Space Elevator Teams Compete for NASA Prizes

Hugh Pickens writes "The University of Saskatchewan's has the first place climb in the Second Annual Space Elevator Games being held this weekend at the Davis County Event Center in Salt Lake City. Teams are competing for $1,000,000 in NASA prize money. Although the idea of a space elevator has been around for decades, the space technologies needed to support it have yet to be created. The non-profit Spaceward Foundation has hosted an annual competition since 2005 to build a super-strong tether, or get a robot to climb a suspended ribbon. In the robot climber competition, teams have to get their device to hurtle up a 100-metre-long ribbon, suspended from a crane, at an average speed of two metres per second. The climber must be powered from the ground: strategies include reflecting sunlight from huge mirrors on the ground to solar panels on the climber; shining lasers from the ground up to similar panels on the robot; or firing microwaves up at the climber. Qualifying rounds have been taking place all week, and although high winds and rain have caused delays, four out of eight teams have made it into the finals. There are no outdoor climbs today because of bad weather but some of the tether competitions will happen indoors later this afternoon."

Comments

New meaning

[Nosklo]

This gives a whole new meaning to "leaking gas on the elevator"

Re:New meaning

[infidel13]

Geosynchronous orbit = 42,164 km = 42,164,000 m. At 2 m/s, that's just over 244 days to get to orbit. Granted, speeds will undoubtedly improve, but in all honesty, even granting whatever "magic" medium-term advanced technology is necessary to make the cable (i.e. practical nanotubes, etc.), basic propulsion is going to be a problem. Further, that cable is going to take a lot of whatever material it is comprised of. Has anyone ever considered the absolutely, stunningly gigantic capital investment in materials alone? While I applaud efforts to make space travel cheaper, the whole concept of a space elevator is in need of some serious analysis as far as practicality is concerned.

Re:New meaning

[MrKaos]

Doctor Bradley C. Edwards did a study for NIAC who funded his research (when it was still around). This is a summary of his work.

Re:New meaning

[Anonymous Coward]

What's all that got to do with the post you replied to?

Re:I am the prize winner

[Anonymous Coward]

FAILURE

Space Elevator SciFi

[lobiusmoop]

For a blue-sky vision of a future with a functional space elevator, I'd recommend reading Arthur C Clarke's Foundations of Paradise novel.

Re:Space Elevator SciFi

[Omnifarious]

It was Isaac Assimov who wrote the Foundation series books. :-) Arthur C. Clarke wrote 'Fountains of Paradise'. And what is amusing is that you linked to the right book but got it wrong in the text of the link.

Re:Space Elevator SciFi

[lobiusmoop]

Heh, sorry for that, a scifi brain burp :) Mod's are going to murder me for that one....

Re:Space Elevator SciFi

[Anonymous Coward]

Mod's are going to murder me for that one....

I couldn't find the (-1 Murder) mod ...

Re:Space Elevator SciFi

[Anonymous Coward]

At least you didn't misspell "Asimov" as Assimov, like the ass that corrected you.

Re:Space Elevator SciFi

[Iguanadon]

Have you tried logging in?

Incredible space-age technology...

[pushing-robot]

...A winch attached to a solar panel.

Re:Incredible space-age technology...

[Rogerborg]

...that doesn't work if it's windy or wet.

The more I hear about the current state of the art, the more I think that we'll be using quantum teleportation to get things into orbit long before we have a workable beanstalk.

Re:Incredible space-age technology...

[Rei]

I'll second your pessimism. There's really only one real scientific challenge, and that's the tether. We're an order of magnitude from the required strength, and meeting the required strength may well be *physically* impossible. Most economically viable designs call for 100-120GPa tethers with the density of graphite. Yet the strongest *inividual* SWNTs measured so far are only 60 GPa, let alone the strength of tube bundles, let alone the strength of a mass-produceable fiber. And what sort of stronger bonding structure do people expect to find than graphene's SP2s?

These little "space elevator" contests and companies that address everything but the tether always amuse me. I always picture something like:

"Good news, everyone! Progress on my 'Teleportation Shoes' has been proceeding wonderfully. We've developed a shoelace that fits into the loops perfectly. The insoles have been rated as "quite comfortable", and while the rubber for the heel has been stalled by supply problems, we're certain we can get these resolved shortly.

Teleportation will be addressed at a later time."

Re:Incredible space-age technology...

[ozmanjusri]

There's really only one real scientific challenge, and that's the tether.

There's also the construction and materials movement. If we have spacecraft capable of moving an asteroid into geostationary orbit, and putting the initial construction team and equipment on it, chances are they'll be good enough to make the tether redundant.

I have to admit though, I don't even like the concept of a space elevator. Centralised, large scale, multiple single points of failure, untested tech, extremes of environmental conditions; any one of these phrases sends a shiver of fear down a reliability engineer's spine.

Re:Incredible space-age technology...

[Anonymous Coward]

Climbers are engineering. Tethers are science. Small university teams like these have a decent chance of coming up with a good climber, but basically none of making a workable tether. That research is paid for by grants, not competitions.

Prizes are actually a real motive

[zukinux]

Those kinds of prizes in different kind of things to achieve actually do sometimes make things possible. Unique group of smart people meet in-order to think how to get the prizes money while in the more generic point of view, human achievements are made.
So I actually support any kinds of money prizes, and I agree to accept money prizes for my /. comments. :)

Williamsburg does not need a space elevator!

[Morky]

WILLIAMSBURG DOESN'T NEED A SPACE ELEVATOR! The Space Elevator Will Mean: Less Parking, Weird Ribbon Thing, Constant Loud Whirring Noise, Increased Space Elevator Truck Traffic. Developers have submitted plans to build a massive space elevator in Williamsburg! This monstrosity, completely out of context with existing development in the neighborhood, will be accessible only to the wealthy, forcing thousands of average Williamsburgers from their homes and live-work spaces! Jobs the elevator will generate (operators, repairmen, astronauts) are certain to go to non-residents! Don't sit idly by and let this elevator cast its impossibly long, cold, and very narrow shadow over our homes! CALL 311 AND TELL THEM 'I JUST DON'T NEED THIS SPACE ELEVATOR!'

Re:Williamsburg does not need a space elevator!

[confused one]

Nimby. I say we build it in neighboring Newport News. Then we'll get the tax revenue and your mornings will still be subject to the "impossibly long, cold, and very narrow shadow over [your] homes!"

Bwahahaha ---evil laugh

Re:Williamsburg does not need a space elevator!

[moosesocks]

I think he's referring to the Williamsburg in Brooklyn, NY instead of the one in Virginia. Specifically, the criticism relating to the development of the Atlantic Yards project, which has been opposed by just about everybody apart from the politicians and the developers themselves. Criticism of the actual project aside, there were also some very valid issues raised over the enormous public subsidies going into the project ($2 billion plus any infrastructure improvements necessary, which is insofar an undisclosed amount), given that certain agencies of the city are running Billion-dollar deficits. The entire project reeks of pork.

On the other hand, if they built it in Virginia (a much more sensible idea because it's closer to the equator), they wouldn't be able to send any more than 3 astronauts up in the capsule at a time. Williamsburg is one of the few cities in the US to have retained its "Brothel Laws", and still actively enforces them against tenants the city deems "undesirable" (eg. poor people and college students)

I'm sure the Williamsburg heat and humidity would be hell on the tether (and the tethernauts) as well -- the Hampton Peninsula, and most of Virginia for that matter is chock full of beautiful, fertile land with a decent climate; why the colonial settlers chose to land in Jamestown, and then move to Williamsburg (essentially a swamp) absolutely boggles the mind. Being there in the summer sucks.

Re:Williamsburg does not need a space elevator!

[confused one]

I think he's referring to the Williamsburg in Brooklyn, NY Oops, my bad.

On the other hand, if they built it in Virginia (a much more sensible idea because it's closer to the equator), they wouldn't be able to send any more than 3 astronauts up in the capsule at a time. Williamsburg is one of the few cities in the US to have retained its "Brothel Laws", Another good reason to build in adjacent Newport News! Apparently, we don't care :P

I'm sure the Williamsburg heat and humidity would be hell on the tether No worse than as if they built it where they PLAN to build it... on the equator. Most likely on the equator on a floating platform in the Pacific.

why the colonial settlers chose to land in Jamestown, and then move to Williamsburg (essentially a swamp) absolutely boggles the mind Most of Hampton Roads fits that description, being low lying sedimentary land. Old Williamsburg is inland (slightly) of Jamestown.

Re:Williamsburg does not need a space elevator!

[Grishnakh]

On the other hand, if they built it in Virginia (a much more sensible idea because it's closer to the equator),

My understanding is that is wouldn't work for the elevator to be built anywhere but right at the Equator, or very very close to it.

Re:I am the prize winner

[larry bagina]

While he did fail it, in all fairness, this is NASA we're talking about.

...we're still doing this?

[Prius]

I've been on slashdot for a few months, and I'm kind of wondering why we're still doing these kinds of things. We appear to be perfecting the technology for this and we'll be able to make a space elevator in 5-10 years. Graphene oxide super paper, that radiation-absorbing mineral thingie, nuclear power, etc. all make this possible.

Re:...we're still doing this?

[dbIII]

We appear to be perfecting the technology for this and we'll be able to make a space elevator in 5-10 years

That's what the confidence tricksters want you to believe. That materials scientists meanwhile are trying to make that unobtainium but still have no clue when.

The bellhop shuffle

[Lotharjade]

So when do we hold the contest for the best lift operator? Follow this up with a good old fashioned bellhop challenge.

Do the lift operators get to join the Astronauts union?

Re:Help!

[larry bagina]

roll her over and try the other side.

elevator music for 4 months straight

[Anonymous Coward]

In the robot climber competition, teams have to get their device to hurtle up a 100-metre-long ribbon, suspended from a crane, at an average speed of two metres per second.

they've got a long way to go, at 2 meters per second it would take a little over 4 months to get to geosynchronous orbit. imagine the effects of elevator music on the human mind after 4 months of listening to it.

Re:elevator music for 4 months straight

[flyingfsck]

Worse, don't get stuck in that lift with a lady of leasure...

Re:elevator music for 4 months straight

[Anpheus]

As silly as that is, these robots are in fact accelerating upwards at 1 gee with an 'initial' speed of 2m/s. So if you managed to get 1.01 gees for four months their end velocity would be over 1000 kilometers per second.

The fact that the robot can climb constantly from ground-based energy sources is the goal. Acceleration at 2 gees (double the force) would get you from ground to geosync in 48 minutes.

I can stand elevator music for 48 minutes if it means I get to go to space.

Re:elevator music for 4 months straight

[Anpheus]

P.S.: For a silly example, if they obtained only 1.05 gees up, that is they would counter Earth's pull and add an additional half meter per second squared, they would get from the ground to geosync in only a few hours.

http://www.google.com/search?q=sqrt%282*42164+kilometers%2F%28.05*g_earth%29%29

Re:elevator music for 4 months straight

[timmarhy]

um, they are moving at 2m/s, not constantly accelerating at that rate.

it's still going to take this thing 4 months to get into geosync.

why all this bullshit with laser beams and microwaves? why not power it from a circut printed on the cable? is there some limitation on weight doing so or have they missed the blindingly obvious in their pursuit of the most "clever" solution.

lastly, this is all a waste of time until they have a material they can make the cable out of - and if you say carbon nano tubes i'll stab you in the eye with a pencil, they haven't produced any sizable object from nano tubes.

Re:elevator music for 4 months straight

[Loke the Dog]

The thing is, the tether would be incredibly thin. At the same time, it would be extremely long. Even if it's made of a very conducting material, you simply couldn't send much electricity through it, it would offer too much resistance. You could make it thicker, but that would also mean heavier.

Re:elevator music for 4 months straight

[Fjornir]

lastly, this is all a waste of time until they have a material they can make the cable out of -

Waste of time? Only if it happens that a material suitable for making the cable out of is proven to be impossible or another technology obviates the need for it. Until then this would best be described as time-saving (think: predictive branching and parralellism).

Re:elevator music for 4 months straight

[foniksonik]

4 months eh? How many months are there between Shuttle launches or even regular launches? 4 months would actually be reasonable if they were carrying a big enough payload, say 10 satellites that could be 'launched' from the end point by simply detaching from the carrier and using their own thrusters to navigate to their own unique positions, maybe delaying each detachment by a few hours so they could deploy to different points in the orbit path.

Re:elevator music for 4 months straight

[timmarhy]

ah yes very true, you can't conduct electricity that far.

perhaps floating generators at set intervals? there has to be a simpler answer then freaking laser beams.

Re:elevator music for 4 months straight

[timmarhy]

"making the cable out of is proven to be impossible or another technology obviates the need for it"

huh, thats some back to front logic there. what your saying is lets invest time and money into building the robot before putting the effort into making the thing the robot needs to climb, and just hoping to hell the cable issue sorts it self out.

It'd make a hell of a lot more sense to know the cable is even possible before giving away million dollar prizes for the robot.

Re:elevator music for 4 months straight

[Fjornir]

It'd make a hell of a lot more sense to know the cable is even possible before giving away million dollar prizes for the robot.

No. Not really.

A million dollars is chump change and you (should?) know it. None of the labs involved in this are competing for the prize money. The reward they seek is their name having been listed as participating, or having won the purse. Even if the cable is proven impossible then the engineering efforts committed to having participated aren't simply wasted -- if you can't think of even a half-dozen ways they might be applied you should probably consider giving up engineering and taking up a career in accounting or some such.

Re:elevator music for 4 months straight

[Anonymous Coward]

How exactly is hundreds of magically powered generators simpler then a laser beam? Shine light on a power collector. Until someone finds a way to store power at a density that allows a climber to hold its own power supply you aren't going to get simpler then shining a beam (light, laser light, microwave, whatever) at a specialized solar panel.

Re:elevator music for 4 months straight

[timmarhy]

it's simpler because it actually works.

how much power do you really expect to get from a beam like that? the answer is fuck all. definately not enough to move any significant weight.

and i didn't say they were magiclly powered dipshit. you could suspend solar array's via large helluem balloons. obviously you read generator and assumed i meant gas powered when in fact generator could be anything that generates power.

Re:elevator music for 4 months straight

[Anonymous Coward]

Nothing says the robot has to be the *only* robot on the tether during the ascent. You could start one today, start another tomorrow, another the next day, etc. Then you have a whole series of robots moving up the tether. So you wouldn't have to wait four months for another launch window. Still would take four months to ascend, but at least you don't have to wait eight months.

Of course, you couldn't have robots going up and down at the same time, so you'd either need a second tether to have robots coming down on, or a secondary return method (orbital descent freefall or something).

Re:elevator music for 4 months straight

[khallow]

why all this bullshit with laser beams and microwaves? why not power it from a circut printed on the cable? is there some limitation on weight doing so or have they missed the blindingly obvious in their pursuit of the most "clever" solution.

What bullshit? Putting circuits in your cable robs it of strength. Current designs don't have the margin. As usual, the "blindingly obvious" is so only to the ignorant. As a rule of thumb about things that you aren't an expert in, if there's something obvious that isn't done, then the most likely explanation is that you don't understand the system well enough, not that someone is being too clever.

Re:elevator music for 4 months straight

[ozmanjusri]

or a secondary return method

That one's already been tested.

They're looking for volunteers for the human trials, if you're interested.

Re:elevator music for 4 months straight

[Rakishi]

The fucking elevator is 35786 km long, consider that for just a bloody second. Helium balloon? There isn't even an atmosphere for most of the things length.

Re:elevator music for 4 months straight

[pushing-robot]

The earth's gravity extends far beyond its atmosphere. Balloons won't get you to 40 kilometers, much less 40,000 kilometers.

Currently, microwave transmission is the most practical method in terms of efficiency and availability. Microwave beams have thus far transferred many tens of kilowatts over many kilometers at 80%+ efficiency and could be scaled up to meet any power need. There are some issues that still need to be resolved, and there are plenty of other technologies that show (possibly more) promise, but if a space elevator was built today it would probably be powered by microwaves.

Re:elevator music for 4 months straight

[MarsDefenseMinister]

That's a good problem to have, because we have good solutions to it. Keeping a long pipeline filled (even 4 months) so that it's constantly delivering a stream of material to orbit is trivial. 4 months to orbit won't reduce the utility of a space elevator very much.

Re:elevator music for 4 months straight

[Rakishi]

Depends on what the primary cargo is, there are very few satellites launches each year for example and there are only so many sats that you can shove up there before it becomes a cluster fuck. Four months is too long for sending humans, tourists up, and you will need to be sending people up quite a bit. Specific people are the only thing you can't, with time, make more cost effectively in space as they're unique. Space elevators are a great way to build an infrastructure in space but you still need something to use it.

Re:elevator music for 4 months straight

[MrKaos]

Maybe that could be the 'express' elevator.

Re:elevator music for 4 months straight

[alder]

teams have to get their device to hurtle up a 100-metre-long ribbon, suspended from a crane, at an average speed of two metres per second

at 2 meters per second it would take a little over 4 months to get to geosynchronous orbit

2 m/c is an average speed over 100 m climb, which starts at 0 m/c. Assuming constant acceleration to the mid-point and the same (only for simplicity ;-) deceleration it should take a little over 8 hours to arrive at the intended destination... You may find it acceptable if you read a book instead of listening to the music :-)

Re:elevator music for 4 months straight

[Anonymous Coward]

2 m/s is actually pretty respectable, when you remember that the effects of gravity decrease as you go up. 2 m/s at ground level corresponds to a specific power (power per unit mass, a bit like the power to weight "ratio" of a car) of about 20 W/kg. With decreasing gravity, the climber can ascend faster and faster as it goes up.

The specific orbital energy of geosynchronous orbit compared to an object sitting on the ground is about 60 MJ/kg, so with a specific power of 20 W/kg, it would take about 3 million seconds, or about 1 month. That's still too long, but only a factor of 4 off from a feasible climber design which would require only a week to ascend to geosynchronous orbit.

This improvement by a factor of 4 is a lot for some engineering projects, but for a space elevator, it's a sigh of relief compared to the improvement (in tensile strength) by a factor of ~30 needed for the tether material.

Re:elevator music for 4 months straight

[rbanffy]

"there has to be a simpler answer then freaking laser beams."

Maybe a rocket? ;-)

Re:elevator music for 4 months straight

[MarsDefenseMinister]

You're still not thinking the right way. You're thinking about people visiting space, and saying 4 months up is way too long for a vacation. I'm thinking of people living in space, so they won't be riding the elevator constantly.

Re:elevator music for 4 months straight

[Rakishi]

Except that there is pretty much nothing for them to do up there. Tourism is about the best way to raise public desire and money for more space infrastructure. Also four months means you need to not only lift up a person but long term life support food, water recycling, emergency facilities, stewards and probably other things.

Re:elevator music for 4 months straight

[MarsDefenseMinister]

There's nothing much for us to do down here either. Most of us work at meaningless jobs, doing nothing important at all really. We sell stuff to our neighbors and buy stuff from our neighbors. Read Ecclesiastes and see.

If you can get a bunch of people living on the moon permanently, providing some product or service, then the Earth Moon system will be self-sustaining, and the people on the Moon will have as much purpose as people on the Earth.

Nothing to do. Bah. If you've got 25,000 people living on the Moon, they'll have just as much to do as 25,000 people living in Marble Falls Texas.

Re:elevator music for 4 months straight

[afxgrin]

The next generation of elevator music will be internet streamed rider selected music.

Otherwise it'll be music that makes you think about space.

Re:elevator music for 4 months straight

[LifesABeach]

Just a thought. In considering the economics of ion drives and weightlessness, wouldn't it be more useful to have "Space Tugs" remove the containers from the ribbon? That way more containers could be put into the rotation for elevator access. Also, Mr. Clark suggested embedding an electrical conduit in the ribbon; It still makes sense today.

Re:elevator music for 4 months straight

[Anonymous Coward]

Accellerating at 2Gs for 48 minutes on a wheeled ribbon climber ? .... you must be clearly smoking something ...

Screw

[inKubus]

I wonder if you could use a screw. I wonder what the momentum would be on a 22,000 mile screw? What would the torque required be? Or could you use a long two-way cable with a pulley at the end such as those on a ski lift? What about helium or hydrogen? When the air got too thin to provide much lift, the hydrogen could be burned in a rocket or fuel cell or something else. What about a sterling engine? Couldn't you fly the far end out to 44000 miles, and use the thing on an incline as the earth's rotation pulls it around to the tangent?

Re:Screw

[Anonymous Coward]

I wonder what the momentum would be on a 22,000 mile screw?

I don't know the scientific answer, but I'd like to be the one to gather the emprical evidence with Jessica Alba, pls.

Re:Screw

[Nazlfrag]

I like the pulley concept, it just requires twice the length of cable. You would also need a means to keep them separate so they don't slam into each other and to stop it twisting. The benefits would include having a fixed point to apply power, being able to analyse the integrity of the loop as it passes the ground station and perhaps being able to lock one half of the ribbon while repairs are conducted on the other half.

Re:Screw

[Jeremi]

I wonder if you could use a screw.

I think I speak for all of Slashdot when I say yes, we really could -- and thanks for bringing up such a painful subject.

Why can't they be self powered?

[zogger]

Why do the elevators have to have "beamed power" to them, when they could be self powered like every other "going into space" craft? Why this unusual criteria? To save weight? Who cares! Once they can make carbon nanotube space tethers, they can also make similar extremely lightweight structures and most likely have advanced electric motors also using some magical "nano" tech (might as well stay consistent with nano) and highly efficient nano solar cells. Just run the dang things during the day, park them for awhile if it becomes night wherever they are on the tether, then resume the next "morning".

Re:Why can't they be self powered?

[Prius]

Carbon nanotubes are oudated even before they're new. Superpaper is better. Also, if you've ever tried a spaceflight simulator such as Orbiter, you know how hard it is to lift any weight into space.

Re:Why can't they be self powered?

[Rogerborg]

Meesa wanna haul fuelsa insteada payload. Takesa twicea longa!

Re:Why can't they be self powered?

[vertinox]

Why do the elevators have to have "beamed power" to them, when they could be self powered like every other "going into space" craft? Why this unusual criteria? To save weight?

Because if the craft could carry its own power supply it might as well be a rocket. The energy required to get into orbit includes its weight in fuel which means you've got to get more thrust which means more fuel which means more requirement in thrust. There is a break even point (obviously), but if you could just haul the cargo up without the extra weight of fuel then you've saved yourself a bit more energy used for the lift which results in an exponentially smaller amount of total energy required.

I suppose they could use complete solar energy rather than "beamed power", but if someone was truly going to get a cost efficient space elevator it would still days a long time to get to cargo into orbit which might last a few days which means you'll have to go through a few days and nights. Of course you could put battery packs on the space elevator for night travel, but again your adding extra weight.

Re:Why can't they be self powered?

[Anonymous Coward]

Why not use electricity.
2 super conductors on the face of the strip will let you use very efficient motors.

Re:Why can't they be self powered?

[Anonymous Coward]

What about the tether being lined with solar arrays in order to deliver power through some conductive strip in order to deliver power to the climber?

Re:Why can't they be self powered?

[camperdave]

As was pointed out elsewhere, the climber would take four months to get to geosynchronous orbit. How big of a gas tank would be required to fuel the climber for four months? How many batteries would it take? The only solutions are nuclear, solar, and powering it from the ground. Solar would only work during daylight hours and if you go nuclear, you might as well just do gas core nuclear rockets. Also, you'd get all the NIMBY naysayers protesting your climber. That leaves powering it from the ground.

Re:Why can't they be self powered?

[ShieldW0lf]

Rockets are the most brain dead way to send things into space, it ought to be illegal.

You want a Hollywood version of how space travel ought to be done, take a look at the Marvel movie The Hulk. The scene where the pilot flies right up to the edge of the atmosphere, and a relatively slightest nudge from the Hulk pushes the plane into space.

Imagine the same scenario, except with the plane supplying the nudge, and another spacecraft waiting outside the atmosphere to receive the package that is hurled across the edge of the atmosphere into space.

That's how we should be doing space travel. Large planes with huge wingspans that generate enormous lift and act as a high orbit launch platform.

For such a smart bunch of people, NASA sure have been taking a stupid, dangerous and wasteful approach to space travel all these decades. I think it's driven by shady back room deals with the fuel industry, personally.

Re:Why can't they be self powered?

[darkwhite]

Well, two things come to mind... one, since they're going to be climbing along a very thick cable already, why not attach power lines to the cable? The obvious problem with that is 35000 km or however long it is to geostationary orbit incurs giant, if not prohibitive, transmission losses in the power cable. A gas pipeline would work, though it obviously would need pumping substations since no pipeline will hold the pressure of a 35000 km tall pipe of fuel... the substations would in turn make it tricky to achieve good speed for the vehicle on the cable.

The other thing is, why not use a nuclear reactor to power the climber motors? A climber is a much more controlled environment than regular spacecraft, it can jettison the reactor in a reentry capsule if things go wrong. Cooling is tricky but probably possible with either big radiator panels or jettisoning superheated coolant. I really can't think of any compelling argument not to use a reactor here.

Re:Why can't they be self powered?

[Karrde45]

Getting into orbit isn't about altitude, it's about velocity. Run the numbers for a massive lifter. You might gain 5-6 miles worth of altitude, and less than Mach 1 velocity. That still leaves you needing a lot of acceleration to make orbit. It's nice for Spaceship 1, which is only suborbital. It's even the chosen approach for Pegasus, which puts some small stuff into orbit. Ultimately, for small craft it is marginally useful for avoiding a few troublesome parts of lifting off from the ground, but such an approach is useless for large launches.

Re:Why can't they be self powered?

[Anonymous Coward]

You're actually a fucking idiot. Hollywood physics? Are you shitting me? So fucking what that I can 'nudge' a payload into 'space'; that fucking thing is falling right back down to the ground. It's not like gravity ends just because suddenly you're in space--you dumb fuck.

But... but... we'll catch it?!!?--you say? Catch it? F=MA? It's still the same fucking amount of enery you dumb twat. You've still got to accelerate the mass to orbital velocity. You sure didn't do that in an airplane in the upper atmosphere without a bunch of rockets--the only difference with NASA is they cut out the (wasteful) middle man and stick to what does the work anyway.

And before you say the 'catcher' will donate the energy needed to get the payload into orbital velocity--that energy got there somehow to begin with--either a certain mass was boosted up to orbital velocity, or a certain mass was boosted well past orbital velocity. In space, that's a rocket.

So before you blow your fucking wad on having the Hulk orbit our shit for us instead of NASA, reinstert fucking brain, take High School physics, and/or shut the fuck up.

Re:Why can't they be self powered?

[timmarhy]

WTF?

i see NASA's mistake now, they didn't hire YOU to plan their space program for them! fuck me think of all the bucks we could have saved! instead of using actual science, we could have sat your ass down to watch hollywood movies and solved all those pesky problems like radiation and gravity

And obviously it's the oil companys. those bastards making money off all those rocket luanches, fuck them for supplying us with fuel!

seriously though, what are you smoking because i want some? the hulk doing space launches, oil company conspiracies... sounds like some good drugs you got there.

Re:Why can't they be self powered?

[ShieldW0lf]

So, what are you saying, Mr Wizard?

Are you saying that you think that the impact of friction involved in ploughing through the atmosphere to achieve that speed is irrelevant?

Are you saying that the fuel you save utilizing conventional lift to reach the top of the atmosphere instead of using rockets is irrelevant?

Oh, are you saying that gravitational pull at ground level is the same as it is in the high atmosphere?

You think throwing out Newtons Second Law of Motion and swearing a lot makes you sound smart buddy? It doesn't. You sound like an idiot.

The most fuel is consumed attempting to overcome the higher gravity at earths surface, which is 9.78 meters per second per second down near the equator and drops in a non-linear fashion with distance, and ploughing through the earths atmosphere, which generates drag and heat. Which also causes the explosions that plague rockets.

The way of the future is exactly as I have described it to you. It's so obvious that everyone in the private sector who is attempting to enter the arena of space flight has chosen this approach, including SpaceShipOne, which is functionally demonstrating the concept.

Next, we will see space assembled ships that cannot and will never fly within an atmosphere or be forced to bear their own weight, which will resemble nothing ever built before.

Why don't you try going to high school in a country with an education system next time.

Re:Why can't they be self powered?

[khallow]

The way of the future is exactly as I have described it to you. It's so obvious that everyone in the private sector who is attempting to enter the arena of space flight has chosen this approach, including SpaceShipOne, which is functionally demonstrating the concept.

Rockets and partially reusable rockets. That's what everyone is building right now. SpaceshipOne was a rocket launched from a mobile launch platform.

Re:Why can't they be self powered?

[khallow]

To save weight?

Yes. BTW, anyone who makes a working space elevator is going to have to worry about weight. Second, why would we be satisfied with just running climbers during the day and limit ourselves to power intensities of 1300 W per square meter otherwise? That cuts down on cargo throughput for the space tether. Makes no sense to implement unless you can't do beamed power for some reason.

Re:Why can't they be self powered?

[ShieldW0lf]

Flat out wrong.

http://www.richard-seaman.com/Aircraft/AirShows/SpaceShipOne2004/

From the article:

The White Knight drops SpaceShipOne when they reached an altitude of about 50,000 feet (15 kilometers), and it takes 30 or 40 minutes for them to reach this altitude. Along the way they levelled out for some time while they checked all of the onboard systems.

PHOTOS

As they spiralled higher above the desert, it became harder to even see where they were; eventually, though, they got high enough for contrails to start forming. Finally, around 7:50AM and 47,000 feet (14,250 meters) the White Knight released SpaceShipOne, which glided for about 10 seconds then lit its rocket engine.

So yes, they use a rocket in the second stage, but describing it as a "mobile launch platform" makes it sound like an aircraft carrier. They used conventional lift to reach almost to the top of the stratosphere before firing off the rocket.

Re:Why can't they be self powered?

[ShieldW0lf]

There is a good article presenting the contraindications against rockets and a number of currently being investigated alternatives (including the beanstalk) here:

http://www.acceleratingfuture.com/michael/blog/?p=178

Another concept mentioned in the article is something called a "Space Pier", which I've always believed will eventually become the standard for shipping freight that can handle very sudden accelerations.

When I was a kid, I conceived it as a coilgun embedded in a mountain range with a line of superconductive electromagnets that would fire things into space like a bullet, but this guy J. Storrs Hall, works on the CRN Global Task Force, he proposes a 100km tall structure built on legs with an electromagnetic linear accelerator on top. Same basic concept, and I think it will eventually be demonstrated to be optimal for the appropriate cargo.

Re:Why can't they be self powered?

[dbIII]

If the material used will be carbon nontubes then they are highly conductive in the high strength direction. All this weird broadcast power really makes it look like a scam since the losses of transmitting even a well collumnated microwave signal are going to be a lot more over long distances than line resistance in carbon nanotubes.

Re:Why can't they be self powered?

[Rakishi]

People really don't like nuclear reactors for this sort of things, mostly the whole crashed into ground at terminal velocity and spills it's contents thing. Baseless paranoia mostly but that's people for you.

Re:Why can't they be self powered?

[Rakishi]

Except that the current design is many such relatively short tubes glued together, that would probably add a lot of resistance. I'm sure there are also problems of having such a large circuit interacting with the atmosphere and other such things.

Remember that while you can dump as much energy into a beam as you want with little ill effect on anything you care about, doing it to a cable will cause it to heat up massively from the resistance.

Re:Why can't they be self powered?

[timmarhy]

correct me if i'm wrong here but spaceship one didn't make it into space at all?

also, your space pier idea... what kind of cargo are you expecting to survive the same g's a bullet experiences?

Re:Why can't they be self powered?

[Rakishi]

To be blunt you're an armchair physicist/engineer and an especially bad one at that. Not only do you not even understand physics (which most armchairs, unlike you, actually do understand) although like the rest of your kind you don't understand the realities of engineering for large projects either.

The highest altitude an airplane can sanely go to is say 20km, a hot air balloon can go higher but they have a very limited payload capacity. Spaceship one got detached at 15km for comparison so I'm being quite kind here, in your favor. Now let's look at some actual numbers, something I assume you're incapable of doing on your own due to lack of intelligence despite the trivial difficulty of it.

The most fuel is consumed attempting to overcome the higher gravity at earths surface, which is 9.78 meters per second per second down near the equator and drops in a non-linear fashion with distance,

Apparently you cannot comprehend the massive distances involved. At 20km, see above for why I use this, the acceleration due to gravity is 9.76. At sea level it is 9.82. Non-linear means jack shit when you start at 6371km and only go up a few dozen km. 0.7%, yeah bloody helpful.

and ploughing through the earths atmosphere, which generates drag and heat.

The amount of energy lost to drag is quite small, a quick calculation puts it at below 0.1% (of the thrust of the rocket) between 0km and 20km (velocity and atmospheric density cancel out more or less I think as you go up). Also at 20km, the highest you'll realistically get a plane to go, is still well within the atmosphere.

So you will need to send a rocket up anyway, specifically one that detaches from your lift vehicle. No spaceship can "pick up" your rocket because any such spaceship would no longer be even close to in orbit (to be at such low altitude/velocity). If you want me to explain the absurdity of it more then I will but hopefully I won't need to.

So let's look at the savings of launching at 20km instead of 0km altitude, the starting velocity in both cases will essentially be 0 (even 500km/hr is nothing).

The Soyuz launch vehicle, for example, drops it's first stage at 50km and has a velocity of ~2km/s or so I think. That stage is 30% of the whole things mass/fuel, the remaining mass is still ~120 TONS. Let's ignore the absurdity of trying to list 100+ TONS to 20km by airplane (needed for sizable payload), it's more than a 767 can lift which can't even go close to that high. Now you'd get a savings of maybe 10-15% of total at 20km once you take away those 0.5km/s of velocity it no longer has. The cost and complexity of dragging it that far up, by airplane, would more than counter any savings. Also even 20% savings is small as the cost is still absurd, a space elevator gives you maybe 95%+ savings over current rockets.

Which also causes the explosions that plague rockets.

And trying to ignite at high altitude, separate from a plane and so on will cause it's own problems. Modern rockets are decently safe.

Are you saying that the fuel you save utilizing conventional lift to reach the top of the atmosphere instead of using rockets is irrelevant?

Of course it is, fuel is amazingly cheap compared to all the other costs involved. The space shuttle for example is not absurdly expensive because of fuel but because of how complex it is to deal with (billions a year just to keep the launch facilities in working order). Your ideas are complex, compared to rockets, and so would incur massive costs of this sort.

It's so obvious that everyone in the private sector who is attempting to enter the arena of space flight has chosen this approach, including SpaceShipOne, which is functionally demonstrating the concept.

You picked the perfect example to discredit your own point. They could do it BECAUSE they didn't need to generate high velocities. They were orders of magnitude off from what any traditional rocket needs in terms of velo

Re:Why can't they be self powered?

[Fourier404]

Just scale everything up and stick a fusion reactor on the pod. I'm thinking about 1000 30 meter diameter "cables" and pods the size of small aircraft carriers.

Re:Why can't they be self powered?

[Rakishi]

I'd like to add that despite the insults in or tone of my post, which are simply my way of arguing online so don't take them too personally, I don't mean to discourage anyone from thinking creatively or considering new ideas. Nor am I dismissing all such ideas off hand simply because they are unconventional.

Rather I am arguing for considering such things in a rational and scientific manner instead of jumping up and down claiming to have found the equivalent of the alchemy or perpetual motion of yesterday. If you make ANY argument or claim you need to have sources to back it up. If at all possible those sources should be equations and calculations which you can derive and understand, anything less is not reliable. Don't accept something as true just because you heard someone say it in passing 5 years ago. That means you need to have a firm background in physics and the ability to understand those equations.

More importantly one needs to understand that there is a REASON things are done a certain way or a certain way is not popular. These reasons may be engineering or political but both are vital to understand. This means you need to understand the engineering process (of massive projects) in at least passing and that nothing exists in vacuum. Even a great idea may be practically inferior to a bad idea if the former can't be done efficiently in practice. In real life you have tons of complexities and costs beyond the raw math of the bare bones implementation of something.

The space elevator is for example simple in concept but absurdly complicated in implementation, things like effects of lightning alone probably require supercomputer based analysis. Practically speaking it is also too expensive to test till one works, due to both it's costs and relatively long life cycle. Rockets you can keep sending up till they stop exploding yet even those have absurd complexity compared to say a model rocket (at least one was lost asfaik due to vibrations induced from fuel in fuel lines or something).

In summary if you propose an idea you need to at least consider if it's viable from a physical, engineering, political, economic and probably other points of view. Not just part of the idea but a fully implemented version of it including any and all infrastructure needed for it. You may not understand even close to what the costs are in those areas but you need to at least understand why there could be large costs there.

Re:Why can't they be self powered?

[dbIII]

Except that the current design is many such relatively short tubes glued together

That will never work because the strength will drop an order of magnitude at least. What people are proposing is strands as long as twice the distance to geosynchronous orbit (counterweight) bundled together into a cable. As for the heating problem - remember that these things are extremely good conductors of heat as well as electricity and you are going to need a huge number of them to take the mass anyway - the fibres used to conduct electricity are going to be surrounded by a lot of fibres that can be used to conduct away the heat. The other option is to go for the full room temperature superconductor material that we also do not yet have but is potentially also not far off.

As the star wars project showed the losses involved in sending high intensity beams of energy about are astronomical so I don't understand why the MBAs and various enthusiasts that are pushing the crawlers don't propose powering it via one of the best conductors we know about - the carbon nanotubes they are proposing for the structure anyway.

Re:Why can't they be self powered?

[Rakishi]

That will never work because the strength will drop an order of magnitude at least. I believe the current approach is to use something like Van der Waals forces to glue the nanotubes together.

What people are proposing is strands as long as twice the distance to geosynchronous orbit (counterweight) bundled together into a cable. This is not practical, individual strands will break, corrode and so on which means that they will have to be replaced with shorter strands (or incur massive repair costs). More importantly we can't make tubes that long with any current (or near future) technology.

the fibres used to conduct electricity are going to be surrounded by a lot of fibres that can be used to conduct away the heat. Nanotubes are I believe not very heat conductive in that direction.

The other option is to go for the full room temperature superconductor material that we also do not yet have but is potentially also not far off. Those are considered by some theoretically impossible. Furthermore room temperature is NOT the temperature of a space elevator. Also such super conductors would add immense mass to the elevator.

As the star wars project showed the losses involved in sending high intensity beams of energy about are astronomical No it showed that hitting a half meter wide object moving at massive velocity with indecent (enough to melt metal) amount of energy is not possible. What is being discussed here is orders of magnitude easier and less energy intensive. If you're going to argue against something at least use bloody science not horrendously flawed analogies.

so I don't understand why the MBAs and various enthusiasts that are pushing the crawlers Interesting, so your method of argument is to try to discredit those who oppose your view? I mean we all know that no scientists or engineers work at NASA, why in fact we all know that they shoot any scientist who gets within 50 miles of their offices.

don't propose powering it via one of the best conductors we know about - the carbon nanotubes they are proposing for the structure anyway. Because they don't know what they will use, what margins they will have, what exact properties their particular design will have and so on. You need to get energy out of the conductor as well and physical contact is not a possibility which will induce losses. And thats just in regard to how small sections of the elevator behave, the overall ad interactions induced by such a large circuit are a whole different manner. They are working on the one method they CAN work on, they have too little information to consider any other methods realistically. As a result this is their current idea as it will work with any possible implementation.

Re:Why can't they be self powered?

[Rakishi]

I think it's driven by shady back room deals with the fuel industry, personally. Ah yes, those evil shady companies that create liquid hydrogen, liquid oxygen and aluminum (yup the last one is fuel used by nasa). They're such vile bastards. So ingenious to boot, having not only gotten NASA but having gotten their slimy hands on the soviet space program as well (less so, those damn kerosene and unpronounceable fuel companies beat them). During the heavy communist controlled days to boot. Not to mention the European, Indian, Chinese and god knows what other space programs.

Well okay, most actual rockets use kerosene or other more absurdly exotic fuels instead. Of course NASA doesn't actually have many such rockets and instead uses the shuttle which is LOX/H2.

Re:Why can't they be self powered?

[dbIII]

This is not practical, individual strands will break, corrode

Corrode? How? This is something effectively the same as sheets of graphite in the high strength direction which is going to be in contact with the same material in a vaccum. Also by breaking - by what mechanism? Wouldn't the design be such as to spread the load to somehting the fibres can take. I think you'll also find that the joining you describe is about bundling the fibres axially and not sticking bits on the end of individual fibres longitudinally otherwise you would lose an order of magnitude or two of strength.

Please explain the theory of high temperature superconductivity that shows it is not possible - all the theories I know are empirical and actually pretty confusing.

The MBAs I am talking about are the ones that are running the space elevator consortium which is not linked with NASA since NASA is doing other stuff. I assume they would like you to think they are linked to NASA. Personally I do not trust them so in places like above I state their highest qualification to point out the irrelevance of it. They should get their unnamed "consultants" to speak for them if they want a bit more credibility and that may happen some day, perhaps their consultants are real and just a bit shy.

Because they don't know what they will use, what margins they will have, what exact properties their particular design will have and so on

Strength of the carbon nanotubes is something we can't be certain of but ironically this is where bald certainty is expressed by the above mentioned space elevator consortium - but things like modulus of elasticity and conductivity are far more certain. If carbon nanotubes are going to be the answer we already know the conductivity - the same as you get across a sheet of graphite so actually very high conductivity.

Re:Why can't they be self powered?

[Anonymous Coward]

1) Yes, I am saying that. It's also true.
2) Yes, or rather no. I'm saying the fuel 'you save' does not exist.
3) Yes, +/- 1% at least.
4) Ha ha ha. I'm not the one throwing out Newton bud. Who sounds like an idiot?

The most fuel is not consumed at the surface of the earth. Modern rockets consume fuel, more or less, at a linear rate. Since modern rockets burn for more or less fifteen minutes, it's pretty damn clear most of the fuel is not consumed at the surface of the earth. Fuck knows where you get this idea. And I think you're confused about which part of a rocket's flight involves heating effects from atmospheric friction.

SpaceShipOne? Give me a fucking break. Tell me when they manage to park that fucker in orbit, and pay close attention to the massive fucking rocket they used to get it there and the airplane they might have used to drag the bitch up to 50,000ft if it weren't for the hugely oversized paylod.

And by the way, a spaceship that never has to 'bear its own weight' is a spaceship which never actually accelerates anywhere. Catch a fucking clue, dude. High School == good; TV == bad.

Don't even get me started on the Hulk.

Re:Why can't they be self powered?

[ShieldW0lf]

I would imagine that we could make use of electromagnetic acceleration of payload on quite a lot of cargo, but there would be more costs and inconvenience involved in packaging some cargo than others.

It wouldn't accelerate suddenly like a bullet because it's not being driven by detonation, but rather being accelerated as it moves out the barrel as it passes each electromagnet.

But raw minerals that are scarce in space, manufactured parts that rely on the presence of gravity to construct efficiently, these types of things would be ideal.

Re:Why can't they be self powered?

[khallow]

And? For it to be wrong, something has to be incorrect right? What was incorrect about my description? To aid your reply, let us note that the key benefit of White Knight was that SpaceShipOne launched from above most of the atmosphere. So the engines could be optimized better for near vacuum and the vehicle could experience less drag. In other words, White Knight played the role of a launch platform. Sure it also acted as a mediocre first stage and cut some delta-v (due to initial velocity and that extra height). There's no reason a launch platform can't perform other roles after all. Also, keep in mind that the rocket still had to provide most of the delta-v to orbit. So we're still launching rockets here.

The air-launched Pegasus illustrates this more clearly. There the benefits of launching above most of the atmosphere outweigh the benefits of the carrier aircraft as a first stage. Plus, the Pegasus has much better launch windows than a ground launched version would have since air-launch is almost independent of weather and one starts at an airport (and can manuever hundreds of miles after that) rather than at a fixed launch pad.

Re:Why can't they be self powered?

[khallow]

correct me if i'm wrong here but spaceship one didn't make it into space at all?

Space is officially defined as 100 km up. SpaceShipOne achieved that altitude three times.

also, your space pier idea... what kind of cargo are you expecting to survive the same g's a bullet experiences?

As I dimly recall, Project HARP launched payloads with electronics and from Wikipedia they mention several rocket designs that were proposed. Bulk cargo like water/ice, cryogenic fluids, etc would have no trouble with the acceleration.

Re:Why can't they be self powered?

[khallow]

One thing to keep in mind is that rockets work now under current economic conditions. There's no point to spending tens of billions of dollars to get the capability to launch a few hundred tons to orbit each year. My take is that rockets will bridge the gap between today's current expensive, low volume space launch industry and the far larger and more active market of the future that can sustain these other approaches.

I also see rockets playing a role in niche applications like emergency propulsion or in low tech systems.

Re:Why can't they be self powered?

[khallow]

Rockets are the most brain dead way to send things into space, it ought to be illegal.

The obvious rebuttal is that rockets work and are feasible in today's high cost, low volume space economy. As i see it, once companies like SpaceX start selling cheap, high launch frequency rockets, we'll finally see just what you can do with rockets and create the markets that will justify the less "brain dead" approaches to space access.

Re:Why can't they be self powered?

[qwerty shrdlu]

Solar power works fine for freight- just climb all day and park at night. After all, what's time to a robot?

Re:Why can't they be self powered?

[Rakishi]

Corrode? How?

Atmospheric effects (oxygen I assume among other things), random effects, micro-meteorites and so on. And of course the climber has to do just that CLIMB the thing, that constant contact will likely cause damage over long periods of time.

This is something effectively the same as sheets of graphite in the high strength direction which is going to be in contact with the same material in a vaccum. Also by breaking - by what mechanism? Wouldn't the design be such as to spread the load to somehting the fibres can take.

Nothing is perfect or indestructible.

I think you'll also find that the joining you describe is about bundling the fibres axially and not sticking bits on the end of individual fibres longitudinally otherwise you would lose an order of magnitude or two of strength.

No right now it's about using short fibers as we have no foreseeable technology to make massively long fibers. Pretty much short of specialized advanced nanomachines there is no sane way to make something that long, random problems will crop up and cause breaks or problems in every fiber before it gets even close to that long. The original designs involved using actual epoxy and apparently calculation still gave the result enough strength. Also current design have a tapering cable that is much thinner at the bottom than the top.

Please explain the theory of high temperature superconductivity that shows it is not possible - all the theories I know are empirical and actually pretty confusing.

As I said some theories, in other words someone claims it is not possible. Given current problems and the complexities of the best superconductors it may be the truth.

he MBAs I am talking about are the ones that are running the space elevator consortium which is not linked with NASA since NASA is doing other stuff.

The current power beaming competition is being funded by NASA, partially at least. There are a number of scientists/engineers in the group although the group isn't there to do research. Some of the research done for this can be found here:
http://www.spaceelevator.com/docs/

I really have no idea why people for some inane reason always claim others, despite being more qualified, are wrong while they, and their pet theories, are right WITHOUT even looking up the explanation for something. If you disagree with them you could have emailed them for justification, could have looked at the literature in the area, could have contacted people involved in the project and probably other bloody things. Let me be blunt, you're an atrocious debater, if you wish to claim that something is wrong then you need to do it in a LOGICAL fashion. That means you find out why something is done a certain way then rip it apart. If you don't know why someone is doing something one way how in god's name can you claim their reasoning is wrong? Instead you take up others time on slashdot, a place where pretty much no one is even close to qualified to discuss this subject.

The space elevator is amazingly thin first of all, millimeter thin at the bottom possibly and only meters wide. It is absurdly long, 35000km, and all energy need to be provided ground side for now. Each climber may require say 500watts of power for a 12day ascent which means you need to be supplying say 10MW to all the climbers at any given time (this is the energy they need to receive after all loses are taken into account, you need to send much much more). Carbon nanotubes aren't that amazingly conductive, an order of magnitude close to copper over long distances I believe. Graphite is for example a few orders worse than copper in that department I think. My quick calculation put the energy loss at over 50% easily (as in even when I'm being conservative) and I'd say it's way over 90% even in the mid point if you were to properly calculate it (with realistic values and considerations).

Re:Why can't they be self powered?

[Rakishi]

Even at top of the highest mountain in the world the air density is such that the drag from having something go 15km/s (ie: roughly what you need to reach orbit I think) would melt it. The resulting drag induced deceleration would also kill anything living inside it probably. It's possibly useful as a first stage mechanism.

Re:Why can't they be self powered?

[Hucko]

Nano-seconds? Decisions like these require careful contemplation "for a very long time..."

Re:Why can't they be self powered?

[dbIII]

No right now it's about using short fibers as we have no foreseeable technology to make massively long fibers.

In which case the entire game is off for beanstalks until you can. The requirement is strength in the Gigapascals and you lose that at joins. I suggest you look at it in a bit more detail and consider the ramifications of something that is only millimetres thick at the base.

For graphite I was talking about the high conductivity and high strength direction as you would see along the length of a carbon nanotube and not the bulk properties - the reason nanotubes are so interesting is becuase you can line it all up and get good properties.

It's not really a debate since we have little in the way of terminology in common as seen by the corrosion question and the reply - I'm just making some statements of an opinion and make of them what you will. I would actually prefer if we went completely off topic and you said a bit more about the superconductor problem because that sounds a lot more interesting than playing "whatif" with non-existant materials from different directions and me wondering if there is claim salting or Lysenkoism involved in liftport or real science.

conductivity of space elevator cables

[jms]

Question -- how is the conductivity of space elevator cable? Could you have the cable consist of two electrically insulated cables held together somehow, then supply electricity across them?

Re:conductivity of space elevator cables

[Rogerborg]

Given that the materials required to make them are completely conjectural, you can imagine any conductivity you like. From all the sparkling, I think that fairy wings must be pretty conductive, so let's make space elevators out of them.

Re:conductivity of space elevator cables

[pushing-robot]

Or just one cable, taking advantage of the fact that it runs all the way from the ground to the magnetosphere.

But designing a lifter now when we have no way of building the tether itself is like constructing a "Moone Carriage" in H.G. Wells's era. Once materials science reaches the point that we can build reliable hundred-thousand-kilometer nanotube (or another equivalently strong and light material) cables, we'll probably be able to build far better lifter than we can now. And we'll know the characteristics of the cable we're building it for, which won't hurt.

Don't we need a tether first?

[flyingfsck]

If one can make a strong enough tether, then the obvious solution would be to leave the big heavy motors on the ground and run the tether around space based pulley, but I guess that is too simple to get funding. KISS just doesn't cut it to secure government money...

Re:Don't we need a tether first?

[Anonymous Coward]

Yes, but the engineering challenges of making a cable at least twice as long...

Re:Don't we need a tether first?

[pushing-robot]

The concepts for tethers usually involve them being thicker in the middle than at the ends, so as to reduce weight in areas that have less load (and don't need as much strength). A looping cable would make that impossible. What might work is a pair of cables that oscillate vertically, out of phase with each other, with a lifter that "walks" up or down by switching between cables as they change direction.

But whether that is more or less feasible than beaming power to the lifter, or collecting power from a conductive cable, is entirely dependent on the tether material, and the tether is a far more formidable engineering challenge. It's silly to design the lifter until we have a design for - or even a means of constructing - the tether itself.

Re:Don't we need a tether first?

[Captain DaFt]

I dunno, seems sillier to me to put up the cable, then sit around for years while somebody figures out how to use it.
This way, once the cable is raised, we should have lifters that are tested and ready. (At least in theory.)

Re:Don't we need a tether first?

[rbanffy]

"It's silly to design the lifter until we have a design for - or even a means of constructing - the tether itself."

I fully agree. This is a huge waste of time, talent and money. Until there can be a tether - and there is none in sight - it's a bit premature to develop the climber.

It would be a whole lot more clever to invest in simpler, dumber, cheaper rockets that don't need LH2 for fuel (as the 1st stage of the Saturn V didn't) for now, to invest in nuclear-thermal rockets for the next-generation and maybe invest in some kind of automated facilities that could manufacture stuff on the Moon, where the launch costs could be minimal compared to our gravity well (assuming we could get the raw materials required, which is not a trivial question). Even if Moon-based manufacturing could only deliver the simplest components (structural tubing, simple metal sheets, cables) anything you don't have to launch from Earth is great news.

For #1 I suggest getting back to basics. People already did a Saturn V running on kerosene. It cannot be too hard to do it again. For #2 there has been a lot of development and I like the nuclear light bulb approach and for #3 someone could start by sending a dozen rovers (not trivial because they must do a powered descent that most landers didn't have to do for the past decades) and let them be dumb and remote controlled from Earth (the Moon is about a light-second away) but with some interesting soil sample analysis equipment.

It seems NASA is frequently caught in a situation where they appear to be enjoying developing the most complicated solution to a given problem. I can't blame them, as I also get caught enjoying work too much every so often, but, come on... Sometimes it gets ridiculous.

Re:Don't we need a tether first?

[tkw954]

The concepts for tethers usually involve them being thicker in the middle than at the ends

Like a brontosaurus.

Re:Don't we need a tether first?

[Peeteriz]

Actually, don't most of the designs require the climber as the MEANS of building most of the tether?
As in, get a single (low weight, low capacity) strand up via rockets, and then have climbers pull up the 1000 other strands in order to get a tether strong enough for full-sized cargo.

So climber is a pre-requisite for building the elevator, not something that comes after it.

We still need a viable material for the tether, of course - but that's a different problem in a rather different area of science and that is being worked on in parallel with this issue.

Re:Don't we need a tether first?

[White Yeti]

I'm trying to picture the "vertically oscillating cables." How about a rotating-tether skyhook?

Is there a reason for such a competition?

[Jartan]

From what I understood even carbon nanotubes are not going to cut it without some major breakthroughs.

For something we still aren't really capable of achieving I would think something like the X-prize that gives rewards for necessary breakthroughs would be more logical than a competition which people will keep failing to win every year?

Re:Is there a reason for such a competition?

[Dunbal]

While I agree that the concept of space elevators is cool, perhaps NASA could concentrate on making parachutes that deploy when they're supposed to...

I don't get it...

[E 99]

What's the point of doing the whole laser-powered thing? If it's possible to have a ribbon to space, it should be just as possible to have a closed loop of ribbon to space, with a motor that drives it at either the top or the bottom, no? They could even engineer it like the common cable cars that take people to the tops of mountains. Imagine how stupid it would be for them to engineer one of those cable car systems with the car being self-driven.

Re:I don't get it...

[Anonymous Coward]

Now imagine how well this works out if the cable running around such pulleys is made of a really stiff material that's not all that bendable and prone to separation/fraying. Do you still want to go for a ride to the top?

Re:I don't get it...

[khendron]

A moving cable driving by motors would not scale very well. Imagine the momentum of a cable moving in a 22,000 mile long loop. The energy required to get it moving would be tremendous, and the problem of stopping it again would be immense.

Re:I don't get it...

[E 99]

I can't find any actual estimates of the linear mass of the various theoretical materials to be used. But if the momentum is really too great for starting and stopping, it could just be kept rotating indefinitely, and loads going up or down could just clip onto or off of the appropriate side at the beginning and end of the journey.

Re:I don't get it...

[khendron]

Neat idea. But then if the cable did stop, or try to stop, due to mechanical failure the results would be catastrophic. Having the cars motor themselves way up the cable keeps failures localized.

Re:I don't get it...

[afxgrin]

It's so the military gets their toys man.

Who doesn't want giant fucking laser beams?

Maglev rockets?

[Loke the Dog]

I think maglev-accelerated rockets has more potential than the space elevator. Whatever happened to that research at NASA?

I'd like to see a competition to shoot a sensitive cargo (an egg perhaps?) the furthest distance using some kind of maglev catapult without the cargo breaking. Casing of any kind, wings and a parachute are allowed.

Unlike a space elevator which either works or doesn't, this stuff has potential even if never gets anyone into space. Trains obviously, aircraft, weapons or even quick delivery systems could build on this technology.

Re:Maglev rockets?

[DerekLyons]

I think maglev-accelerated rockets has more potential than the space elevator. Whatever happened to that research at NASA?

Somebody finally did the math and figured out that the scheme really doesn't work (for space launches). More weight is required in structural reinforcement than is saved in unneeded fuel.

Re:Help!

[Rod Beauvex]

Damn, why is it my mod points are always gone when I actually want to use them...

I spewed my drink all over my monitor. You made my day.

Saskatchewan

[epp_b]

What? You mean things actually do happen in Saskatchewan?

- a Manitoban

Re:Saskatchewan

[Bushido Hacks]

"Whoot are you tooking aboot?" --some Newfie.

Re:Saskatchewan

[Jerry Rivers]

They sure do. Saskatchewan is where hey count the planes that fly over Manitoba.

counterweight

[lobiusmoop]

Just a thought - in regular elevators, the work required by the motor is minimized using a counterweight, so that the motor, rather than having to lift the full weight of the cabin, instead is just moving an (almost) balanced cable - the cabin at one end, the counterweight at the other.
  Obviously you couldn't do a similar setup with a space elevator since gravity at the top is much differennt from at the bottom, but if you had many (hundreds/thousands) of short counterbalanced cabins set along the length of the cable with automated transfers between cabins, would that make a workable system requiring much less energy to climb to the top?

Re:counterweight

[MrKaos]

Maybe that's the reason to have beamable power, cars on the downward run could recover energy and transmit it to either other cars or a collecting station.

Like an electric counterweight.

Use an energized tether line

[foniksonik]

There are a lot of comments about the method of energizing the lifter-robots... why not energize the tether itself, run current through it and let the lifter use Electromagnetic Induction and a capacitor as a battery to leach energy off as it goes?

Is this not feasible for some reason?

Since when did elevators crawl?

[bbn]

They should simply build this thing like a normal elevator with a counter weight going down while the payload goes up...

Re:Since when did elevators crawl?

[Quiet_Desperation]

They should simply build this thing like a normal elevator with a counter weight...

Or another elevator.

Why not build the Wonkavator?

[Bushido Hacks]

Surely, we would have to buy the rights from the Nestle Corporation, or the estate of Ronald Dahl, but why settle for a "space elevator"? An elevator can only go up and down, but the Wonkavator can go sideways and slantways and longways and backways and squareways and front ways and any other ways that you can think of.

Re:Help!

[Anonymous Coward]

Nah, that tastes like crap.

Re:Help!

[nilbud]

Tell her brother, that should clear things up.

USST video is last year's; this is the THIRD year

[seanthenerd]

Just a few corrections to the article:
The youtube link is to the U of S's winning round last year; it's now the third annual space elevator competition. The rest of the article is correct. It's worth noting that the height and speed requirements are double what they were last year.

Hopefully the weather will be better tomorrow and the competitions will continue! All the best to all the teams... and especially the USST, of course. :-)

Question

[bxwatso]

I have looked into this, but I have never found an answer.

Wouldn't the downward force applied to the system from an ascending load cause the ribbon to lag behind its earth anchor? It seems that some kind of propellant would have to be hoisted into space and then used to keep the free floating space modulule at the top from lagging behind and eventually falling out of orbit.

Conduction

[cidz0r]

On the concept of sending power through the wire, keep in mind that this cable is going to be tens of thousands of miles long. Even with a very high voltage, and low resistance medium, we are still talking about a *lot* of resisitance.

Re:Conduction

[Jerry Rivers]

Maybe it would be possible to self-generate power as it moves up the wire?

nanotubes can have very good conductivity

[j1m 5n0w]

According to wikipedia, depending on configuration, carbon nanotubes can be quite conductive. I don't know if this makes supplying power from the ground practical or not, nor if one can make a nanotube that is both sufficiently strong and superconductive. A cable that can carry a couple megawatts of power per lifter with low loss may need to be much heavier per unit of length than the elevator would otherwise be.

Re:nanotubes can have very good conductivity

[j1m 5n0w]

There's a good answer to this question here.

sending mass away?

[fishbowl]

Has anyone considered the effect of reducing the mass of the planet by sending matter to (or past) orbit? Call it insignificant if you want, but once it becomes cheap and easy, we will not only pollute space, but we will also reduce the mass of the planet.

Re:sending mass away?

[Jerry Rivers]

Isn't the mass of the planet constantly increasing because it's being bombarded with meteorites?

Re:sending mass away?

[fishbowl]

So maybe our survival *depends* on sending stuff into space...

Re:sending mass away?

[Anonymous Coward]

Innumeracy is sad, isn't it? Won't you help?

For less than 6 x 10^27 pennies per day, you too can help someone learn to do arithmetic.

Migod, are they bored or what?

[aqk]

I know Saskatoon is a rather boring town, bu do they have to resort to this kind of crap?

Somehow, I suspect my Canadian tax dollars are paying for much of this pseudo-science.

Why don't they establish a science chair to examine the possibility of extracting sunbeams from cucumbers?
I'd be willing to donate some pinoqachole chit for this more worthwhile project!

Re:Migod, are they bored or what?

[Jerry Rivers]

Relax. If they win the prize it probably won't cost you a dime. Though i must point out that people called the Wright bros. crazy. Others said going to the moon was impossible. At one time, people actually believed that if you travelled at more than fifteen or twenty miles an hour it would kill you. So maybe what you think is a waste of time and money will actually turn out to be the invention of the century. We'll never know if nobody tries to do it. And aren't Univerities supposed to encourage learning through research and development?

Re:Migod, are they bored or what?

[afxgrin]

pfft - the only thing your tax money is going into is the student debt the team members are gathering while in school.

There's a rule that you can't have government funding for this competition either.

The team I'm on - www.punkworks.ca - is privately funded by the team members, and I'm not one of the people shelling out the cash for this. We're not listed as one of the competing teams, but we started working with McGill University, and they got in an accident on the drive down there .... so last I heard from the guys in Salt Lake City is that our microwave generator cabinet isn't working anymore, and so we'll yet again not be able to showcase what we've been working on almost every weekend for the past two years.

--Nick B

Niac funded analysis...

[MrKaos]

...was conducted by Dr Bradley C. Edwards. Since I read the study it's been put into a summary.

Can't find a link to the original study atm, which has more detail.

Actually,the DOD is currently funding this.

[WindBourne]

They have changed the layout from a long track, to being a circular track in a vacuum, and then slowly speed the system up. The issue was changed from one of costs (never about energy) to one of Gs. In fact, it was shown that the energy on this is MUCH better than rockets.

Assume that you do the straight track, than you need one that is 100's of miles long, which leaves it vulnerable to attacks esp. when you need it most. And the worse attack of all is congress.

With a much smaller circular track, it takes a while to get the speed up, but the costs are significantly less. The problem here is that this is not suitable for humans. But then again, the DOD is not interested in sending up humans on these. Instead, it will be used to send up 1000KG of goods that can withstand the prolonged Gs. That may sound like very little, but the DOD can then launch small spy sats as well as send up packages of food, fuel, water, construction equipment, etc.

Incorrect on a Number of Points

[el_munkie]

There's no clearly defined border one can "nudge" a payload across. There is a minimum velocity one must hit, and the velocity added by the plane and the fuel savings from the reduced high-altitude would be negligible.

One bit of stupidity stands out:
For such a smart bunch of people, NASA sure have been taking a stupid, dangerous and wasteful approach to space travel all these decades. I think it's driven by shady back room deals with the fuel industry, personally.

You do realize that most rockets are powered by hydrogen peroxide and oxygen, right?

Re:Maglev rockets? (or:no railgun on Earth)

[Anonymous Coward]

Terran (Earth)-based rail gun will not work. Simple reason.

MINIMUM orbital velocity is in the range of Mach 25. The 'sonic boom' of an aircraft at 30,000ft going Mach2 is enough to start breaking windows. Now figure the fact that you are going to lose a lot of speed on the way up due to drag. You will need a 'muzzle velocity' of greater than Mach 30. Keep in mind Mach 6 is enough to cause tremors in the crust strong enough for sesmic stations to pick up. What do you think Mach30 is going to do? Even if you built it on the top of Everest, it would just not work.

On the moon, on the other hand, it would be a superb launch vehicle.

A Moon Space Elevator is a better first step

[watermodem]

The tech is mostly there to build a space elevator to lift things from the Moon's surface to orbit.

That is a much better and more useful first step.

2m/s

[Colin Smith]

35,000,000 metres ...

... such a painful subject

[Anonymous Coward]

"... and while you're at it, why doncha give me a paper-cut and pour lemon juice over it. We're closed!"