The payload of a manned mission to Mars could be reduced by more than two-thirds if the crew took a detour to the moon to refuel their spacecraft, researchers from the Massachusetts Institute of Technology (MIT) reported this week in the Journal of Spacecraft and Rockets.
According to MIT aeronautics and astronautics professor Olivier de Weck, a vehicle carrying astronauts could make a detour to the lunar surface, where it could use fuel that was created from soil and water ice mined from craters there. By doing so, they could reduce the mass of the spacecraft by as much as 68 percent, based on the study authors’ calculations.
The researchers created a model to determine the best route for a trip to the Red Planet, finding that the most mass-efficient path involved launching from the ground with just enough propellant to reach orbit around the Earth. Then a fuel-producing facility on the moon would launch tankers of fuel into space, placing them into gravitational orbit to be picked up by the Mars crew.
“This is completely against the established common wisdom of how to go to Mars, which is a straight shot to Mars, carry everything with you,” said de Weck. “The idea of taking a detour into the lunar system… it’s very unintuitive. But from an optimal network and big-picture view, this could be very affordable… because you don’t have to ship everything from Earth.”
‘In-situ resource utilization’ would significantly reduce launch mass
Historically, space travel missions have used two different strategies to ensure that the crew had access to an adequate supply of resources. One is the carry-along approach in which the supplies and fuel needed by the crew traveled with them at all times, and the other is a resupply approach in which resources are replenished at regular intervals (the ISS, for example).
This may not be a sustainable approach as humanity ventures further away from Earth, de Weck and her colleagues wrote. They propose that Mars missions, as well as voyages to other far off destinations, require new strategies based on “in-situ resource utilization”. This concept centers around the production and collection of fuel and provisions en route to a destination.
During the in-situ resource utilization approach, materials ordinarily carried into space from Earth would be replaced by those produced in space, MIT explained. For instance, water ice, (which has been found on Mars and the moon), could theoretically be mined and converted into fuel. In their study, the researchers created a variety of different possible routes to Mars to determine if taking a series of pit stops en route to Mars would be more efficient than direct travel.
They found that the lunar-based refueling stop minimized mass that was launched from Earth, but it also assumed a future scenario in which propellant could be processed on and transported from the moon to a point in orbit, and that fuel depots can be established at gravitationally-bound locations in space (also known as Lagrange points). Nonetheless, the team said that their work emphasizes the importance of creating a resource-producing infrastructure in space.
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Feature Image: Christine Daniloff/MIT
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