With all the talk about humans going to Mars, sometimes we forget about the Moon. Sure, it's been 45 years since humans last visited, but there are plenty of good reasons to revisit our nearest heavenly neighbor.
One of the biggest is that the Moon could be a handy stop-off point for wider travel through the solar system. Nasa is already planning a space station that'll orbit the Moon and act as a staging ground for the Mars missions of the early 2030s.
But exactly what that lunar depot might look like is still a little unclear. That's why the California Institute of Technology recently hosted the 2017 Caltech Space Challenge, asking students from around the world to propose designs for a lunar launch and supply station.
In an on The Conversation, some of those students outlined what they see as the best approach. They suggested creating several small robotic bases on the surface of the Moon that would mine ice, manufacture liquid rocket fuel from it, and transfer that to passing spacecraft. With just three different types of rovers and a few small robotic shuttles, deep space missions could be refuelled in lunar orbit.
The first rover would explore and find ice-bearing locations. The second would build a launchpad there, as well as roadways, while a third collects the ice and delivers it to storage tanks and the processing plants that split it into hydrogen and oxygen using solar power. Finally, lunar supply shuttles would transfer that fuel into space.
The best place for this interplanetary petrol station would be the 'Lagrangian point' in between the Earth and the Moon. That's the scientific term for the place where the Earth and Moon's gravitational forces are equally strong, cancelling each other out. It's stable, making it a perfect pit stop.
The biggest benefit of this approach is that rockets bound for Mars wouldn't need to carry all their heavy fuel with them when they launch from the Earth's surface. That means more scientific and colonisation can be carried instead, tripling the possible payload they can carry with them.
"By helping us escape both Earth’s gravity and dependence on its resources, a lunar gas station could be the first small step toward the giant leap into making humanity an interplanetary civilization," wrote the students.