect weblog
{Network engineer in Chicago--looking for work!}
Science fiction is responsible for conceptualizing a number of things we use every day. The best example of this is probably the satellite, as the people who build them still credit Arthur C. Clarke for coming up with the idea.
:)
Not to mention solar sails themselves (I read several SF stories about them several years ago, all probably written in the 70s). Now if only we had fusion engines: we could make a Bussard Ramjet and reach the center of the galaxy in a few years.
Science fiction is responsible for conceptualizing a number of things we use every day. The best example of this is probably the satellite, as the people who build them still credit Arthur C. Clarke for coming up with the idea.
NASA's scientific research has resulted in the invention of devices we use every day, arguably benefitting this country far more than they cost us. You own a microwave, right?
Finally, look at the page for Breakthrough Propulsion Research. I read it a few months ago and they tell you how much they're spending. It's not much, and the projects they've awarded (small) grants to are NOT pseudo-science and could have applications here on the ground.
As far as medical research funding goes, I work at a federally-funded cancer research organization and I'll tell you right now we're pretty well covered.
Disclosure: I don't have any connection to NASA in any way, though a job there would be the only thing that could get me to move back to Florida.
-jpowers
-jpowers
Hey!
A kilowatt aint negilible (is it? I'm talkin' outa ma ass hea) if you're gonna keep going for a couple of years.
Does anyone have an energy rating for one of those nuclear batteries? For how long can it supply a kilowatt continuously?I'm assuming that if you turn the power off, you loose your plasma gas.
Actually, you can. I forget exactly how... it had something to do with using most of the sail as a gigantic mirror to focus rays back onto a reversed braking sail. The big reflecting sail is of course cut loose, and accellerates away even faster, which keeps the momentum totals equal.
Of course, going to saturn you could just use the sail as an anchor and fish for asteroids to slow you down, or even bleed off speed in the atomsphere.
The principal of the sails is to ride the solar wind. However without an equivelent of water to provide friction in space, it would seem impossible to "tac" (sp?), the manuever used by sailboats to advance in the direction the wind is blowing from (move opposite the direction the wind is blowing). Thus, it would seem you cannot approach a start system because the solar wind from that star would blow you out of the star system again.
- Sig
But your average piece of space debris would only leave a pin-hole. The only problem is to design it so it won't tear once the pin-hole is there.
Someone already brought this up earlier, but even more promising than the Magsail is the M2P2. There are are problems with the Magsail, especially with the size of the superconducting loop--the needed diameter of which has been estimated from kilometers to hundreds of kilometers.
The material requirements for the M2P2 are more modest. The M2P2 uses a magnetic field generated by a solenoid. This field is then "inflated" with plasma. According to Dr. Winglee:
"...a 200-kilogram probe could deploy a magnetic sail of perhaps 20 kilometers' breadth and attain a velocity of nearly 100 kilometers per second using 50 kilograms of gas and about 1,000 watts of power to keep the plasma envelope filled. Making way at that clip, a craft could reach from Earth to Saturn in less than six months. The Cassini probe now on route to the ringed planet, by comparison, will take seven years..."
For more information, take a look at this article from American Scientist, or try this page at the University of Washington.
I believe that in orbit tethers are a hassle and a half because of the coriolis force -- basically both ends are in different orbits, so they want to orbit at different speeds. This of course is hard to do if they are connected by a tether. Add to this any magnetic drag (which was the point of the excersize) and you get a compicated tangle.
However, the more I think about it, the less I see why centripital force doesn't keep tension.
Eh?
I'm sure this is a troll, but what the heck.
: ASTRONOMY /"as-tr&-'lä-ji-k&l/ adjective /-k(&-)lE/ adverb
from M-W.com :
Main Entry: astrology
Pronunciation: &-'strä-l&-jE
Function: noun
Etymology: Middle English astrologie, from Middle French, from Latin astrologia, from Greek, from astr- + -logia -logy
Date: 14th century
1 archaic
2 : the divination of the supposed influences of the stars and planets on human affairs and terrestrial events by their positions and aspects
- astrological
- astrologically
The sun.
-- Sigs are for losers
Since NASA can't even land thier little pokemon things on mars without stuff going wrong, are we going to be ready in 10 years to shoot stuff off that could possibly give away our position and proclaim our technological inferiority to the unknown inhabitants of distant space? Or are there aliens who already have our back?
I almost have to agree with you on the fast, cheap, good choices, except... that there is no reason why you cannot make cheap probes which function correctly. I think that Nasa have been remarkably lucky, up to date with thier sucesses. Obviously this has been in part to do with good engineering, but not entirely. The MPL, to use your example, is unlikely to ever have been as 'good' as Galileo, but it could well have been able to achive 10% of that Galileo did. The faster, cheaper, better motto that NASA has now adopted is a good one IMHO, and should enable them to launch more probes, each with an individual chance of success which is lower than on previous, better funded mission, but with an overall chance of sucess (due to there being more of them) which is greater. However I haven't noticed this happen yet, maybe they have forgotten why they went for the faster cheaper better option, or maybe as someone else suggested all the sucessful mission just haven't been reported. imho what they need to do is get more people in space, coz what people want to see is spacemen, real people bouncing around in space doing stuff... now that's news and science!! anyway jus my 10p'orth
--
Sic Itur Ad Astra
www.gatrell.org
foo
Hey control, why is this thing headed for Jupiter? Oh no!!! it was supposed to be meters...
For all intensive purposes, "whom" is no longer a word. That begs the question, "who cares"?
It seems like a really cool concept, especially as fast as it goes... But what would they do if one of the sails got hit by some space debris like a rock or something? It would really suck if all that time and effort went to waste because of a hole in the sail.
Hrm loving these
At least once more, I think, since you got it backwards. :)
Perhaps one day we can wake up to know that things are actually moving at the greatest pace that they can. Versus knowing that GSA subcontractors are squandering such a massive amount of time as they milk NASA, or that if a wonderful project comes along, government requirements will hold it up for years, and they will finally drop the budget so they can hold the developing countries of the world down in order to hold themselves high.
Please forgive me, but I'm just in a ranting mood this morning. *grin*
And if a mere 15 years from now and using technology that's lapping on the safe side of fringedom
Current Year: 2000
Year of launch: 2010
Good Math.
I also think it's interesting that it'll pass Voyager in 2018. It's like starting a computing problem that will take 6 years to complete. If you start it today, it'll be done in 2006. If you start it 2 years from now, and computers are twice as fast, it'll be done in 2005.
Anyway, thank God NASA is doing something like this. People talk about privatizing the space industry and what not, but there are still things that only NASA can do.
It is a quote from the movie "Pi". Great film...see it if you get a chance. In the movie, the main character did indeed stare into the sun for a very long time.
"That's Tron. He fights for the Users."
All I have to say is it's about time. NASA should have done this years ago. This is exactly the type of project that Americans are giddy to see.
/. :)
NASA must keep the public interested in their ventures to ensure future funding - Aside from the first few space shuttle launches, and recent probe missions, such as Pathfinder and the Eros asteroid probe, NASA hasn't done much to really grab ahold of American's interests and sense of adventure.
What I worry about though is the ambition of the project. Firstly, this should be a mission to Mars, delivering materials needed for future manned exploration, perhaps taking a long a landing vehicle, or probe - something that could immediately send back panoramic pictures:). To deliver a 25-ton payload from Earth to Mars in 1 year, the sails would need to be four square kilometers - just a tad larger than the sails planned by NASA. This would deliver 36 newtons of thrust.
Given a fair bit of chemical fuel, the craft could do much more than deliver a payload to mars - It could drop off the cargo, change course and continue on with NASA's current plan.
This mission should also take place SOON:) 2003 or 2004. Pathfinder only had about 3 years planning. Get cranking:)
Given these objectives, the mission could easily reinvigorate the public's perception of space travel. The idea of using sails in space seems to unreal to most everyone that they love it. To see it in action would be amazing. Hope NASA reads
signature smigmature
- James
What will happen if/when we try to deploy a gigantic sail?
Ciao
----
FB
because this issue (wasting money on `we did it because we can` projects when there are..uh...*slightly* more important problems closer to home that can be solved with just money (and/or a fraction of the technology involved on, say, putting a car on the moon) is as relevant now as it was almost 30 years ago when this song was written (one of the first `rap` songs too...)
Check it out..the lyrics are on the net somewhere i`m sure...
a.
This has been discussed a few times already, but...
NASA's track record isn't nearly as bad as the media would have you believe. The news outlets, as with many other things these days, report NASA failures more heavily than the successes. A probe or ship doing exactly what it is supposed to do isn't considered newsworthy enough for a long spot on the national evening news. A probe or ship that gets lost or otherwise malfunctions, complete with an inquiry and all that rot into why it failed? Now that's news! You'll hear little spots about it for weeks. Just like you'll hear about Columbine for months and months and months, and never hear for more than a second about a school that is doing well.
Things that go right just don't get as much attention as things that go badly.
"That's Tron. He fights for the Users."
I remember reading a short story where the ships had a gravity drag engine (or something) and as the approached a large "well" of gravity, it slowed them down (sounds silly), but you would just use light/solar particles the same way.
As you aproach a star you just slowly slow down as the pressure on your sails increases the closer you got. Personally, I think it's pretty risky. You DO NOT want to stuff it up.
Hows the weather? A bit too warm for my liking.
will be humankind's first planned venture outside our solar system
Was Gallileo's extra-solar journey an accident? How about Voyager?
Am I hugely wrong or this guy knows nothing about previous programs?
I agree. It''s just bad that the PR missions (read "Mars mission") haven't gone well. I hope they will have funding secured in the future too(?).
The first remark is that this is VERY far from a man-carrying mission. The second is to see "Robert L Forward's "The Flight of the Dragonfly" for lots of technical detailsof a hypothetical laser-pushed man-carrying sail. As I recall, the sail was 2000 miles across, and the laser array consumes about 10^16 Watts of solar enegry. Even so, he had to resort to "magical" drugs to keep his crew alive long enough.
He used one method of stopping: cut off the outer part of the sail and use it to reflect the laser beam back onto the central section which carries the crew.
I have heard two others proposed, both in the "The Mote in God's Eye":
1. dump all excess mass and dive very close to the target star. Hope to stop before you fry.
2. charge the ship up to a high voltage and use the galactic magnetic field to spin you around, enter the target system from behind and use the original laser beam to brake.
Antimatter rockets are starting to look like a better deal for interstellar trips.
Steve
If you read the actual NASA press release, the goal for the launch is around 2010 but it will take fifteen years (after that) to go 23 billion miles past our solar system. (They hint that the destination is Alpha Centauri).
--Ben
Slashdot is the modern day equivalent of the "telephone game".
The article gives no information on the planned trajectory. From my 'vast' experience in solar sailing and celestial mechanics (I set an assignment once on solar sail propulsion for a second year university astronomy course) I'll do some speculating. Both light intensity (hence thrust) and solar gravity drop as an inverse square law with distance from the sun - so the ratio is constant. Unless the thrust-to-gravity ratio is greater than one (very unlikely), you can't simply put your sail perpendicular to the sun's rays and sail out of the solar system. In the approximation of circular orbit and small thrust-to-gravity, the optimal orientation is to angle the sail at 45 degrees to the sun's rays, pointing along the orbit (to gain energy and increase orbit size) or back (to decrease orbit size.) If we ever have solar sail tugs making slow interplanetary journeys, this is how they will operate - however, this method can never give you solar escape velocity. To get high delta-v (change in velocity), you need to go close to the sun. I would expect this mission to aim for a highly elliptical orbit to get most of it's delta-v on one or more close approaches to the sun. The last such approach gains sufficient energy to make the orbit hyperbolic and escape the sun. The initial elliptical orbit will almost certainly be achieved by a gravity-assist from a planet - probably Earth or Venus.
Quattuor res in hoc mundo sanctae sunt: libri, liberi, libertas et liberalitas.
NASA has, for unmaned space travel at least, taken a turn in its philosophy. This turn has not been trumpeted by the press. The fact is that some years ago NASA decided, again bear in mind that I'm talking unmanned craft here, it would be cheaper and more effective in the long run to launch cheaply, often, but with a higher failure rate. This is exactly what they have done.
The funny thing is that their failure rate is considerably BELOW what they themselves predicted. They are, in fact, doing a *terrific* job.
Does the press explain this? Not on your life!
Which headline do you think sells more papers?
"Another Mars Probe Vanishes Mysteriously!!!"
( Causing a guy I know to actually think that Martians are shooting them down)
Or,
"Nasa says Lose Rate Still Below Expectations."
" When asked to explain a NASA scientist said, 'We're building quick and dirty, but CHEAP. We're saving the taxpayer money overall, and getting MORE data in the long run. Overall, we're getting far more successes this way than we had dared to hope for."
As for the manned program it really all went to hell back when we dropped the X program for the crash program to the moon.
The crash program did at least end up giving us the only rocker booster we've ever made with a 100% success rate.
By the way, it was designed by one of "our" captured WWII Germans.
" In German, und English, I know how to count down, and I'm learning Chinese, says Werner Von Braun...
One the Rockets are up who cares where they come down, that's not my department, says Werner Von Braun.."
-Tom Lehrer
Shut up brain or I'll stab you with a Q-Tip. - Homer Simpson
If a magsail is feasible in 10 years, then it may take 15 years to complete the launch. No problem by me if it never goes at all.
Stangely, the article never mentions the point of this exercise. Is it
1) Just a "proof of concept" project?
2) Is there some interesting solar system data that can be acquired from a "near but outside" perspective (cause the probe isn't going very far)?
3) What planets, if any, will it fly by?
There most be some interesting science that can be done. However, one must wonder whether the goal of going fast will take higher priority over carrying instruments and telescopes.
___
Uh, the nearest star IS approx. eight light-minutes away.
Some call it SOL, you might call it the sun, and our soon to be friends over near Alpha Centauri might call it the 'Puppy Star" or something similar.
Interested in the Colorado Lottery?
Check out colotto.com
---
Interested in the Colorado Lottery?
Interested in the Colorado Lottery or Powerball games?
check out http://colotto.com
I think they ought to make the sail out of a silicon based material (like a large soap bubble) because it could double as a power source for the space craft (were it conductive enough). A 440 yard (I hope they don't screw up the conversions this time) sail would be able to produce plenty of power for a nice sized probe. Or maybe they could dope the carbon fiber sail with a conductive silicon compound. If they are going to be into massive building projects why not build a large linear accelerator on the moon. With a mile long accelerator and a few watts of electricity you could blast a probe into deep space quite easily.
I'm a loner Dottie, a Rebel.
You may be thinking about the Russian Solar Mirror experiment CNN Article
"...a velocity of nearly 100 kilometers per second..."
:)
It's all very well reaching Saturn in six months but it's a bit of a bummer if you can't stop when you get there
--
Peter
Does a solar sail only work "downwind"?? Or can you it work like a sail in the wind, allowing you to head "upwind" at an angle? I suppose the photons would have to "stick" to one side and not the other... anyone know the answer?
Krispy Cream is people
As a European I suppose it should not surprise me. Most Americans are the descendants of those "malcontents" in Europe who chose to run away from their problems rather than addressing them at home.
So I am not surprised that a nation of "quitters" would try and run away from the problems it has created in its own back yard. (High levels of murder caused by gun ownership and violent video games, poor education system due to low tax rates) etc etc. It seems that most of the problems that the USA has, have been solved in Europe by "common sense Socialism" (not the rabid Stallmanesque variety of Socialism, but something more pragmatic. e.g. the UK's president Tony Blair).
If only those pilgrim fathers had stayed home and given Europe a chance, they would not be so desparate to visit another galaxy now.
Americans cannot run away for ever...
NASA's current budget, adjusted for inflation, is not much lower than what it was in the peak of the Apollo program, but it's mostly wasted on a bloated payroll.
If you are really looking for the reasons for their unimpressive performance you should ask any organizational psychologist. Post-Challenger NASA is a recurring example in all the textbooks.
----
Stop worrying about the risks of nuclear power and start worrying about the risks of not using nuclear power.
I am glad they can count correctly... Now if only they would use the metric system...
Some of us were trained to be polyglots. We speak some Imperial, but mainly think and seriously communicate in cgs. It is not our fault if some people only speak an obscure, off world dialect. Scientists and engineers need to get a babblefish if they want to communicate in Imperial, Sanskrit or Klingon. "Good grief the comedians a bear!"
Even in this information age, where we see not race nor gender, we still must persue hostilities to those who we feel are responsible or are equivilant as their forebearers or perhaps a simple stereotype that propagates across vast oceans and large masses of land.
Beware. The countless entities that bear human form as they press their collective egos upon their world, with all their talents and actions, which as they are, are no more destructive than they are good.
So who are you to separate us into categories and to say that yours are greater than mine? I am proud of my country, but only as much to classify me as a patriot and far less than arrogance. My country has done great things and it will continue to do things that are great. But I will not delude myself in thinking that your country does not also do things that are great.
You think my comments are politically correct? Well they are. As they should be. Because it is the only way for us to coexist in peace. Even that can come to an extreme. As long as we know the truth about ourselves we would no longer be startled when we hear from strangers.
Best Regards,
Everyone.
To tell you the truth I don't know what an analysis of Martian soil will do to effect the way you and the rest of society live their lives.
I CAN, however, list a few ways that that it has effected my life *so far.*
The Transistor/IC/Microchip and hence the Home computer. The PII 400 I'm writing to you with puts more raw computing power on my home desk than all of NASA had *combined* during the Apollo program and is a direct result of that program.
The internet itself, something that many consider the biggest change to the way we live our lives, exists, at least in part, due to the space program. The rest of the responsibility for the internet goes entirely to other "big science" projects.
The WWW and HTML come to us *directly* from the subatomic research people at CERN.
The internet and the WWW alone may end up being worth every penny we've ever spent on big science.
Nomex (tm) fireproof cloth, which saves hundreds of lives every year came directly from the space program.
Carbon Fiber composites. Kevlar. Cheap Titanium.
Modern telecommunications and GPS. Recently a solo around the world sailboat racer was rescued from disaster. Her position could be pinpointed with GPS and her rescuer was notified of her plight by *E-Mail* sent by satellite transmission!
And to wrap it up before I go on and on and on I'll bring up my closing point while directly addressing one of your key concerns.
Great wopping GOBS of big science money is spent on basic medical and biological research. Big science has advance the state of medical knowledge far beyond what anything else ever has, and has saved millions of lives. Much of this research was done directly by NASA. Which is the main thrust of my final point. The money spent by a big project outfit like NASA dosn't ALL go just into the main object of the project. Rockets are the SMALLEST part of the NASA budget. The peripheral research and technological fallout to the public is a just plain HUGE part of "big science."
Could I have told you in advance that a cyclotron would result in the WWW and HTML? No. I'm a scientist, not a psychic. But it did. Other projects will have similar social benifits. I can't tell you what they are yet though, we havn't found out yet, but the record of PAST benfit is huge.
Now we are just begining to synthesis some of what already have. Take Nomex, Kevlar and carbon fiber and *combine* them with big science medical research and you now have millions of people who's lives can be saved by using these to rebuild arteries, rebuild shattered bones, make functional replacement for missing limbs. The list goes on and I'm in danger of not wrapping this up.
Look around you. Think about it.
One more thing: neutrinos are not quite massless, and therefore can't travel at the speed of light. They do get pretty damn close, though. Even so, they carry very little energy and momentum. In most nuclear reactions, the gamma rays carry off much more energy and momentum than any neutrinos involved. So even if you could catch them, they would be of less use than the light for propelling a spacecraft.
>Also, the 'solar sail' phenomenon is based on the fact that the particles of solar wind have mass and thus impart their momentum to the spacecraft.
Not quite. Solar sails use the fact that photons (0 rest mass) have momentum. When a photon hits the sail and is reflected, the craft attached to the sail gains twice the momentum of the photon. The solar wind, on the other hand, is the continuous blast of ionized gas particles ejected from the sun.
Bunsen
Bugrit! Millenium hand and shrimp!
No, and the reason is pretty simple really.
Charged particles are, well, particles.
At 1/3 the speed of light they penetrate the sail and go on their merry way before the sail even has a chance to "see" them.
The sail is opaque to visible light and thus reflects it. For every force there is an equal and opposite force. The sail *absorbs* the photons and then remits them. The reemission creates an opposite force on the sail. Bingo! Just we're looking for.
Particles don't do that. They are, in effect, little bullets to the sail.
Besides, why trade a motive force traveling at the speed of light for one traveling at 1/3 the speed of light?
after the whole mix-up, NASA impressed upon everyone to use metric units as much as possible -- that that should always be the default. in a lot of areas it is anyways. according to my boyfriend (the mechanical engineer), the reason why they have to stick with those crazy units is becasue the manufacturing capability of the whole US is geared towards it. it's not exactly a good thing to design a part in metric, convert the numbers, and hand it over to the machine shop.
/crazy/ in metric. while this isn't a huge problem if you don't need a really, really good tolerance, for space stuff it's absolutely necessary.
interestingly enough, this happens in reverse a lot when something in designed in the US and manufactured in other countries -- the engineers are used to imperial, so that's what they use, and the numbers end up being
Lea
Naw, make that:
And all I ask is a tall ship
And a star to steer her past..
a rover I used to work on will apparently be launched in 2003, and there will be other rover flight missions.
this one's HUGE compared to sojourner, and much more capable.
Lea
True. And since the non-sticky side of Duct Tape is also reflective, if the sail itself is of the reflective type then you don't lose much in the way of propulsion. :)
I actually think there's more to it than just that... Not only are the numbers easier to deal with in that you can divide by 1,2,3,4 easily without having to think, but the units themselves make more sense. The yard is replicated in the metirc system by the meter, but that's the only sensible unit of length. There is no sensible subdivision for measuring people/chairs and similar sized objects (remember that the cm doens't exist in the SI system you *only* have multiples of 10^3) so no inch or foot equivalent, which is a terrible shame.
:)
As for other units, temperature/energy etc. I think that the SI system has much more integration and is therefore easier to remember and use.
Someone said in a post about it being hard for the change to come... well we managed it here (in the UK) fairly easily, we still use pints (which are 20 fluid ozs 4 more than the US one) for beer and milk and pounds/oz's for cooking, miles and mph for distance, but most English people will understand meters and kilos and litres, the easiest change imho has been temp from F to C, it's easy to understand coz 0C is freezing, and we all no how cold that is, and 100C is boiling, which again... I do still retain the knowledge that 80F is a nice hot day 90F is roasting and over 100F means find a swimming pool, but I have all too easily forgotten the other end of that scale... when does it get cold??
Finally I'd like to point out that what we need to do is have a single system of measurement worldwide, and I don't think using this half arsed French metric system is sensible (did you know that the metre is meant to be an exact division of the world's circumference like a 1,000,000,000th, but they used a totally wrong estimate). We also need to use a sensible consistent numbering system within it, and I'd suggest base 12 (well maybe HEX to fit in with 'puters). This would also require base 12 to be taught in schools as a very good alternative numbering system and for two new symbols to be created for ten and eleven, we already have the words in english to cope with base 12... dozen and gross. so 14 would be doz-two and 24 two-doz and 160 gross-doz-four.
anyway.. just some ramble...
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Sic Itur Ad Astra
www.gatrell.org
foo
Oh come on, I can't believe I'm the only person reading /. who actually saw Tron.
I use Macs for work, Linux for education, and Windows for cardplaying.
AFAIK it has been proven that you can pump magnetic fields with plasma. The less the pressure there is on the field, the more it will expand. Therefore the size of the face of your sail grows linear with the energy you put into the field
Such a magnetic field even allows for lateral movements and in combination with swing-by maneuvers you can navigate the whole solar system with such a sail.
A friend studying physics has shown me a detailed article that looked serious.
However this is the best link I could find.
Peole who have treated it in Science Fiction include J. D. Bernal and Cordwainer Smith
I hope NASA make it work. The real problem is keeping the sail from tearing while it unfolds. This seems trivial, but it's not.
For a list of relevant web sites, see here
There are numerous things the government does that are unprofitable yet in the public interest. Running disaster relief agencies, organizing the courts, running the army - these are things that no businessman is interested in undertaking, as they are inherently unprofitable - yet still worthwhile.
This is the mandate of government.
Because you may end up having to live there on day. Given our current environmental track record, there is still a very real chance that we won't get our shit together - that we'll turn the earth into a radioactive parking lot and be forced to live somewhere else.
Medical research is of vital importance to the lives of millions, and is far more worthy of our tax dollars then airy-fairy projects like this.
Hmmm, its not a zero-sum game. NASA's money is not earmarked for medicine, just like the CDC's budget is not available to NASA. There is plenty of venture money and public ownership in the biotech industry - I don't think lack of funds is holding them back.
Is data gathering eg, steering the 'camera' feasible? Other than the fact that @ 250AU a communications round trip would take ~67hrs does anyone have a rough figure for the amount of power and/or sensitivity a transmitter @ that distance would require for earth bound stations to work with. Would the power requirements negate the design criteria of a light fast sail?
BTW - someone here talked about turning it around and sending it back home. You couldn't do that by stopping it and turning around. You'd need the square of the energy used to get it moving to stop the flyer. I'm not a physicist but it seems that a gentle arc would be a more practical way to turn it around.
Fast.
Cheap.
Good.
Pick any two.
The US government has been trying to pick all three and instead has only been picking the first two...
Example. The Galileo spaceprobe is an example of "old" NASA - cost $1.5B, still working now - and doing good science.
The MPL cost what, $150M (i.e. 10% of what Galileo did). And it didn't work.
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Peter
I wouldn't say that. If you don't do research in an area, you'll never discover anything in that area. Remember the first attempts to flight? Flapping the wings didn't work, etc, but large enough fixed wings did...
But then, what are we to expect in a world where physicists have done into raptures about another pseudo-scientific "theory of everything" called superstrings? The brightest minds in physics have been enraptured by a "theory" which purports to explain everything but which cannot be tested. This makes a mockery of the scientific paradigm, and puts superstrings on the same level and religion and mythology.
You forgot the word "yet" again! There are lots of theories out there that weren't proven until years later. AFAIK nobody believed Columbus when he went looking for India. Admitted, he didn't find it, but he found something else: America! The researchers say "We think there is something, so lets go looking for it. Hmm... we don't see anything, but we can prove there is something. Probably we didn't look close enough? ..." and so on. (Did you ever see an atom?)
There is a serious flaw in the way that research is conducted nowadays. We need more accountability from scientists over what they are allowed to research. There are more deserving areas of research which are allowed to languish whilst scientists amuse themselves with the fanciful flights of psuedo-science.
No, what they do isn't pseudo-science, it's more like philosophy. And accountability isn't the right way, either, or we would still be using superconductors that work only at single digit Kelvin temperatures, we probably wouldn't have antibiotics, etc.
If you don't go looking in completely new areas, you'll always have to expand from where you are. Who would've thought that certain insulating materials drop all their resistance once the get below about 90 Kelvin?
Regards, Ulli
Simple things should be simple, complex things should be possible.
Do I have the names right? This is one of the fictional paradoxes proposed in the recent fictional book on WW2 cryptology. That is - if a problem takes 10 years to solve with current technology and 5 years to solve with the next generation of technology which won't be available for 3 years then you can save 2 years of effort by waiting for 3 years and doing nothing.
All you would need is a big assed roll of duct tape and you could patch that hole in a jiffy. There is nothing that duct tape will not fix.
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Check out the beyond2000 story on the subject, posted around the same time ... here
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Read this article: citing that it's possibly headed to alpha centauri.
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Sorry I meant "the power of inertia". Machinery is built with imperial measures, since the tools are imperial, because they build machinery with imperial measures, because...
Et cetera in absurdum.
All opinions are my own - until criticized
It doesn't matter if it's a solar sail, a traditional interplanetary probe, or a space shuttle. If something runs into it, it's pretty much as good as dead. A grain of sand moving at orbital speeds packs enough kinetic energy to do nice amounts of damage to just about anything it runs into.
Mod down posts with a "Free Mac Mini/iPod" sig, they're spam!
I'm pretty sure government contracts are required to be in US units. This really screws over any scientific enterprise like NASA, which uses a real system of measurement.
For example, Massachusetts was considering renumbering all of the exit ramps on the interstates to coincide with the distances (in miles) from the border (N/S, I don't remember). This would make numbering new exits much easier, as they'd simply follow suit. People protested, saying that they liked the exit number as they were. As a result, we still have exits numbered 21B, 42A, etc. I think we even have a couple C's and D's. Americans just don't like the idea of change very much.
Another reason is that Imperial units were much easier to deal with before computers/calculators than metric. Dividing any number by 10 is easy, metric or Imperial. Just move the decimal place. And to divide by 5, just divide by 10 and double it. But Imeperial units divide evenly by both 2 and 3, a pain with metric. (I know, I know, it's easy to divide by three. But remember, we're nerds. Not everyone could read, let alone divide, when the standard was adopted.)
- Ricky
ERROR READING WARP DRIVE
ABORT, RETRY, FAIL, IGNORE?
Good luck to them all.
Ciao
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FB
Just curious.
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Sheesh, evil *and* a jerk. -- Jade
My reasoning is that all the presure (sunlight) is coming parallel to the craft. Where would the friction come from to change directions? It's not a ship in water with a rudder.
The sunlight would still be pushing it away from the sun, all I see it doing is spinning. Think hot-air baloon. They can spin and carry on but end up going in the direction the wind is pushing them. If I stuck a big sail out of only one side, I can't see it changing directions. There is no fulcrum.
Still pretty cool though :)
After all, photons have no mass, so where does the momentum come from?
Then, there was the solar sail race, to mark the 500th aniversary of Christopher Columbus' voyage. Never got past the planning stage.
If it happens, great. If it doesn't, no big surprise. If NASA spent more of it's ever-diminishing money on doing stuff, rather than talking about it, we'd still have a space program WORTH talking about.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
"If I were them I'd not unfurl the sail until the device was out of the ecliptic or outside jupiter."
Actually, a solar sail's power is inversely proportional to its distance from the sun - it might be better to cut in toward the sun at first, then unfurl near mercury. If it didn't fry, it would get one terrific kick.
If you can find the energy to leave the ecliptic from the start, head in toward the sun in a polar orbit, then unfurl and shoot off toward the stars, that'd give you the best of both worlds. AFAIK, there aren't those many asteroids out there, and our best bet it to pretend they aren't there and hope for the best. Of course, the occasional small meteoroid will still hit it, so the sail needs to be made of a material that stops rips but will break away cleanly if hit by a fast-moving object.
Eventually, it's going to hit something, but it will probably be a long time before it hits anything big.
There's nothing wrong with NASA, there's something wrong with us. NASA always knew that all it would take to end our ventures into space was a big disaster. In the 80's, we planned on having space stations and colonies BY NOW. What happened? The Challenger exploded, and people learned that there is actually danger associated with all of this, and that there would be losses. Ever since then, NASA has had to walk on eggshells to avoid being destroyed altogether. Privatization isn't because NASA doesn't want to venture out, and doesn't have good engineers. Some of the finest programmers that I know work for NASA. The privatization is because they don't want to be liable, because people have lost their inspiration to learn and to become better more intelligent people. You just have to look around today to see proof of that. If more of our nations finest die for this great cause, then NASA will die with them, because people just don't care anymore.
There's nothing wrong with NASA, there's something wrong with us. That's why private companies are trying to fill their shoes, and that's why you'll see a theme park on the moon before you see a meaningful permanent research colony on Mars.
Eh...
Space is pretty empty. If you stay away from the close vicinty of planets (low Earth orbit, Saturn's or Jupiter's rings, etc.) then you are pretty much safe from anything larger than a very small grain of dust. Presumably the sail is designed to limit the damage done by such grains (like ripstop nylon).
The best trajectory to get benefit from the Sun depends on the level of thrust that can be achieved. If it is high enough to get well beyond solar escape velocity in one perihelion pass close to the Sun then that is the thing to do. A swing by Jupiter may be the way to get that close perihelion pass (Ulysses did something similar).
If not, then you might as well just spiral out from wherever you are, there's nothing to gain by spiralling out from close in.
Steve
Special Relativity explains how mass and energy are equivalent (Energy=Mass*(C squared)). Well, that's almost all I remember, but since photons have energy (mass), they can have momentum, right? I think that's how it works.
Freedom: "I won't!"
I would be interested to know if they have yet decided:
1. Where they are going to point it, do they have a final destination for it (not that there is much within it's range).
2. What instruments are going to be on it.
"Do you think we could wipe out world hunger forever if scientists figured out how to make AOL's Free CD's edible?"-
I dont see any mention of data aquistition. Is it just going to be carrying the standard picture of people with no clothes, or will it actually have some active components to phone home? I wonder if they could use the sail as a large antenna...
-Yarn - Rio Karma: Excellent
Surreal.. I'm reading this while listening to Pink Floyds 'Set the controls for thge heart of the sun', I don't know if it's appropriate or not.
Anyway, my question is if anybody knows how this is manoevered and set / kept on course? Will it still need giro's and manoevering thrusters?
Do they plan to actually 'sail' it to make course corrections (which would be quite 'trick')?
EZ
-'Press Ctrl + Alt + Delete to log on..'
"Oops, I always forget the purpose of competition is to divide people into winners and losers." - Hobbes
Not that it matters; I'm just curious.
I have no
I'm really sorry but when it comes to the various claims that NASA makes about the future of space exploration I become highly skeptical.
My first point is that the project will be wildly over budget and excruciatingly late. I would estimate that the project will be approximately three times over budget and take three times as long as NASA initially estimate.
Therefore assuming that they start today, we shall not see the first functioning light sail ship until 2030.
In fact the huge budget overspend will mean that the project will probably never be completed and will be cancelled due to the US congress continually seeking to make spending cuts.
Sorry to put a damper on things but this seems to be how NASA operates.
Gimme Gimme Gimme - Karma!
Of course someone will think those numbers are in meters...
All opinions are my own - until criticized
A good idea, but it won't happen. NASA probably won't be launching any more nuclear-powered probes anytime soon. Remember, when Cassini was launched, there was a significant public outcry over its nuclear power supply. The public doesn't like the possibility of an explosion during lauch, sending radioactive shards over half the continent. Even if it isn't likely, the public will raise a bigger stink over it if NASA tries it again.
If you don't think that's very likely, there's been a lot of opposition in St. Louis recently when a plan to ship spent nuclear fuel (i.e., radioactive waste) through the area was proposed. Even with that, although no accident with such a system had ever occured, the public still got the politicians to block it. Something similar would happen if NASA launched another nuclear probe.
But if you could find a more innocuous power source, that magsail could work.
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The real Captain Derivative has a Slashdot ID.
Oh, yeah... Interested in the Microwave? Go to this page to learn about it.
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"To do what ought to be done, but would not have been done unless I did it, I thought to be my duty"
Why should we waste our money on presumptive research, 90% of which will turn out to be a complete waste of time and money?
Because 10% is worth the time and money. Electricity was considered a scientific curiosity for many years. If that was abandoned because it wasn't profitable, then I think the 20th century would have looked a bit different.
Uhm, actually, according to the UN, CANADA has the highest quality of life (for example, living standards, equality etc) in the world. Followed by Sweden,Denmark, Japan...(the order may be wrong). Canada has held this distinction 5 times in the last 7 years, usually falling to 2nd (behind Sweden) when it isn't number 1. I believe the US ranked about 15 or 16, mainly due to the gap between rich and poor and the violent penchant of many of the citizens who did not attend the Million Mom March.
As for God fearing "peace and tolerance" well perhaps you should ask the Lakota Souix (sp?) or perhaps the Beotuks of Newfoundland what they think of your bible thumping "peace and tolerance" - oops can't! The Beotuks were completely wiped out in a mass genocide about 150 years ago because they would not convert to Christianity. There are none left. This is not something we in Canada are proud of, but at least we admit it to be true (PS we haven't broken any treaties we signed with the natives...how about you?).
Now, what was that you were saying...
Never by hatred has hatred been appeased, only by kindness - the Buddha
There's an argument brewing about the logisticity of a solar sail, when 99.99% of us aren't even totally sure that the stars are real. Weve hacked into computer systems to get the knowledge we were deined, why not telescopes? ;)
It's nice to see NASA taking the long view of things, but when you consider the alternatives, it seems a little nuts to be considering building a solar sail now or in the next 10 years.
The better alternative would be a magsail, which should be more feasible in 10 years and will weigh less than a ligthsail.
A magsail would consist of a loop of high-temperature superconducting wire. When a charge is run through it, the magnetic field created deflects the solar wind and imparts velocity to the spacecraft.
Downside is, you have to carry a power source. Upside is, with the weight saved in changing from a lightsail to a magsail, this should be negligible. Use a nuclear-thermal battery like in Cassini (about 72 pounds), fire that probe on a close gravity slingshot around the sun, and as it comes around the direction you're aiming for, unfurl the magsail, power that puppy up, and you're *gone*
(Incidentally, these are used in the book "Encounter with Tiber" by John Barnes and Buzz Aldrin. Don't get scared away by the famous name on the cover...it's a great book, and I've been praying that they make a sequel.
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Has anyone every played with a magnifying glass and twigs, or ants, or your toe? You can do the same thing with a mirror that happens to be slightly concaved, or better yet, flexable so you can change the focus.
With a 440 yard wide mirror you don't even need to be able to get a good focus, at the center you'll have one heck of a powerfull spotlight. You could melt buses from orbit, blind people, blind livestock, start fires... say at national nuclear R&D labs, or zip around the solar system. The solar sail is just sooo darn neat. And all with the power of the sun.
With the materials there talking about, the mirror it's self would be basicly undamageable. If you poke a hole in a tissue, the rest of the tissue dosn't care. Current military anti-satalite weponry wouldn't do anything unless it hit the mirror control systems... and how would it find that in almost 200,000 sqr meters of mirror? Nukes or EMP devices would just kill it dead though.
Dude, solar power rules. When in doubt, take the high ground. -that person.
Man, the artist's conceptions are all wrong. It doesn't look anything like the Arcadia.
This is the problem with the American public. We want practical results NOW. All we seem to care about is the bottom line, with no room for creativity or imagination. Who cares if the research might be useful extremely valuable to us in years to come. Who cares if it is just really interesting for its own sake? This type of research is needed if we are ever going to explore mars or any of the other planets in our solar system. And why would we want to do that you ask? Why would we even think to spend our tax dollars on useless research into our solar system and planets and comets and asteroids? I don't know about anyone else, but that question is so meaningless to me. I have never even dreamed of NOT pursuing scientific investigation of our universe, simply to KNOW what is out there. if not for the future of exploration or space resource development then to satisfy the desire to know a little bit about where we come from and where we are going. Studying the climate and geologic history of Mars in particular could give us clues into our own future and the results of major climatic change. the desire for "practical" research is fine, but pure research is needed to make the real strides in scientific knowledge that has helped our civilization thrive and clutch its way out of the mud of ignornace that we were born into.
I've hijacked the slashdot account of my pet cat (Ella) to say that this article has cheered me up immensely. I'm getting old enough to have cataracts, thankfully fixed by cool 21st century cyborg technology, it's my birthday and I was feeling faintly depressed we don't have colonies on Mars like I fully expected for the year 2000 when I was a kid. Solar sails made my day. I'll likely be dead before the world realises it needs to mine the asteroids ... (sudden descent into Grandpa Simpson mode here)
Ok this is a bit off the record (apologies) but in view of the embarassing hiccups over metric vs Imperial units recently, can anybody tell me why the USA sticks with Imperial units (inches, yards, miles)? I suppose it's just inertia but I'd be interested to hear if there have ever been attempts to move to metric inline with other nations. It sure would make the maths a bit easier for those overworked NASA engineers :-)
Is the USA the only spacefaring nation to use Imperial units or are there others?
I think I saw a TV program in France (at least 4 years ago now!!), and some there ws going to try putting up a solar sail device. I'm not sure if it went ahead or not but they did a good job of convinving me that it was as good as already up there and working. Did any one else here about this or have those voices in my head been at it again.
Time to go to my therapist again I think.
I see two possible explanations:
- Danger of flying junk is only relevant on Earth's orbit
- Chances of the sail getting hit are small due to relative size of the sail (and any number divided by infinity is equal to...)
but still that leaves me wondering...__________________________________________
God did not appoint us to suffer wrath but to receive salvation through our Lord Jesus Christ --1Thes5:9
Ok, Nasa promised things before. But think about it: We face the same quest as Columbus again. We have the chance to visit other areas in space while we're still living, although there won't be people on the space craft.
The comments up to now are in my opinion too pessimistic. Columbus' idea didn't make sense to the spanish king, let's not replay history.
We used this technology to explore our planet over the last 4000 or so years and here are, in our "ultra-modern" lifestyles intending to use the same technolgy to explore the stars. The same stars that they used to navigate those ships by 100's of years ago, and even not that long ago.
This makes me feel like I did when I was a kid. Reading all those sci-fi books and dreaming about the future. I must admit that recently I've gotten a bit "ho-hum" about the whole NASA thing and shuttles and space-stations. I've been thinking that the human race had lost it's exploring drive, with wanting faster computers and our lust for more bandwidth.
But, like I said, I'm a bit of a romantic, and the similarities really apeal to me. Could this be the technology that we use to finally leave this planet and start populating the universe?
Imaging fleets of these things saling out towards distant suns with humans aboard. Establishing space stations around their planets and eventually terraforming its atmoshpere and surface, seeding it with DNA from a planet light years away.
Then again maybe I just read too much of this stuff when I was a kid, but it's still nice to dream about the future.
Who would have thought that NASA has trouble being consistent in their units?
The page on the solar sail craft says "The emphasis of the current research effort is on the interstellar precursor missions designed to set the stage for missions to other star systems later this century."
I'm having trouble deciding whether we're supposed to read this as someone from the 20th century having difficulty learning anything from a 747, or whether NASA is planning on really speeding up the timeline.
Also the fact that we have a rather handy source of photons, ie the sun. At least as long as we are interested in travelling *away* from the sun.
Spyky
Can anyone really answer for me what the net gain of all of these "big science" projects are for us, the general public?
That's easy! Tang.
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"Duane Dibbley?" -- Duane Dibbley
If the sail is made of absorbing material, the incident forces would all be in the same direction -- away from the sun. So then it would just be spinning because the forces are not symmetric w.r.t. the center of mass. If the material is reflective (probably will because you get twice the thrust this way) then once the sail has rotated a little, it will change course. But on average over many rotations it will probably keep going in a straigh line direction. Also there woiuld be the danger of the sail getting stuck parallel to the sunlight and thus getting no impulse. It's solvable though.
..but it never seems to catch on. In high school (8 years ago now) all my math/science classes used metric. Same goes for college. I think most scientific communities use metric now. BUT, the problem comes with everyday use. I am used to seeing MPH on the highway. When I'm going 75mph I know I'm speeding. When you say 75kph, I have no freaking clue unless I think about it. 60C? What the heck is that?? I know 60F is a cool day in a second. People don't want to think about these things - they want to see a number and know what it means instantly. So maybe your "inertia" idea is a good one too. At my college, the cafeteria is called "SAGA". The Saga food service company hasnt been there for 10 years, but every freshman class learns to call it SAGA from the upperclassmen. They tried to force us to stop (Mariott was the company that didnt like us calling them that) but how can you?? hehe, I'm rambling now, but you get the idea :)
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"Every artist is a cannibal, every poet is a thief."
Of course - and they got it RIGHT, century roll over doesn't occur till the end of the year
-- 73 de KG2V For the Children - RKBA! "You are what you do when it counts" - the Masso
Since in relativity momentum and energy are related through the equation E^2 = p^2*c^2 + m^2*c^4, for a massless photon there is a relation between its energy and it's momentum p = E/c, so light falling on the solar sail has a momentum and thus exerts a force on it, pushing it away from the direction the light came from.
I can't remember any more at the moment, it's been a while since I studied thermodynamics at university :)
Looking at the sun isn't harmful, as long as you don't do it for any length of time. Thus my Mum fooled me as a kid by telling me not to even look at the sun - all I dared do was peek, and I thus was not hurt. It's interesting how a false message is often the right one to send (and no, I don't work for M$ marketing division).
"What is freedom of expression? Without the freedom to offend, it ceases to exist." Salman Rushdie
Maybe, when this thing is launched, it might catch a wave of tachyon beam thingies, which then propels it to warp speed, on a course to Cardassia.
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No, I'm not sure what this research will bring us. Maybe new materials, maybe new propulsion methods, maybe new reasons to leave the solar system.
Medical research is fine, but basic research is what gives the greatest benefits... the elctron microscope wouldn't have come about with physics experiments.
I demand a million helicopters and a DOLLAR!
So we can conclude that NASA's century/millenium rollover occurs 2000/2001.
Boy, am I in a sarcastic mode today?
All opinions are my own - until criticized
And all I ask is a tall ship
And a star to steer her by..
This is all well and fine for unmanned probes, but what if they wanted to put people on it? How would they have the energy to return? Would they have to aim towards another star so they could turn around? (They'd have to first worry about slowing down; even if it's thin, it would be fairly massive with a crew compartment, and at 58 mi/sec that's quite a bit of momentum.)
Gates' Law: Every 18 months, the speed of software halves.
...and so more likely to be noticed by any passing interstellar tourists. Maybe NASA could arrange for additional funds through selling advertising space on the sail? ;)