Slashdot Mirror
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
Does that incur the costs of it failing?
ilovegeorgebush
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.
Put a really powerful pump into (geostationary) orbit connected to a really long straw into an ocean.
Now, that is interesting!
In fact, that makes me wonder, how do they measure basic attributes like weight, volume, speed over there in space.
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
So the question remains, How much money will you recieve if you can install linux on them?
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.
As long as we can spawn the human race onto other planets, just incase our planet become inhabitable. It will all be worth it.
A bit of planet redudency wouldn be nice.
Sort of like a raid5 for the human gene pool.
Well, maybe not. But I have to wonder, why not just store the water, instead of separating it and storing liquid oxygen and hydrogen? You've got plenty of energy available up there from sunlight, so you should be able to split the stuff when it's needed, thus avoiding the problems of storing the liquid gases long term.
So my winning design is a huge ice bucket attached to a big set of solar panels, some electrodes, and some cryo-pumps (ok don't actually know what cryo-pumps are, but they sound like the cool). Can I have $5m please.
To all those that didn't read the article BTW, the assumption for the design is that the water comes from the moon, whether that pans out or not isn't the problem of people submitting designs.
Oh no... it's the future.
Delivering so huge amount of fuel to space orbit will cost really much. And is there enough fules on the planet to bring a project like this to life&
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
Tie a gas can to a rope and just huck it up in to space. It might take a try or 2 to get it that high, but it'll eventually work. And the rope is so we can bring it back so we don't little space. See? Fast, simple, and environmentally friendly. Please send me my $5 million money dollars in small, non-sequential, unmarked bills.
Nullum magnum ingenium sine mixtura dementia (There is no great genius without a mixture of madness) - Aristotle
How about generating aritifical gravity by putting the entire gas station into a spin? (Yes, Arthur C. Clarke taught me this :-) There'd probably be some problems with this however.
Swedish plasma phys. PhD student; MSc EE; knows maths, programming, electronics; finance interest; seeks opportunities
...then it's less likely to screw up.
Seriously, how many times have we heard of various satellites/probes that have screwed up due to tiny/stupid errors? I'm talking about the kind of errors that would never happen in private industry, like probes crashing because one group of people is using metric and the other imperial. Such errors would cost people their jobs in a private enterprise, but typically not for government-funded projects.
Don't you just hate it when people reply to your signature?
why not build a huge super tall space elevator... naaa, nevermind...
The article says one of the problems is figuring out how much fuel you have in zero G because it's all floating around inside the tank. Call me crazy, but can't you just rotate your station and then check the pressure on the inside walls of the tank? Not like centrifugal force is some newfangled idea or anything. It's not like it would even have to rotate particularly fast. Sheesh, do I have to figure out everything for these guys?
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.
I hope they'll properly tax those damned fuel-guzzling Space Urban Vehicles!
One line blog. I hear that they're called Twitters now.
Has there ever been one Slashdot article without a greeting to our "new overlords"?
Wouldn't there be a problem with the fuel depot maintaining a stable orbit? As it offloads mass to another vehicle, it seems its orbit should change because of its changing mass. Something to do with conservation of momentum.
They say the first thing to go is your penis. Well, it's either that or your brain. I forget which...
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.
It was (at least) once proposed that NASA have the shuttle carry the "empty" fuel tank into orbit & have them assembled into a "station" at some later point.
A small semi-dumb "tug-bot" could do the dragging into similar orbits part. However, it might take a few humans with wrenches to do the rest.
The cost would have been a reduced payload capacity for the shuttle(xx percent??). However, how many times have they launched at "full" capacity?.
Cryo fuels would be interesting due to the long term effects of extremes heating & cooling, but a few "sun shades" might help there. Using bladders for other fuels would prob work for a "quick" fix.
Google is taking over the world already, why not expand their market share to space? I can see it already: "Mars Orbiter Googled in Midflight." From it's web server cell phone, of course.
Touting MyEclipse AJAX Tools
Aren't all the problems the same as those that exist for fuel tanks in spacecraft? In which case, they've already been solved in existing craft, so just modify their fuel tanks.
I'm sure spacecraft can measure fuel levels in zero g - would seem odd not to be able to. And you have to suck fuel out in just the same was regardless of if it's going to an engine or another fuel tank.
Is that all they have to offer? Why not make a business of it instead, and charge astronauts impossibly high amounts for fuel. It would be a monopoly, after all.
I wonder if the Bigelow folks could do this? They may have at least the components of a station ready to go. www.bigelowaerospace.com
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.
Just launch one of these into orbit. Can I have my $5 million bucks now?
The problem looks almost park barrel easy for $5M. As far as I can tell, the contest is for the station design alone. The problems described in the article such as gas in the fuel and measuring remaining fuel sound ~trivial to me (I have thought of three^Wfour cheap solutions while writing this). The hardest part seems to be containing the hydrogen effectively (two solutions plus whatever people smarter than me have already thought of).
The biggest problem as others on this board have already observed is going to be supplying the station with mass.
If it were possible, it would really only be useful for solid engines. Liquid-fueled engines would be severely damaged by even molten materials that had been structural.
Stupidity Point 1:
YOU USE FUEL TO GET IT THERE!
Stupidity Point 2:
(Meteor) --> [Fuel Tank in Space] = BOOOOOOOOOOOOOOOM (and/or) end of moon
Earth's gravity well is at the edge of bichemical propulsion capacity. The best systems to date still only lift less than 10% payload weight of the launch vehicle.
This fact means that unless rocket technology and materials building became absurdly cheap it will never provide the basis for a massive launch capacity needed for ideas like colonization or even large scale outposts on other planets at anything approaching economicaly viable costs.
True reuseablity is about the only thing that could make this pitiful payload capacity work at all. At least then vehicle construction costs could be amortized over the course of multiple launches which could drop payload costs dramatically. Supplying a fuel station with throw away rocket technology is like suggesting the gas station down the street get replenished by buying a new tanker truck to deliver its fuel every time.
Sure the truck can be made less reliable. But you still have to build a working vehicle each time. This will never work for anything but the most rarefied needs.
We need a true shuttle system. One which can sustain multiple missions with a simple re-fuling turn around process. The present 'shuttle' is anything but.
The other option as always is new technology. None have really shown up as far as a primary lift capacity. All new ideas other than perhap NERVA or Orion have all been different versions of the same idea of combining chimical propellants. Short of a new and as yet unknown fuel, chemical propulsion has reached its known limits in rocketry.
I don't ask you to be me. I only ask you not expect me to be you.
...(or john)...
Geez, there are already Johns and Hos in space even before the first space hotel is launched???
Oh well, what the hell...
Not being an engineer, or even a particularly practical mathematician (but ask me about finite automata! ), I'm not sure about the logistics of this. But hey, why not?
Heres a clicky for other challenges in NASA's Centennial Challenges programme.
Notice the very doable (slashdotters?) robotics one. 250k.
Actually the station could use solar power to sustain and generate the torques needed. The Hubble uses two flywheels, spin maintained and generated by solar power, to adjust the telescope's position. The same could be done with a space station, except more power would be needed as well as other engineering feats such as bigger flywheels (or lots of smaller ones).
Even if you conquer Zero Gee with Artificial Gravity, you haven't entirely solved the Toilets in Space problem. Especially when it comes to filling stations in space. After all, filling stations on earth often don't have the cleanest toilets. How are we going to keep them cleaner in space?
Wait, don't say it! I'm one orbit ahead of you... Illegal aliens: Doing the jobs our astronauts (and filling station attendants) won't do.
Kent M Pitman
Philosopher, Technologist, Writer
Everybody keeps going back to using water, cracking it via solar electricity into oxygen (gas, or cooled/compressed into a liquid) and hydrogen (again, as a gas, or (unlikely) as a liquid.)
Where's the actual rocket fuel here? Last I recall, oxygen makes a great fire enabler, but pure oxygen itself doesn't really burn - it makes fire possible, makes fires better - but there needs to be some sort of fuel to burn in the first place. And as for H2 - if memory serves me correctly hydrogen + oxygen + spark doesn't explode, it implodes. It is a neat trick for high-school chemistry students, but implosions aren't particularly useful for creating thrust.
Glonoinha the MebiByte Slayer
1. The dig had to have a minimal environmental impact -- enough to satisfy Cambridge and the Cape.
2. The tunnel has to go through reclaimed swamp silt. For a significant part of it, they had to drill holes and fit pipes into the ground in an area, then pump a supercooled solution (not sure if they used saltwater or glycol) through the pipes and freeze the ground hard enough to dig through as they placed the tunnel.
3. The tunnel has to go through the center of a major city which is the economic engine for an entire region -- basically everything north of Hartford -- that has only 1 major central highway in and out, and a terrible lack of bridge and tunnel paths already.
4. The tunnel has to replace an elevated highway which is aptly named the "Central Artery" and is the single major traffic corridor through the city, but it has to do so without stopping traffic on that existing route.
Hell, the TEMPORARY bypasses are more complex and expensive to build than most highways.
When its done, however, what has always been the biggest blight on the city from an appearance, safety, and noise perspective will be gone.
What was an elevated 6 lane roadway will be green space. You will be able to walk from the Charles river all the way to South Station and Chinatown, stopping in the North End for an Italian dinner, at the Aquarium, at Fanuel Hall, at Rowe's Wharf, and at the Haymarket. Doing so now would be a noisy, dangerous, ugly nightmare of a walk. Doing it in a few years will be literally a walk in the park.
The problem with quotes on the internet, is that nobody bothers to check their veracity. -- Abraham Lincoln
The T-space consortium already proposed this in their bid for the CEV program. NASA should concentrate on ideas that haven't already been given to them.
http://www.transformspace.com/
This cruel chicken-and-egg dilemma is what is holding us back.
http://www.newpath4.com/millenialdawnpowerandlight secure21.htm .
Needs some adjusting for reaching plaid.
which "it" from the 60s are you referring to? Ion propulsion or what?
we'll send punks with gasoline cans and syphons up there and "liberate" the russian and chinese orbital fuels. heck, with a coat hanger and wire cutters they could even jack spacecraft.
I would suggest fuel might be more likely to come from either: the moon, or a rocky asteroid, by chemically breaking down rock matrices. Of course, to do that efficiently might require something a bit more energetic than sunlight, one might want to go whole hog for nuclear fission (fusion) reactors.
2H2 + 02 results in 2 water molecules and a decent amount of energy. Hydrogen combustion cars (not fuel cell cars, which are actually electric) use this technique; it produces enough energy to drive the pistons. The reason you see an implosion when a match is inserted into an inverted test tube is because the ware vapor produced cools very quickly, and at atmospheric pressure, water is far denser than H2 or O2. Thus a given mass of the gasses produces a much lower volume of water. However, in space the water vapor produced by the combustion is EXTREMELY expansive. It still cools rapidly (much more so, in fact) but a great deal of thrust can be produced by forcing it (at pressure, within the reaction chamber) out a rocket nozzle. Once exhausted it can cool all it likes; by then the ship is blasting out more water vapor and the rapidly freezing water is far away.
There's no place I could be, since I've found Serenity...
So how high would it need to be to have the top end in a total vacuum and therefore not need any "cap" on it?
GeoSync is 35K kilometers(22k miles) above the surface, yet there's still enough atmosphere there that satellites have to be boosted occasionally. Still, much above the 20 miles you'd probably be pushing the break-even point. It takes about a 150 km of height before earth's atmosphere is thin enough to be 'low drag' to earth's satellites. So you'd need to go 93 miles up, or nearly 5 times as high as the 20 mile tower, to eliminate that remaining 1%.
At some point it's easier to put a cap on the tower, even if you'd have to remove it before launch. It's likely that the tower would be at least somewhat leaky, requiring constant pumping no matter what.
At some point it'd be easier to drop a cable from orbit to mate with the tower.
Is this more or less feasible than a space elevator?
Well, theoretically speaking we could build at least a 'short' tower now, and experience at least moderate benefits from it, even if you're just winching the rocket up to the top for launch in thinner atmosphere. We still have a while to go on material strength to build a cable type elevator.
I'll note that these would be 'zero power maintenence' options. IE you could at least theoretically remove power from them without nasty crashing problems. There are some ideas that require much less in the way of structural materials, but require more or less constant power. Another thing to note would be that, while we could build a beanstalk for the moon/mars now, earth's gravity is slightly too high, so a combined approach will probably be the end solution. Something like a rail or powered cable(see link) approach to get into orbit, then a 'short' cable that doesn't go into the atmosphere(the most expensive part). In that case it'd be used more for launching vessels to other planets, though it'd still be usefull for satellite placement and you'd likely have a huge base in the middle.
I don't read AC A human right
Look up Superfluid On-Orbit Transfer (SHOOT) which flew on the Space Shuttle Endeavour - STS-57. We demonstrated almost all of this ... for Helium.
This also included the first AI system in space: a fairly sophisticated autonomous system which controlled the transfers as well as diagnosed and recovered from problems.
Helium has some nice properties which made it easy to determine the amount of helium remaining by injecting a very small amount of heat. But we also compared this to a "level" determined by firing the thrusters on the Space Shuttle to settle the liquid and using an electronic version of a dipstick.