Space

MIT researchers propose gas stations in space

Fuel depots in space could help make future missions to the Moon more economical says an MIT team (Image: Christine Daniloff/MIT)
Fuel depots in space could help make future missions to the Moon more economical says an MIT team (Image: Christine Daniloff/MIT)

Getting into space is an expensive business where every little bit of extra weight, which includes the fuel powering the spacecraft, can add thousands of dollars to the cost of a mission. A team of researchers at MIT proposes establishing gas stations in space as a possible way to help cut the cost of future missions to the Moon.

Before you point out that establishing a "gas station" in space would require fuel to be hauled up to it in the first place, rendering such a concept moot, the MIT team points out that lunar missions carry a supply of "contingency propellant". This is essentially the equivalent of a can of extra gas thrown in the boot that can be pulled out in the case of an emergency.

Rather than just leaving this backup fuel on the Moon or burning it up on re-entry as is usually the case, the MIT team suggests spacecraft could drop it off at a depot positioned between Earth and the Moon on their way home.

This way, following missions could dock at the depot to pick up the fuel tank for use as its own contingency propellant before continuing on to the Moon. Then, on it's return journey, it could drop off the fuel again if it wasn't used. The team calls this a "steady-state" approach.

Additionally, the depot would be able to stockpile fuel from multiple missions that could be used to top up a lunar mission on its way to the Moon, thereby keeping the amount of fuel carried at launch to a minimum.

'Whatever rockets you use, you’d like to take full advantage of your lifting capacity," says Jeffrey Hoffman, a professor of the practice in MIT’s Department of Aeronautics and Astronautics. "Most of what we launch from the Earth is propellant. So whatever you can save, there’s that much more payload you can take with you."

The team says such an approach would be more cost-effective than other proposals that involve sending tankers to refill orbiting depots or building fuel-manufacturing stations on the Moon like those being pursued by the Shackleton Energy Company.

The fuel depots would be positioned at Lagrange points where they would maintain gravitational equilibrium, allowing them to keep the same relative position with respect to the Earth and Moon.

Hoffman says the ideal approach would involve astronauts or a robotic arm picking up a tank, but that siphoning furl from the depot to the spacecraft would also be doable. However, the siphoning approach would pose greater difficulty because the fuel would float in the gravity-free environment.

Both approaches would also require the depots to be maintained so they remained within the Lagrange point and to ensure the fuel was kept at temperatures cold enough that it didn't boil away. But if these challenges could be overcome, Hoffman says fuel depots in space could provide an efficient way to support future missions to the Moon.

"One of the problems with large space programs is, you invest a huge amount in building up the infrastructure, and then a program gets canceled," Hoffman says. "With depot architectures, you’re creating value which is robust against political uncertainty."

The depot architecture proposed by Hoffman and his students, Koki Ho, Katherine Gerhard, Austin Nicholas, and Alexander Buck, is outlined in the journal Acta Astronautica.

Source: MIT

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8 comments
Seanfobd
Surely the real requirement is a biofuel production station utilising the abundant sunlight available.
Glen Davis
What if; We somehow devise the method to create a fuel from the moon's surface to make "Connaco-hottest bran going" fuel stations from? As a carrier fuel station.... Fuel outpost's.... Prisons, so prisoners can mine for there crime... An entire economic area... In space. What if? Science fiction to science fact.
Pat Kelley
The solution varies, dependent on the mission: Lunar deposits of He3 have been the target for fusion-powered vehicles (if we can ever make fusion systems work); the Moon also appears to have plentiful supplies of water, which can be electrolyzed into hydrogen and oxygen; Mars now appears to have water, and combining that with the carbon dioxide in its atmosphere, we can create methane fuel. More exotic ideas would include tapping solar power and creating laser or maser "cannons" to send energy directly to spacecraft equipped with receiver surfaces so they can be accelerated with no fuel needed.
Jon A.
This is not even remotely a new idea.
NASA was talking about orbital fuel depots in the 1960's.
Stephen N Russell
Lost in Space TV show used this in 1 episode, Season 1 for Jupiter 2. Need prefab modules to assemble fuel stations & then to place in orbits for spacecraft to dock & drain off fuel into main tank alone. Use ISS to launch? Can be manned or unmanned depots?
JoejustJoe
Or you could stop wasting 90% of your fuel and just use JP Aerospace's system of achieving orbit and save billions of dollars.
christopher
Is there no end of people completely incapable of comprehending the speed of things in space?
Just to stop at this gas station, then re-accelerate, is going to use up more fuel than can be exchanged - and, in the process, is going to contribute an exhaust storm / minefield of particles for every future vehicle to collide with...
Slowburn
A LEO fuel depot could be workable scavenging fuel left in the tanks of launch vehicles and the station could also chop up the rest of the vehicle to make radiation shields, Whipple shields or even habitats reducing the mass that has to be orbited.
@ Seanfobd It take more than sunlight to make rocket fuel you have to add mass.