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NASA Looking To Build 'Gas' Stations In Space
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."
Aww man I'd hate to smell the mens room in that place.
"(I) have this unfortunate condition that causes me not to believe a single thing any politician says when a mic's on.
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.
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.
Great warrior...hrmph! Wars not make one great.
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.
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.
I piss off bigots.
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 quickly. You still have to launch the fuel, but once it is in LEO, any vehicle can use it. Combine that with a system which allows space planes to connect to an external tank which never has to return to earth (rent-a-booster system) and you create a flexible system which optimizes the incredible cost of moving around in space. Both locally and interplanetary.
Rather than
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.
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.
File under 'M' for 'Manic ranting'
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.
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 vessels from Earth (food, fuel, etc).
Eclectic beats from Leeds, UK
handmadehands.co.uk
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 assembly.
[*: Assuming it's a space exploration agency, and not a glorified jobs program.]
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:
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
There are always four sides to every story: your side, their side, the truth, and what really happened.
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.
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).
File under 'M' for 'Manic ranting'
Before anyone takes anything an AC says seriously: the Van Allen belts extend up to about 50,000km, while the moon is over 350,000km away. And we've sent humans to the moon.
Those who fail to understand communication protocols, are doomed to repeat them over port 80.
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.
Two of my imaginary friends reproduced once
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.
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 for station-keeping at L2. There's more details in this ULA publication on depot architectures:
http://www.ulalaunch.com/site/docs/publications/AffordableExplorationArchitecture2009.pdf
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? Pros and cons of cryogenic fuels vs. hypergolic (i.e. hydrazine) fuels.
Then third objective is send that spacecraft beyond LEO, not GEO but a huge distance to show means of actuallly going somewhere. Yes, it will take fuel to get the fuel to orbit but will this increase BEO capability beyond Voyager/Cassini size spacecraft? Will it enable faster Mars transit time? Will it violate the laws of physics (i.e. Rocket Equation)? What will probably shoot this thing down is the money, which is all what we scream about these days.
They are looking for $200M to demo (why cryogenic only? maybe start with this and work on others later). If this shows promise then maybe we'll finally get somewhere.
I say forget trying a HLV, that is a political non-starter. Medium launchers and fuel transfer is needed if want humans beyond earth orbit. Forget trying to build a 130t launcher, the money will never be allocated and if it does it may be yanked next year or soon after. Look how much bitching over SLS, by the time they agree we will all be dead of old age!
This method was one of the modes for Apollo but it was a significant challenge to be sure both rockets will launch (if one can't make it, then the second one is useless). If delay in one, you don't want to be hanging out in LEO for an unknown amount of time, probably can but that will lead to other issues to deal with. They agreed with John Houbolt and went LOR.
mfwright@batnet.com
Good one! The moon has water.
More over Mars has a CO2 atmosphere. Also on Mars is Magnesium that will burn in a CO2 atmosphere. You move CO2 and processed Metals that will burn in the presence of CO2 in to orbit. And you have a refueling station.
Given robots go first and make fuel 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. Getting the mass of the fuel, on site and all set up, before we commit people to the flight. This is simply good economy, and safety.
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.
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 money to launch fuel and payloads on 320 Falcon Heavies (16,960mt total payload). This of course ignores the greater economics of scale that could be obtained if you were launching a rocket that many times.
In an optimistic scenario, the Ares V would launch once or twice per year. If you assumed that the Ares V launched twice per year and was completely free to operate (which is false, as it actually would've cost billions more to operate), it would take 45 years before the Ares V would have launched more payload than you could've launched spending the same money on Falcon Heavies.
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 probe with its Ion engine. The downside: it took 13 months (it only took the Apollo astronauts a couple days) and used a series of really strange, 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 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.
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 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.
To be, or not to be: isn't that quite logical, Slashdot Beta?
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.
"Windows is like the faint smell of piss in a subway: it's there, and there's nothing you can do about it." - Charlie Br
They thought about it, and it turned out that ion engines and fission reactors have horrible thrust/mass ratios which would mean trips would take a very long time, though they would use a lot less fuel like chemical rockets.
If you can increase an ion thruster's thrust by quite a lot, and downsize a fission reactor by quite a lot, we can talk again.
Screw this "gas station in space" concept, I want a refinery in space.
SPSS + particle accelerator = antimatter.
hell, a electrodynamic tether generator might be worth trying, too.
And it's probably going to be easier to store that antimatter up there in space to boot.
Then we can start going places fast(er).
the preceding comment is my own and in no way reflects the opinion of the Joint Chiefs of Staff
But what's the point of L2? You need a depot in Earth orbit to fuel up for the trans-lunar burn, and one in Lunar orbit to fuel up for the trans-earth burn. Why put the lunar depot at L2 as opposed to a lunar orbit?
I'm by no means an expert, but my understanding is that there's a few different advantages L2 has over LLO:
* Lower delta-V to reach it from LEO (3.43 km/s vs. 4.04 km/s), and -much- lower delta-V to go from there to Earth escape orbit (0.14 km/s vs. 1.4 km/s). This makes it much more practical for sending missions/probes to Mars, the outer planets, or just about anywhere else in the solar system.
* In that likely case that you're using hydrogen/oxygen propellant, boil-off is going to be your primary long-time storage concern. In LEO (and presumably lower orbit) you not only have to worry about shielding a depot from the Sun, but also have to worry about shielding the thermal emissions from a nearby constantly-moving terrestrial body. If you're in EML2, all you need is a sun shield to keep the temperature down.
* I suspect it's much more difficult to dock with a constantly-moving target in lunar orbit than with a more stationary target at a Lagrange point, both in terms of actual maneuvers and mission scheduling.
* There's substantial gravitational anomalies in the Moon, adding stationkeeping costs for maintaining a consistent lunar orbit.