Mars' Mount Sharp, taken by the Mars Curiosity rover in January 2018. Image: NASA/JPL-Caltech/MSSS
The Trump administration has set its near-term sights on returning humans to the moon and, by the 2030s, to orbit or land on Mars.
Between the lines: NASA funding is key to human exploration of Mars, and some worry a mission to the moon could divert resources needed to reach the Red Planet. The agency is looking for the commercial space industry to take on more low-Earth orbit and lunar activities. When it comes to NASA resources for an eventual Mars mission, the moon is “the elephant in the room,” Artemis Westenberg, president of Explore Mars, said at the Humans to Mars Summit this week.
“We’re doing both the moon and Mars, in tandem, and the missions are supportive of each other.”— Jim Bridenstine, NASA administrator, at Humans to Mars Summit, Wednesday
Establishing infrastructure at a "gateway" in cislunar space — the region between Earth and the moon — has long been proposed as a way to get to Mars.
- Boeing's Peter McGrath said the region could be used to develop propulsion systems that can take humans further out to Mars. It could also help us study human factors related to Mars exploration, like the psychological impact of living far from home for longer durations or the effects of radiation on human health.
- "In cislunar space, you can prove you're Earth-independent. Right now we're not — the ISS [International Space Station] is not," said Westenberg.
The sticking point is the renewed focus on landing humans on the moon. Bridenstine said that will help the development of precision landing systems, habitats on the surface or in orbit, surface mobility technologies, and methane engines for Mars.
Some moon-related technologies could be relevant to Mars exploration, but others may not be, raising the question of how much should be invested in developing those technologies.
- Compact reactors to generate nuclear power lend themselves to early testing on the moon, according to Aerojet Rocketdyne's Joe Cassady. "That would be useful for the people who want to mine the moon," he said, adding it would also inform the technology's use for Mars exploration.
- Surface mobility (think: rovers and spacesuits): Some aspects of spacesuit design could be transferable between the moon and Mars, but moon dust and the Mars variety differ. "We could do a lot of stuff to make a perfect rover for the moon, but it may not transfer completely to Mars," said Cassady.
- Demonstrating surface systems for Mars on the moon would "take a lot of time and money" and while experimenting with mining technology is "probably a good thing to do on the moon...you can do a lot of that robotically," said McGrath.
"The big challenge is going to be not getting diverted into things that are solely useful for resource development on the moon," said Cassady. "I really don’t see it as an either or. I think we can make this work."
One key difference: The moon doesn't have an atmosphere — but Mars does, so a landing on Mars can take advantage of drag and is better practiced in high-Earth altitudes (above 100,000 feet).
“[The moon] is not exclusively the stepping stone,” says Eric Stallmer from the Commercial Spaceflight Federation, whose members include SpaceX (which is developing a rocket for getting people to Mars). “If there are commercial vehicles and opportunities available for Mars, it could bypass the moon.”