Heading to Mars? Stop by the moon to refuel

In the future, the most cost efficient way to get to Mars might be to not go to Mars directly at all. By carrying just enough fuel to reach the moon and then refuel to get to Mars, the entire launch system's mass could be reduced by as much as 68 percent, a saving that would have a ripple effect down the line. This almost unintuitive proposal is exactly one that professor Olivier de Weck and researchers from MIT are making to make future Martian trips more feasible.

Even de Weck himself admits that the idea is unorthodox, given the two strategies currently in use by NASA and other space programs. The first, nicknamed "carry-along", dictates that the crew carries everything that's needed for the mission, both vehicles and resources. It's like putting all your eggs in one basket. Another approach is the "resupply" strategy, where a base, like the International Space Station for example, is routinely resupplied with resources.

The MIT research paper propose something along the middle ground. A mission going to Mars would only carry enough fuel to jettison it into space and get into orbit around Earth. Once that's done, stations on the moon will release refueling tanks that the rockets can then get to restock on their supply, after which they can continue the journey to the red planet. A reduction of more than half in mass has significant implications, considering it is one of the biggest factors in determining the cost of a launch.

As for the fuel themselves, those can potentially be made on the moon itself. Or on other locations where such stations will be installed. Both the moon and Mars have some resources that have the potential to be transformed into fuel. Nobody has just done it yet.

The refueling stopover is based on mathematical models built by MIT postdoc Takuto Ishimatsu, whose work the Ph.D. thesis is the foundation of the proposal. His model also includes the possibility of developing such stations beyond the moon, for future explorations farther than Mars. That said, the model does preclude many things, some of which are not currently available. It requires, for example, that we have already developed such technologies and equipment that can mine the moon, Mars, and other space resources to turn them into rocket fuel, something that a mathematical model alone can't produce.