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NASA Tests New Moon Engine
Posted by
Soulskill
on Sat Feb 21, 2009 11:20 AM
from the rocket-fuel-green-cheese-hybrid dept.
from the rocket-fuel-green-cheese-hybrid dept.
Iddo Genuth writes "Pratt & Whitney Rocketdyne of West Palm Beach, Florida has successfully completed the third round of its Common Extensible Cryogenic Engine (CECE) testing for the National Aeronautics and Space Administration (NASA). CECE is a new deep throttling engine designed to reduce thrust and allow a spacecraft to land gently on the moon, Mars, or some other non-terrestrial surface."
NASA is also set to launch a new satellite on Tuesday — the Orbital Carbon Observatory — that will monitor the level of carbon dioxide in the atmosphere. On the research front, NASA has announced this year's Centennial Challenges. $2 million in prizes are available for a major breakthrough in tether strength (one of the major obstacles for developing a space elevator), and another $2 million is being offered to competitors who are able to beam power to a device climbing a cable at a height of up to one kilometer.
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NASA's Orbiting Carbon Observatory Set For Launch Tomorrow 183 comments
bughunter writes "The Orbiting Carbon Observatory (OCO) is slated for launch tomorrow, February 24, 2009. OCO is the first earth science observatory that will create a detailed map of atmospheric carbon dioxide sources and sinks around the globe. And not a moment too soon. Popular Mechanics has a concise article on the science that this mission will perform, and how it fits in with the existing 'A-train' of polar-orbiting earth observatories. JPL's page goes into more detail. And NASA's OCO Launch Blog will have continuous updates as liftoff approaches and the spacecraft reports in and checks out from 700km up."
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Space elevator power? (Score:5, Insightful)
Wouldn't it just make more sense to have solar panels in orbit and transmit the power along the space elevator? If I remember correctly, this is what Kim Stanley Robinson envisioned with the space elevator in his science fiction novel Red Mars [amazon.com] . Being able to bring power down would be a nice bonus for a tool to get up to orbit easily.
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It's the same problem whether you are sending the power for the climber up from below or down from above.
Nuclear Batteries (Score:2)
I have always wondered why we can't have something like a nuclear battery on board the elevator. Is it their weight/volume that make them impractical?
Recent articles like this one http://www.sciencedaily.com/releases/2005/05/050514205902.htm [sciencedaily.com] suggest such technology is in development. And they nuclear subs already have their own power supply.
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i would guess that the power output is too small to overcome gravity
nuclear batteries on probes have a very small output, barely enough for the onboard electronics.
Nuclear subs on the other hand are immense and heavy.
And nuclear subs have a much better temperature gradient to work with, since they have an infinite supply of water for cooling.
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I think you're confusing a radioisotope battery with a nuclear reactor.
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No, he's not, he's bringing-up both types in the same reply.
He casts-off RTGs immediately because their power output sucks, and then he dismisses naval fission reactors [fas.org] because (1) they're huge and (2) you need a way to remove the waste heat.
Unfortunately, efficiently creating mechanical/electrical energy from heat requires a large temperature differential. Once you've used-up all the energy you can and the temperature drops, the remaining energy is waste heat, and must be removed from the system. Naval r
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Carbon nanotubes are,
Granted.
and naval reactors are, like, the size of a dustbin.
Did you even READ the link I posted? The smallest reactor core on that page has a volume over 32,000 cubic feet, and weighs 1130 tons. 1130 TONS. That's one gigantic dustbin.
And keep in mind, these are some of the world's most advanced reactor designs. While the civilian nuclear power industry has largely langushed in the last 30 years, the military has been running a tight ship. You really can't make them any smaller with
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Wouldn't it just make more sense to have solar panels in orbit and transmit the power along the space elevator?
How do you know it makes more sense? How are we going to transmit the power along the tether? My point here is that we don't know enough to make such a determination.
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...was reading just the other day about this company that proposes to put up solar panels in orbit and beam the energy down via microwaves. Now there was an image of an antenna farm on the earth below, implying you need a large collector area for this to work. However, the energy could be tight-beamed via a maser to a small antenna, perhaps - a small, light antenna mounted on the climber.
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Wouldn't it make more sense to just not bother. For sheer impracticality, space elevator is one of the silliest ideas ever.
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Why? There are some problems to overcome, sure, but I don't see obvious show-stoppers.
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Apart from the really obvious one of needing an almost infinitely strong piece of cable? So far, carbon nanotubes (the main contender to make a very strong cable) are limited to being only a few millimeters long. Not quite the several kilometers they require for a space elevator.
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i call bs.
for sheer impracticality, chemical rockets are one of the silliest ideas ever. and look, they still managed to catch on.
Re:Space elevator power? (Score:4, Informative)
I think one of the silliest notions I ever heard is the idea that we could propel a carriage without a horse, by using explosions from a highly explosive liquid substance. Obviously the first time they try this they are just going to blow the carriage sky heigh. The simple reason this will never work is that they forgot that a carriage has a thing called inertia, and it will quickly buckle under the force of the explosions rather than be propelled down the lane. Even if it could withstand the force of the explosions, could you imagine what kind of jerky ride you would have?
Parent
ust not bother???? (Score:3, Insightful)
Why then try to do anything? Artificial light, nuclear power, cars, organ transplants? They were all impractical at first.
If this was a rhetorical question, then I lost and bit, but otherwise, with this attitude, not much would have ever been invented or tried.
The space elevator might be the best and most efficient way to get large amounts of material into space, unless we invent anti-gravity.
Re:just not bother???? (Score:2)
The space elevator is more than likely just a materials engineering problem, while anti-gravity would require spectacular new scientific theories.
So yes, but still I don't think much is impossible, much of what we take for granted now would have been impossible 500 years ago.
Re:Space elevator power? (Score:4, Insightful)
Parent
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Yes and no. Yes, by itself the moon's slow rotation would call for a really long tether (to match the 27.3 day rotational period, and the counterweight would be too strongly influenced by Earth's gravity. I haven't done the calculations, but it wouldn't surprise me if the tether would have to pass through the Earth itself.
However, there is another space elevator design that will work. Between the Earth and the Moon lies the first Lagrange poin
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Apparently we have sufficiently strong materials right now to be able to create such a tether. There are still engineering difficulties (such as getting a 56,000+ km length of kevlar rope strung out from the moon to the counterweight) but a lunar tether lies within our current technological capabilites
The problem is that we don't actually need a lunar tether until we have one attached to Earth.
I would think that at some relatively low altitude it becomes more efficient to beam the power down just because you don't have to go through so much atmosphere.
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No. You're probably thinking of a space fountain.
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would be cool if somehow a superconductor transmission line could be incorporated into the space elevator (weight issues a prob). Or have it conducted on the surface (didn't NASA look at power generation from a tethered cable?) of the elevator cable. I'm not a EE so please forgive any ignorance.
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Maybe. Build a space elevator and try it.
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Actually, it makes the most sense (to me) not to use a powered 'climber' at all.
If the space elevator is ever deployed, instead of dropping a single tether down to Earth, they should drop a LOOP. Run the bottom of the loop around a pulley on Earth, and the top through a pulley on the counterweight in space. Add a motor to the pulley on Earth and you've got one half constantly going up, and the other half constantly going down.
All a 'climber' would then have to do is clamp onto the cable and allow itself to
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My idea of a pulley was something about 50 to 100 meters in diameter, much like a ferris wheel. It had less to do with flexibility though, and more to do with reducing wear and tear on the 'tether loop', preferrably bending it through a large radius, and exposing it to a large surface area for traction to drive it.
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You missed:
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Wouldn't it just make more sense to have solar panels in orbit and transmit the power along the space elevator?
I imagine it might add too much weight or complexity. Even just running two strips of conductive tether separated by an insulator may be too much considering how feasible the tether is to begin with. Then there are things such as resistance to consider. Might simply be easier to beam it seperatly rather than add another layer of complexity to something that is already pushing the limits.
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If you attempted to stick a current through the elevator cable, my primitive understanding of physics says, oscillations will start to occur in the cable due to the way magnetism and electricity are related?
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The Earth's atmosphere doesn't reduce the intensity of sunlight that much that we need to put solar panels in orbit.
Solar power stations in orbit don't require as many resources as the same stations on the ground (very large mirrors can be thin and light in microgravity, etc) and produce their full power output nearly 100% of the time, tracking the sun 24/7 and only rarely going into the Earth's shadow. They also don't take up a huge amount of space on the ground which could be used for other things, like growing crops.
That's not to say that they would be cost-effective, but there are good reasons for preferring space-ba
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Sounds good, though you have this problem of the original elevator is (currently well outside) at the limits of material strength over such a long distance --- AFAIK the weight to strength ratio limits the size of our current buildings to only a little larger than the Kuala Lumpur building as compared to the distance to build an effective space elevator. Our buildings do rely on compressive strength rather than tension that a space elevator type buildings would use.
If you were to then have a cable with in a
A what? (Score:2, Funny)
Took me a second look to realize that I'd read it wrong the first time...
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It's a step toward the soixante-neuf drive used by the ship Hwang Ho in Philip Jose Farmer's (under the peudonym of Kilgore Trout) "Venus on the Half Shell". So named because it could achieve 69000 times the speed of light, obviously.
Of course they are testing. (Score:1)
I'm a huge elevator evangalist but... (Score:2)
This looks way better http://en.wikipedia.org/wiki/Space_fountain [wikipedia.org]
New? They had these in 1936! (Score:3, Informative)
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Actually, if you read the page - you'll note that rocket engines are specified, not jet engines.
Orbital Carbon Observatory Isn't (Score:2, Troll)
The Orbital Carbon Observatory doesn't measure carbon dioxide, it measures spectral absorption of sunlight reflecting off the surface of the earth.
The really cool thing about this is that the analysis is so sensitive to factors and assumptions that the results can be anything we want them to be.
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Hmm...Ok some thoughts....
We have worked on star wars programs....Is it not possible to build a super precise Laser based weapon to target the terrorists no matter where they are? A small pulse of Laser in the head of terrorist and he is gone. A good telescope with good precision laser should be able to take care of any terrorist without launching any drone attacks. I understand it may have its own technical challenges, but US certainly can do it. Isn't it?
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My question is, though, how do you stay off the terrorist/person of interest/'enemy combatant'/etc list and still have some reasonable freedoms left? And how thick will the tinfoil need to be to keep that 15 MW laser from toasting your brains?
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And no, geostationary is too far out of sniping.
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