On Orbital Fuel Stations

dylanduck writes "Being able to fill up your spacecraft from a fuel depot in orbit round the Earth or Moon is key to the long-term prospects of astronauts exploring the solar system, according to NASA engineers. Trouble is NASA doesn't want to build it themselves. So there's $5 million for any enterprising groups who can develop a simple version themselves."

It's doable

[PatrickThomson]

Obviously you need atoms up there, which have to come from somewhere, but splitting them into fuel is easy, you're floating in space with all this sunlight. The problem is that if you carry a kilo of water from the surface and then swap it for a kilo of hydrogen/oxygen when you get to space, the benefits are minimal (easier storage?). This would work well coupled with a captured icy asteroid, even a small one.

Hmmm

[hyfe]

Erm, you still have to get the fuel up there right? .. and the cost of putting something up there is still reasonably proportional to weight?

So sure, once you get liquid hydrogen from the moon / some other energy source it'd be usefull.. which pretty much means we need a moonbase first.

I, for one, welcome our oxygen yielding overlords!

[holdenholden]

I say good for NASA. They are finally starting to realize that science can be done outside the government laboratories too. An (academic-type) researcher wastes plenty of time begging for money, writing grants and often balancing a teaching load. In industry, on the other hand, you worry less about budgets and more about what you are trying to achieve and how to achieve it. There is a flip side as well--in academia you are free to work on pretty much anything you like, while in industry you work on whatever your manager wants you to work. In the happy case when your interests and the company's interests coincide, you are only limited by your skills and your knowledge.

Space One proved that a competition with a good incentive can produce results faster than state sponsored research. I hope the trend will continue.

Zero Gee problems?

[Cicero382]

Has anyone else noticed that zero G is a constant PITA for nearly all space applications?

A short list includes:

Human health (bones, muscles, fluid accumulation etc)
Environment (air flow, hygeine)
Fluids in general (measuring, pumping)
Going to the toilet (or john)

And lots of others.

I have a question: Why aren't we putting some effort into artificial gravity? I mean centrifuge effects - not Star Trek. After all, we're expending all this effort into individual engineering solutions for each problem. If we had AG of some sort, wouldn't that remove the need for that?

Just my 2 pennies worth.

Re:Hmmm

[MichaelSmith]

Erm, you still have to get the fuel up there right? .. and the cost of putting something up there is still reasonably proportional to weight?

Fuel depots make sense for aircraft on Earth because you can use cheap surface transport to deliver the fuel, store it, and then load it into your aircraft when needed.

This might work in space if you have ion powered slow boats to ship the heavy stuff, and fast human carrying vehicles to load up on fuel. But we are not that advanced yet. If we go to mars any time soon it might make sense to launch the cruise stage unmanned and then hook it to the command module in earth orbit. That would be a kind of fuel dump.

Re:Hmmm

[cnettel]

I somehow imagine that the pylon construction could be far more expensive than the power plant part.

Re:Hmmm

[adam1234]

Most of NASA's budget inevitably goes to people (ie, payroll) and bureaucratic oversight, not operations.

Re:Zero Gee problems?

[GroeFaZ]

Obviously, the cost-benefit-analysis, at the current state of technology, does not speak in favor of simulated gravity or the engineers would've done it already. Rocket engineers must justify every pound of mass they want to put into space (which is, by the way, an argument against manned space flight), and, while needless to say, it's just a LOT easier and cheaper to let an astronaut pee into a plastic bag and toss it out the window than designing the rocket with 2 huge rotating discs tens of meters in diameter. Ditto for all other points you mentioned.

If and when our technology has matured enough so we can start designing RAMA-style spaceships [wikipedia.org] or large spacestations with permanent crews of dozens or hundreds, then this or another kind of AG will certainly be included.

chemical reaction propulsion

[zogger]

I doubt there will ever be a cheap/easy/affordable way to do this with chemical reaction rockets. If there was it would have been thunked up by now, doncha think? What you see is what ya get, big ole rockets carrying a relatively small amount of stuff up at great cost.

  We won't become much of a space faring race until we have *advanced physics drives of some sort that work with gravitrons or something along those lines.

*note:said "advanced". We need to be able to understand and manipulate gravity in some fashion, right now the best we can do is we sort of measure it AFAIK.

One chemical alternative: wildcard long shot: could we build rockets where the structure (parts of it anyway) of the rocket itself could be transferred to being fuel? A cannibalizing rocket in other words, save a lot of weight that way and get more fuel to orbit.

    This idea is a variation on the "caseless ammo" [wikipedia.org] concept. I saw one of these rifles before that used this sort of ammo, made by Daisy the BB gun guys, it worked perfectly fine, no brass at all. The concept never caught on much, but it worked. So maybe there is a way there to get a lot more fuel into orbit for much less cost than currently. Don't ask me for a detailed chemical composition outline though, no idea, just the concept of cannibalizing rockets.

Re:Zero Gee problems?

[smilindog2000]

It's not as bad as people think. You need a long cable, with a good tensile strength to weight ratio. A simple steel cable will do. On one end you attach the space station, which could be as small as a single module of the current space station. The other end needs a weight, supplies, another half of the space station, space junk... whatever. Then you spin the thing. No big deal.

To dock, you pull up to the middle and grab old of the rotating cable. You then lower yourself down to the station, and enter through a hatch on 'top'.

I think for long-term living in space, it's a win. For the short term, it adds complexity and cost that nobody wants to pay for.

It's not rocket science :-D