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NASA Space Science

NASA Looking To Build 'Gas' Stations In Space 201

Posted by CmdrTaco
from the hope-they-have-pay-at-pump dept.
coondoggie writes "Fuel is a major issue when it comes to long-duration spaceflights — its weight is a problem for launch and once a spacecraft runs out of fuel there's no place to get more. That's where in-space 'gas' stations located at strategic spots along a route would be a boon to spaceflight. Which is exactly what NASA is looking to do by beginning to solicit proposals for what it calls an In-Space Cryogenic Propellant Storage and Transfer Demonstration that will lay the groundwork for humans to safely reach multiple destinations, including the Moon, asteroids, Lagrange points and Mars."
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NASA Looking To Build 'Gas' Stations In Space

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  • by splatter (39844) on Tuesday April 26, 2011 @11:54AM (#35942998)

    Aww man I'd hate to smell the mens room in that place.

    • by Kagura (843695)
      Space. Space space. I wanna go to space. Dad, I'm in space! I'm proud of you, son. Dad, are you space? Yes, now we are a family again. Space space. Yes, please, space. Space. Space. Good space. Here come the space cops. Space cops help. Help. Putting the system on trial. In Space. On Trial. Guilty. Of being in space. Atmosphere, black holes, nebulas, astronauts, the big dipper. THE BIG DIPPER.
  • Space dock (Score:3, Interesting)

    by Anonymous Coward on Tuesday April 26, 2011 @11:58AM (#35943032)

    One way to solve the launch weight problem is to not launch them. Build spaceships in space and you can build ships that aren't possible if you have to launch them from the Earth.

    • by gmuslera (3436)
      Could be interesting if eventually you could build spaceships taking materials from i.e asteroids. With a bit of care one could be turned into another (far smaller) moon and use it as source for raw materials, if of the right kind. Not sure if the fuel itself could be acquired in a similar way eventually.
    • Whoring for Karma? why not....

      We'd need one of these [wikipedia.org] before we can start building ships in space in sufficient numbers to be worth it. There's already numerous groups around the world looking in to the technology and feasibility of doing it, and several proposed sites around the world. Alternately, we could also try a launch loop [wikipedia.org], but either way, our engineering is simply not capable of building something like that yet. "Yet" being the operative word.

      As for why we don't build ships at a space station? The l

      • As for why we don't build ships at a space station? The logistics of keeping a staff in orbit, and blasting parts into orbit so they can be assembled by staff in orbit, then blasting fuel into orbit so the ship can be fuelled, then blasting a crew and food supplies into orbit so that the ship can actually be launched are far more expensive than simply building craft on terra firma and blasting the whole kit and kaboodle into space. Until we're ready to start manned missions to deep space, it's simply not worth it, economically.

        The logistics do seem quite daunting, but at the same time, removing launch and atmospheric capabilities from the ship's requirements may lend itself to new designs that handle space travel much more effectively, thereby making deep space missions much more practical. As well, the technology that goes into creating the space shipyard will contribute to the colonization of the moon, Mars, and many other worlds; not to mention that the facilities may well serve to produce much of the equipment necessary for s

      • I've always been a bit skeptical of elevators. I mean - they are so damned massive, and there is so much stored energy in it - if and when something bad happens, you have a cataclysm on your hands.

        The mag lev idea seems a whole lot better, but I'm still a bit skeptical.

        I've always favored a railgun concept, mounted on or dug into a mountain. You still have an appreciable quantity of energy being expended in case of an accident, but it would be "aimed" outward, rather than inward. More, I believe the init

  • How much time would that actually add to a trip to say Mars?
    As I understood it, you would spend more or less half the trip speeding up and at the 50% mark flip the ship and slow down. That makes it seem like slowing down takes a really long time. I assume since there is either A, very low G forces and thus it takes for ever, or B, the power needs to kept down since puny humans cannot take high G situations very long.
    Either way, making a complete stop 1/2 way would make you need to flip the ship at the 25% m

    • First, you are assuming the mission is manned, and thus the maxG=1 or close to it. If you take that assumption away you can have a much smaller mass and this acceleration can be increased.

      A bigger problem for outside of lunar orbit is the fact that you would limit yourself to very specific trajectories. That would mean you either have a very small window or a much longer flight. Both of which are problematic for the purpose of decreasing flight time and increasing flexibility.

      Parking the stations in orbit

      • by mark-t (151149)
        Even *IF* the maximum G were 1, do you know how fast you could get to mars if you could actually maintain that acceleration and deceleration for half of the trip? Your average velocity would be faster than anything mankind has ever achieved outside of a particle accelerator (about half of 1% of the speed of light), and you'd reach the halfway point in less than 2 days.
      • by h4rr4r (612664)

        Why do humans onboard mean the maxG=1. I have experienced 5 and that was too much, but people could easily handle a maxG of 2 or so.

        • by mark-t (151149)
          In a word. Comfort. Anything even modestly over a g would not be livable for a prolonged period of time (that is, anything beyond a few hours).
    • Why not put the "fuel station" in orbit around Mars. Send up an unmanned ship loaded with roughly half the amount of fuel, food, oxygen, water, etc. needed for the mission and put it in orbit around Mars. Later, once everything is verified as arrived and safe, launch a manned ship with roughly half the amount of food, fuel, etc needed for the mission and let it dock with the unmanned station when it gets to Mars to restock. This will allow you to carry roughly half as much consumables on the (by necessity

    • The problem isn't so much in getting from point A to point B in space, as it is with getting to space in the first place.

      Let's say you want to send something to Mars. You've got a 1-ton payload... And then it takes 1 ton of fuel to make the trip from Earth orbit to Mars. So you need to lift 2 tons into Earth orbit.

      Of course... If you had an orbital gas station you could just lift 1 ton into orbit, and then fuel up at the gas station.

    • Re:Time? (Score:5, Interesting)

      by Nyeerrmm (940927) on Tuesday April 26, 2011 @01:02PM (#35943786)

      You're misinterpreting how most current spaceflight is done. At present only asteroid/comet/deep space missions use any form of continuous thrust, in the form of low-thrust ion or Hall-effect thrusters. Anything to a major gravitational body will still rely primarily on high-thrust impulses from traditional chemical rocket motors. Though technology on the horizon may be changing that, it is the current state of affairs.

      The path to Mars using chemical thrusters is very straightforward -- if you look up the Hohmann transfer, thats basically the way its done. Leave Earth orbit so that your sun centered orbit is elliptical and touches the Mars orbit. When you get to Mars speed up again to catch up (in practice you do a capture burn and do it in a frame where it looks like your slowing down, but nonetheless). If you want to be really clever sometimes you do a major maneuver in the middle to allow you smooth out some of the problems that occur because the planes of the orbits aren't quite the same. All throughout there you do small maneuvers to keep on course. If you want to go faster, you can do faster shorter transfers, but it requires bigger burns on both sides.

      However, in order to do this with chemical thrusters, you need a lot of fuel. A 1500 kg probe requires an extra 1100 kg of fuel just for the catching up maneuver, and probably > 3000 kg for the departure burn (I don't have data on that at hand right now). Its logarithmic so if you wanted to get that probe back to Earth you'd have to bump those measures up by factor of 2 or 3. Throw in landing and departing the Martian surface and it just gets uglier. This is why a Mars Sample Return mission is so hard -- you just can't stack that much mass on top of a launch vehicle.

      Imagine instead though, that you had a cheap way to get fuel to orbit. 'Space Guns' and other such ideas are primarily ridiculous because they apply 100s of Gs that would kill a person or most hardware. Fuel won't care though -- so use high-cost rockets to get the people and high-value equipment to orbit, fill up empty (expandable?) fuel tanks there with cheap fuel launches, and then get on your way. Maybe ship some more fuel to Mars, but I'm not sure the numbers make sense for that. However, you could definitely use this technology with technology to extract fuel from the Martian environment to make the return leg easier though.

      Thats why fuel depots are interesting for space exploration.

      • Re:Time? (Score:5, Interesting)

        by teeks99 (849132) * on Tuesday April 26, 2011 @02:29PM (#35944866) Homepage

        You pretty much nailed it all on the head. The only thing that I wanted to add was that there has been one probe to move between two massive bodies (Earth and the Moon) using a continuous thrust system: the SMART-1 [wikipedia.org] probe with its Ion engine [esa.int]. The downside: it took 13 months (it only took the Apollo astronauts a couple days) and used a series of really strange [moontoday.net], constantly expanding orbits (basically a spiral), on the plus side it only took 1/10th of the total propellant mass that a chemically powered spacecraft would.

        Ion/Hall/Plasma [adastrarocket.com] thrusters are great for moving cargo where you don't care too much about how long it takes (especially in the beginning of the mission). This type of technology could easily be used to move fuel to one of these "Gas Stations" in earth, moon, sun, or mars orbit. You could start this years before the need date (before you get busy testing out the manned space craft) then the chemical fuel could already be there when you're ready to launch the manned space craft.

    • The problem trying to be resolved by in space fueling is the elimination of the need to carry it with you from earth on the same launch. Take for instance the most immediate need for this capability, satellite refueling. Presently the lifespan of a satellite is no longer than the fuel supply it was launched with. After this runs out it is no longer possible to correct for orbital decay, nor collision avoidance--an ever growing problem. Launching satellites with less fuel and being able to refuel them in

    • You don't need the fuel at the half-way point. You need it in orbit - at the destinations, as you say. Besides, you don't need to come to a stop to fuel. There's no such thing as stopping in space. All you need to do is match velocity with the tanker. The tanker could have been sent beforehand, or it could be sent afterwards
    • It wouldn't be necessary to "stop" even if you were to refuel mid-flight. The refueling vessel would be placed in opportune orbit--around the sun, around a planet, etc.. An inbound vehicle would simply intercept the refueling vessel's orbit, refuel, and continue on it's merry way.
      • by pablo_max (626328)

        Would he not burn up all his fuel staying in orbit? I assumed he must use a Lagrange point.

      • It wouldn't be necessary to "stop" even if you were to refuel mid-flight. The refueling vessel would be placed in opportune orbit--around the sun, around a planet, etc.. An inbound vehicle would simply intercept the refueling vessel's orbit, refuel, and continue on it's merry way.

        It would be harder to put a refueling vessel in an "opportune orbit" than to get it to the destination.

        And it would probably require more fuel to match orbits with the refueling vessel in an "opportune orbit" then return to your o

  • by Covalent (1001277) on Tuesday April 26, 2011 @11:58AM (#35943038)
    This idea is an excellent one...build your spacecraft in orbit and then launch it from there with fuel from an orbital gas station. Significantly less danger for the crew, much faster travel, and shorter periods in outer (read: Cosmic Radiation) space. But it isn't politically sexy, so it probably won't happen.
    • by FleaPlus (6935) on Tuesday April 26, 2011 @01:48PM (#35944310) Journal

      Actually, not only is it not politically sexy, but it's outright politically dangerous. Having fuel depots allows you to use existing rockets for exploration beyond low-Earth orbit, alleviating the need to develop heavy-lift rockets. A number of politically-powerful congressional districts (and congressmen) are heavily banked on NASA building a heavy-lift rocket from Shuttle-legacy components, while that isn't the case for fuel depots. I predict it won't be long before this particular effort is squashed by Congress, perhaps even outright banning it like they did with the TransHab inflatable modules [wikipedia.org].

  • by jafo (11982) * on Tuesday April 26, 2011 @11:59AM (#35943050) Homepage
    In WWII, the US was building up a fuel store by fueling up B52s and flying them across the Himalayas. But, depending on weather conditions, sometimes they would need to take on fuel at the depot to make the return trip. The implication in what I've read about this is that they were spending the majority of the fuel on the trip, to deposit a little fuel at the destination, like driving across the state to deliver a couple of gallons of petrol.
    • In WWII, the US was building up a fuel store by fueling up B52s and flying them across the Himalayas. But, depending on weather conditions, sometimes they would need to take on fuel at the depot to make the return trip. The implication in what I've read about this is that they were spending the majority of the fuel on the trip, to deposit a little fuel at the destination, like driving across the state to deliver a couple of gallons of petrol.

      First, we didn't have B52 bombers in WW2. You probably meant B29s

    • by LWATCDR (28044)

      No they didn't.

      There was no B-52 during WWII.
      There was no B-52 in service during the Korean war.
      The B-52 didn't enter service until the 1950s and still is to this day.

      Durring WWII the US would fly fuel of the "HUMP" in a number of planes including the C-46, B-24 and the B-29.
      Saying that they used B-52s to fly fuel in WWII is as dumb as saying that your parents used their PC to log onto CompuServe back in the 1950s
      Those that do not know history will just make it up as they go.

    • by ari_j (90255)
      That's a really interesting story. I had to do some searching to find more information, as I knew it couldn't be (jet-powered) B-52s handling the task during WWII. It sounds from this Wikipedia article [wikipedia.org] that a variety of aircraft from C-3s to C-87s did the job, with the C-47 being the workhorse.

      When I saw this article, though, about fuel stops in space, I was immediately struck with the thought that it would take a lot more fuel to decelerate enough to dock and re-accelerate than it would be worth. It
      • by teeks99 (849132) *

        That's where the "Strategic Spots" come in. There are certain points along the orbit from earth to X (moon, mars, asteroid, etc) where it would take extremely little thrust from the space ship to drop by there (stop is the wrong word).

        Also, as others have mentioned, it would be possible for the "Gas Station" or at least a module of it to come to you as well.

    • by Nimey (114278)

      Wrong. They flew C-47s and C-46s over the Hump to support (among other things) the B-29 bases in China, and I would expect that the cargo planes /would/ need to refuel - people forget how short-ranged planes were back then.

    • In WWII, the US was building up a fuel store by fueling up B52s

      Yes, it maintained a lot of "fuel" to keep those up standing.

      and flying them across the Himalayas.

      Well, I hope that they didn't break any fingernails, when the pilots tossed them out of the planes . . . Himalayas . . . um, did they have sleds along with the parachutes . . . ?


    • One of the plans for the mission to Mars is to make the fuel on Mars, from the soil there. The chemistry has been tested on earth. The original plan was to put men on Mars and make the return fuel then, while some 300-500 days pass while the earth comes back around for the return fight window.

      Given robots go first and make fuel why not lift it with to a space station for refueling. This way we get the fuel on sight, out of the gravity well. This fuel can be used for landing, blastoff and return. Ge
      • Salutes, bobs666. I get so frustrated with people who want to use robots for space exploration INSTEAD OF men. But, my own prejudices have blinded me a little. Of course it makes sense to automate something like this with robots, to save time and expense for the humans who follow. And, further, robots should be used for initial attempts to explore, just as we have already done on Mars. There is nothing wrong with using robots at all. But, when the robots have prepared the way, I most certainly want to

    • In WWII, the US was building up a fuel store by fueling up B52s and flying them across the Himalayas.

      Wow, I didn't know the US had time travel during WWII, getting aircraft that were still over ten years in the future like that.

  • There is no reason not to develop remote-manned tech for another hundred years and THEN send human tourists with vastly improved technology.
    We need remote-manned and robotic tech on Earth, now and for the future. We MUST have it to exploit the PERMANENTLY hostile environment offworld. Humans will have to live in protective enclosures anywhere they go, which reduces them to machine operators either way.
    Humans explore nothing, they are passengers. Ditch the terrestrial model of "wooden ships and iron men" bec

    • you miss the scope of this. there is nothing to say that robotic missions would not need extra fuel. I posted above in more detail, but I can see missions which return from planets/moons to earth as options. Missions with multiple stops (all of jupiters/saturns moons being mapped in details would be awesome), LEO missions where you move around a lot but dont want to waste fuel mass carrying extra fuel mass (space planes, LEO cleanup vehicles, sattelites).

      Also allows for small ships to go up the gravity well

    • Remote-manned (by which I assume you mean remote controlled like radio controlled airplanes and submersible remote operated vehicles) is impractical due to propagation delay. The Moon is 1.3 light seconds away, meaning a round trip signal is almost 3 seconds. Mars is anywhere from 8 to 40 minutes round trip time. That lag makes remote manned impossible. By the time you saw the rock, the rover would have crashed into it as much as 20 minutes earlier Robotic missions will need to have significant on boar
    • by Reeses (5069)

      It could be argued that in the days of "wooden ships and men" the men were less expendable than they are now.

      We're nearing a world population of 7 billion. If you think a few thousand of those aren't "expendable" as long as they enter into the deal knowing all the risks, then you need to do some math.

      They're far more "expendable" than they were back when the world population was only a few tens of millions.

      We're becoming progressively more worthless.

      And the "Wooden ships" part being more expensive is becaus

    • by Runaway1956 (1322357) on Tuesday April 26, 2011 @02:45PM (#35945100) Homepage Journal

      Men and ships are just as expendable today as they were 100, 300, or 600 years ago. It is only your own vanity that makes you think that men's lives are worth more today. As for the expense of the ships - today's ships cost a lot of bucks, yesterday's ships cost a lot of currency as well. That famous Armada that was sunk in the storm off of England's coast was a substantial part of the kingdom's budget. You'll note that the Armada wasn't replaced, in fact, couldn't have been replaced as quickly as the United States replaced her damaged fleets after Pearl Harbor.

  • I've been reading/watching a lot of old sci-fi lately and one of the features that keeps popping up is the idea of a Lagrange point making a moon/mars trip possible.

    I mean if you wanted to go to Mars, land and come back you wouldn't do it quite like a trip to the moon. Ideally you build the ship in space at a Lagrange point then shuttle the fuel, men and equipment up there. Then send a ship with a lander capable of breaking Mars orbit AND either a decent sized orbiter for the trip back or park another Lagra

    • by drinkypoo (153816)

      It probably makes sense to build it at the Earth-Moon L1, assuming materials are coming from Earth. Otherwise, L2, since they must be coming from the moon... Hmm, looking at Wikipedia, I see that L2 is proposed as the ideal propellant station site :)

    • I'm not sure what the draw is with Lagrange points. L1, L2, and L3 (the ones in line with the primary and secondary bodies) are dynamically unstable. It's not like you can park there. L4 and L5 points are much better because they are dynamically stable points, however nobody talks of placing a fuel depot there. You're much better off just building everything in Earth orbit. Sure, send a return vehicle ahead. Send fuel and supplies ahead. But don't bother parking at Mars/Phobos L2, just keep things si
      • by FleaPlus (6935)

        L1, L2, and L3 (the ones in line with the primary and secondary bodies) are dynamically unstable. It's not like you can park there. L4 and L5 points are much better because they are dynamically stable points, however nobody talks of placing a fuel depot there.

        Actually, assuming you're talking about a hydrogen/oxygen fuel depot, you'll have a few pounds of propellant boil-off every day (out of several tons total). You can redirect the boil-off for station-keeping, and it pretty much meets the requirements fo

    • I mean if you wanted to go to Mars, land and come back you wouldn't do it quite like a trip to the moon. Ideally you build the ship in space at a Lagrange point then shuttle the fuel, men and equipment up there. Then send a ship with a lander capable of breaking Mars orbit AND either a decent sized orbiter for the trip back or park another Lagrange point in relation to Mars before you even go, stop there and gas up and leave.

      Easier to build it on the moon. And since there is water on the moon, easier to fu

  • It seems like a wasteful solution if you imagine sending up rockets with fuel, but we could freeze it solid and shoot it up with a magnetic rail-gun, perhaps ...

    • Or LEO with a super-cannon...

      http://en.wikipedia.org/wiki/Project_HARP [wikipedia.org]

    • Also of note, People take a lot of resources to survive. So the trick with people is to move then quick so they use less resources. These could be put into orbit and take a decade or two to get into position. Have it sling shot around some planets and enough fuel (non-storage) to "Park It" in spot. For human travel taking a decade or two is way to long. We need fast and light ships to get us to say in mars in a year or two.

      • Also of note, People take a lot of resources to survive. So the trick with people is to move then quick so they use less resources. These could be put into orbit and take a decade or two to get into position. Have it sling shot around some planets and enough fuel (non-storage) to "Park It" in spot. For human travel taking a decade or two is way to long. We need fast and light ships to get us to say in mars in a year or two.

        Umm, no.

        the minimum energy hohmann transfer orbit to Mars takes 8 months and change.

  • by EWAdams (953502) on Tuesday April 26, 2011 @12:04PM (#35943120) Homepage
    They sent out advance parties to place depots along the route, over 100 years ago. Totally obvious thing to do. I can't believe it has taken this long for Nasa to clue in.
    • How much energy did it take to keep the polar caches in place? That's the difference. NASA can't just hang it up there, turn on the anti-gravity, and find it there in 10 years. I mean... explorers sailed to new worlds for centuries using nothing but windpower. Why doesn't NASA do the same thing...

      Oh, right... they also have to take their own oxygen, and don't have a medium upon which to float. Gotcha...
      • by Arlet (29997)

        Actually, if you put things in orbit, outside the atmosphere, they just "hang" there forever.

        • And there are such things as solar sails... and technically there is a Dirac sea [wikipedia.org]... :P
        • Nope. All orbits decay. Some on the time scale of the age of the sun or the universe, but space is not a pure vacuum and all orbiting bodies will eventually fall back down.
          • by Arlet (29997)

            But we're not talking about the age of the sun or the universe, but just a couple of years, maybe decades, at most. On that timescale, there are plenty of stable orbits.

  • Smells like chicken! [slashdot.org]
    • Re: (Score:2, Offtopic)

      by $RANDOMLUSER (804576)
      Can someone please explain to me the recent spate of articles about NASA from NetworkWorld?????????

      Oh, I get it "Michael Cooney" == "coondoggie".
  • Cryogenic

    That's the hard part. Keeping it liquid. Would be a bummer to arrive at mars, get ready to fuel up, and oops we don't have any gas to get home.

    The other mysterious part is no mention of water / oxygen / nitrogen / food / medkits / spare parts / etc. You'd think a "supply cache" would have more than just fuel in it.

    • by 0123456 (636235)

      That's the hard part. Keeping it liquid.

      Sunshades and a refrigeration plant should work. I believe that's what the Apollo-derived Mars mission plans were going to do so that they could use the LOX/LH2 S-IVB stage for Mars orbit entry.

  • Self Serve or Manned ?
  • I don't think I quite get how this is more economical. Is it actually cheaper to send up a bunch of smaller rockets with fuel as payload than it is to simply send a bigger rocket with enough fuel on it? Can somebody walk us through the math?

    • by Arlet (29997)

      Overall it should be the same. Sending the fuel first still requires the same total take-off mass as sending the fuel with the ship.

      The advantage is in the logistics. You can send the fuel ahead of time, using a slow trajectory, and then launch your main ship on a faster trajectory. Or, when the fuel rocket fails, you can send another one before sending your main mission.

    • Re:economics (Score:5, Interesting)

      by 0123456 (636235) on Tuesday April 26, 2011 @12:44PM (#35943584)

      Is it actually cheaper to send up a bunch of smaller rockets with fuel as payload than it is to simply send a bigger rocket with enough fuel on it?

      Yes.

      Flight rate is generally more important to launch costs than size. A small rocket you can fly a thousand times a year will cost you far less than a big one you fly once a year simply because you can mass produce them and reuse them several times before you throw them away, rather than custom-building a new one every time you launch it.

      If I remember correctly, the plans for reusing Saturn V stages made no financial sense until it was flying about once a month, for example; at NASA's actual launch rates the savings from reusing them would be less than the costs of developing the technology to do so.

      A further issue is that by splitting your hardware and fuel across multiple launches, one exploding rocket doesn't lose your entire multi-billion dollar Mars mission. A near guarantee of losing one payload out of a hundred launches is likely to be better than a 1% chance of losing the entire thing.

    • by AGMW (594303)
      You can send a bunch of cheap(er) unmanned rockets with fuel as the payload and store it in orbit, then you can send a more expensive (reliable) manned craft with the crew. Money and risk reduced.

      Better yet, if we're looking at Mars - why not send a bunch of comms- and GPS-style satellites and get them in orbit so when we get there we've got good location and comms stuff all sorted. Send a copy of the ISS there too, but this time as the base to drop people to the surface and drop off place for supply vess

    • Humans are an expensive pain the arse to launch. The smaller their vehicle, the cheaper, and safer they become. Non-human payloads do not require the safety (nor life support) of a human rated vehicle. This makes them significantly cheaper. The expense of a rocket grows exponentially the larger you make them. Smaller rockets are also easier to mass-produce.
      • by 0123456 (636235)

        Non-human payloads do not require the safety (nor life support) of a human rated vehicle. This makes them significantly cheaper.

        Except the 'human-rated' shuttle has not proven to be significantly safer than a typical not-human-rated launcher (i.e. around a 95-98% chance of not catastropically failing).

        'Human rating' is a mostly bogus concept, though I'd agree that if you're just launching fuel then you might be willing to live with a less reliable launcher if that significantly reduced costs. If you're launching a billion dollar comsat, you don't want to put it on something that you wouldn't risk putting NASA astronauts on.

    • by FleaPlus (6935)

      I don't think I quite get how this is more economical. Is it actually cheaper to send up a bunch of smaller rockets with fuel as payload than it is to simply send a bigger rocket with enough fuel on it? Can somebody walk us through the math?

      Absolutely. Remember that development costs tend to be very important when it comes to rockets. For example, the recently-cancelled heavy-lift Ares V rocket NASA was building was projected to cost at least $32B to develop (ignoring operations costs). This was for a rocket with 188mt capacity. By comparison, SpaceX recently announced a smaller rocket (53mt capacity) which will launch at $100M/flight starting in 2013. Instead of spending $32B to develop a bigger 188mt rocket, NASA could instead spend that mon

  • Starbase? Captain's Log, Stardate 2054.6. Visited orbiting refueling station on the way to a planned stop at Mars. The attendant did a horrible job on the windshield. Can't see a damn thing...I need better service station attendants. Mr. Spock, windshield status?....
  • by starglider29a (719559) on Tuesday April 26, 2011 @12:32PM (#35943416)
    Disclaimer: degreed rocket scientist without time to do the math.

    Rather than
    1. lift a surplus of propellant to a gas station
    2. have the Mars mission lift with just enough energy to park at L5, Phobos or whereever,
    3. refuel and thrust away to mars... Instead:
    4. launch the required propellant on nearly the same trajectory as the mission, once trajectory confirmed...
    5. Launch the Mars mission with enough energy to travel to Mars
    6. Rendezvous on the long trip, refuel, carry on

    Advantages: putting the heavy lifting on the booster on Earth (where logistics is easier), don't waste energy stopping/pausing and restarting the trajectory.
    Disadvantages: You better be sure you can refuel in flight.

    • by khallow (566160)

      Disadvantages: You better be sure you can refuel in flight.

      Among other things that means you may need to launch extra propellant, just in case. I think that alone would negate the slight propellant savings from bypassing LEO and going directly to Mars.

      The primary advantage of LEO assembly is that you don't have to go beyond LEO until everything is in place and works. Even a crew lost during a launch failure can be replaced. The scheme also has much easier and more forgiving logistics. You don't have to launch from Earth to hit a small launch window to a particul

  • by Anonymous Coward

    This is the kind of capability development that is appropriate for a space agency to do.* The lack of orbital refueling capability limits all missions to what we can lift in a single payload. Developing the capability won't be easy or cheap, but with the capability in hand lots of other mission possibilities will be unlocked - for both public ventures and for private enterprises. It's a *much* better way to spend a limited budget than developing a new booster would have been.

    Next up: Automated in-orbit asse

  • by trims (10010) on Tuesday April 26, 2011 @12:49PM (#35943650) Homepage

    If we ever plan to go to Mars (or other extra-Earth area destination), we need to ship the vast majority of consumables ahead of time. In essence, we need KwikiMart outlets in space.

    More to the point: consumables and human space travel have very different criteria: Consumables:

    • Can sustain much higher G forces, which means they have a much higher list of launch and propulsion options available
    • Most (excepting food) have a much higher tolerance for radiation and acceptable temperature ranges.
    • Don't really need to consume much of anything on their own - they tend to be inert, and need very little (or no) upkeep.

    Honestly, if we expect to get somewhere, we need to be throwing out these large blobs of food/fuel/equipment in minimal containment vessels, with cheap, slow propulsion systems (i.e. very low mass/thrust ratio). Scatter a dozen along the path to Mars, and a dozen in Mars orbit, launching stuff a year or more before the humans plan to go. Then just build a SMALL crew vessel, with just enough storage space to get it between pit stops along the way, but with kick-ass engines.

    Manned vessels are expensive. Make them just big enough for the humans. Put the consumables in the space equivalent of a refrigerator, and let the human vessel dock with the frig every week or so to pick up supplies.

    ObCarAnalogy: build a race car and make frequent pit stops. Don't build a Semi with sleeper cab, 1,000L gas tanks, and a double trailer filled with food.

    -Erik

  • Would they be Self Serve 'Gas' Station or would it include full service?

  • Did any of the manned missions to the moon require refueling during flight?
    Why would we need a refueling station for moon trips now?
    • Did any of the manned missions to the moon require refueling during flight?
      Why would we need a refueling station for moon trips now?

      To move larger payloads to the moon?

      Saturn V was barely up to putting three men and a lander into a earth-moon orbit. If we want to lift something larger than that, we might want to use a dozen Saturn V (or equivalent vehicles) to boost 1000+ tons of fuel to earth orbit, then use one more to put a 200 or so ton spacecraft into Earth orbit, refuel, and off we go to the moon..

    • by Nyeerrmm (940927)

      Because Apollo depending on funding that isn't likely to happen now. Once the geopolitical goals were achieved, that money could be better spent other places.

      If we want a sustainable program for human expansion into space, things like this will be necessary.

  • Make a modular system that includes both a "unit" of fuel and the engine. Strap as many modules on the back of a crew/payload compartment as you need to accomplish the delta-Vs for the mission. Depending on mission, set up the used modules to burn up the atmosphere/hit the moon/end up some place where they don't become problematic space junk (i.e., don't quite use all of the fuel). Crew/payload compartment stays in orbit and gets re-used. Hire commercial space travel company to get people or equipment t

  • http://en.wikipedia.org/wiki/Interstellar_travel

    ... thus, the money is better spent on other space technology.

    http://en.wikipedia.org/wiki/Faster_than_light

  • Over the past decades there have been lots of papers about fuel, transfer of fuel, fuel needed, etc. I'd like to see a large scale demo of fuel transfer. Not some little demo on ISS but something of "man size" magnitude. It looks like this is a good project, I always wanted to try it myself but I just never had enough money.

    First objective is launch both at (or close to) same time, and get them to dock. Second, demonstrate transfer of fuel. They do it here on earth but doing it on large scale in space? P

  • by fritsd (924429) on Tuesday April 26, 2011 @02:37PM (#35944972) Journal
    Why not Argon instead of Hydrogen and Oxygen?

    Seriously, Hydrogen and Oxygen refueling sounds like they want to push the resulting water molecules out the back of the rocket with a standard rocket-fuel-burning momentum.

    But what happened to that Colombian company's idea of the VASIMR [wikipedia.org] drive; they were ready to test one out in space, on the ISS, but there are only 2 shuttle missions left and I haven't heard of a mission carrying that drive.

    Basically it would work like a giant microwave that accelerates Argon atoms to much higher speeds than a normal rocket, more like a Xenon ion drive, but cheaper.

    Can anyone comment as to whether this idea was shelved and why? Does it have problems, does it not work? Or is it because of politics

    Argon is a bit uncommon but hardly as rare as Xenon.
    • by Nyeerrmm (940927)

      VASIMR is still in development (and its being developed by an American company, Ad Astra, which was founded by an American astronaut of Costa Rican origin). I believe there is a demo going to the ISS in 2014 for station-keeping.

      The reason to look at doing this with traditional chemical rockets is that its the hardest case (so transferring the techniques to something inert like xenon or argon would be straightforward), and it also doesn't make the entire effort dependent on VASIMR being proven. It's been t

  • by Opyros (1153335) on Tuesday April 26, 2011 @04:13PM (#35946348) Journal
    This is actually one of the oldest ideas in space flight theory; the very concept of a space station arose out of it. As Arthur C. Clarke wrote in Interplanetary Flight (1950):

    From the conception of spaceships circling a planet for reconnaissance or refuelling, it was a natural step to consider the possibility of permanent orbital structures—"space stations"—and although this subject is perhaps subsidiary to the main theme of astronautics, it opens up so many important and stimulating prospects that it merits careful study. The idea of space stations was originated, like a good many other things, by Oberth, but was developed in great detail by two Austrian engineers, Captain Potocnik and Count von Pirquet. As first conceived, the space station was regarded largely as a refuelling depot for spaceships on their way to the planets, but it was soon realized that it would perform many other valuable functions.

"Consistency requires you to be as ignorant today as you were a year ago." -- Bernard Berenson

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