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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."
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.
I am one of many. My idea is not unique, nor do I expect my voice alone to sway you. I speak in a chorus of opinion.
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.
"" How about taking the safety labels off everything, and let the stupidity-problem solve itself? """
Given the mass ratio between anything we can send up and the average icy space rock, it's more likely the icy asteroid's gravity will capture the craft than the other way around. Not that it's a bad thing, mind you.
Pathman, Free (as in GPL) 3D Pac Man
Honestly, have we learnt nothing from Jerry Bruckheimer's excellent film Armageddon.
Refuelling in orbit is dangerous!
Next they'll be suggesting we man these orbital filling stations with drunken Russians. I only hope Ben and Bruce are there to sort things out when matters go awry.
Space One proved that a competition with a good incentive can produce results faster than state sponsored research. I hope the trend will continue.
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.
When I worked at Boeing, I was in charge of a fuel-depot study.
The method we looked at was a BFG to launch the fuel into orbit.
The big gun used hydrogen gas that is quickly heated in a heat
exchanger, then pushes a 600 kg projectile to 2/3 of orbital
speed. The projectile uses some onboard fuel to go the rest
of the way to orbit, then delivers the remaining 100 kg of fuel
to the orbital gas station. The projectile de-orbits and is
recovered to be reused. The projectile is rugged enough that
it can land on anything without damage.
The big gun is very cheap ($100M) compared to electromagnetic
launchers, because it is basically a length of pipe, compared
to a series of coils, switches, and big power supplies. On the
other hand, it is more expensive to operate.
The velocity split between the gun and the projectile depends
on the size of the projectile and how much traffic there is to
orbit. For the case we were studying, delivering fuel to
carry comsats to GEO, we were launching 100 kg a day, or 30 tons/yr
(allowing for downtime).
DRN
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" 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.
By and large, a change in mass shouldn't affect an orbit - speed and altitude (orbital radius) are interdependent. It would affect drag (atmospheric & from the 'solar wind' - less mass = less momentum so drag would slow it down faster), but that's about all.
"It's time to take life by the cans." ~ Bender ("Bendin' in the Wind", ep. 3-13)
Assume it is water to be split. First it has easy requirements for storage. Compared to h2 and o2, it is positively trivial to store and work with (in liquid and solid form). 2'nd, this does not need to be shot up there. It could also be shot up an electronic railgun, or a maglev, to get the initial acceleration. It should be possible to get it going into top subsonic and then allow a much smaller rocket to take it up. Nice advantage of this, is that it could be used on a continutal basis for other cargo that is relatively inert to high Gs.
I prefer the "u" in honour as it seems to be missing these days.
Actually, the article summary is a little misleading.
NASA's role has always been vision, specification, oversight, and operations. Design and construction have always been contracted out to the public sector, and to the universities.
Classic examples of this method are the Gemini and Apollo projects. NASA's document, Chariots for Apollo gives a fascinating account of how this process works.
Any sufficiently well-organized community is indistinguishable from Government.
No, hydrogen is explosive. I'm not sure what neat trick you saw, but I would guess it was likely a decrease in pressure after an explosion caused by two gases combining to become a much denser liquid. In other words the container (attached to a balloon?) contained the explosion and then the water vapor condensed lowering the overall pressure.
Anyway, one of the reasons why to use hydrogen is that the hydrogen/oxygen reaction has an extremely high specific impulse for a chemical rocket. Here is a Wikipedia link that explains more, but basically it is generally one of the most efficient chemical rocket fuels available.
Also, of course, it (water) is super cheap, abundant and safe to lift.