Science & Technology

Why is NASA Going Back to the Moon Before Heading to Mars?

NASA's new space plan sounds a bit like a time warp. The agency wants to bring humans back to the moon, a place that twelve people already walked upon between 1969 and 1972. Why are we going back again nearly 50 years later? As NASA's new administrator Jim Bridenstine said in a major speech in Washington, D.C. last week, the moon will help us prepare for Mars. "We are doing both the moon and Mars in tandem, and the missions are supportive of each other," he said at the annual Humans to Mars Summit.

The Moon Is a Different Place to Us Now

Fifty years is a really long time, and in those five decades we've discovered the moon is not the dry, barren, nearly unchanging place we thought it was. The biggest discovery in recent decades? Finding water. Yes, there does appear to be water ice in permanently shadowed craters on the moon's surface. This means that future explorers may not need to bring all their water with them. We could build a moon colony near the ice and, in theory, extract the water for drinking, showering, or cleaning.

There are other weird features worth exploring as well. Ancient underground lava tubes could serve as great spots for humans to take shelter against the radiation bathing the moon's surface. The moon has bizarre levitating dust that, through electrostatic charges, dances on the surface during lunar sunrises and sunsets. And we've also come to appreciate the moon as a time capsule. All those craters and divots on the surface are scars of our solar system's history, scars that Earth would have too if they weren't erased by wind, water, and earthquakes. So by studying the moon, we can actually learn a little bit about how Earth formed. Talk about a cosmic origin story.

We Can Prepare for Mars

The moon is relatively close to us; the Apollo astronauts were able to reach it only two days after they lifted off from Earth. That's really convenient if an emergency occurs. When the Apollo 13 spacecraft suffered an oxygen tank explosion in 1970 while the astronauts were still going to the moon, all NASA had to do was have the astronauts loop around the moon and zip back to Earth for a safe landing. So the moon serves as a handy testbed for exploring deep space — with the safety net of knowing that if something goes terribly wrong, the astronauts can still get home relatively quickly.

We can also test out technologies on the lunar surface that would be useful on Mars. How do we build a habitat where astronauts can stay safe and productive for months at a time? What spacesuits can we use again and again, even with corrosive lunar dust eating away at the protective layers of the suit? Astronauts can test all sorts of things on the lunar surface, from rovers to mining tools to science techniques.

Mars and the moon aren't perfect twins, of course, but any practice for living in space will be useful for the Red Planet. Mars will present even more challenges to astronauts because it's further away and it's a planet with dust storms and other weather. But it might be easier in some senses, too. Mars has a day that's close to our 24-hour day. And as humans, we may feel psychologically better looking around at a ruddy, wind-swept landscape that resembles some desert zones on Earth.

So When Are We Going?

Well, that's the tricky bit. Before the announcement in December, NASA's long-term goal was a mission to Mars sometime in the 2030s. As you can imagine, that's an expensive undertaking; NASA is building a rocket (called the Space Launch System) and a spacecraft (called Orion) that's supposed to bring astronauts out there in the coming decades. But the moon is a costly detour. Some critics worry that if NASA focuses on the moon, a human Mars mission will be pushed out by a few years or decades. An optimist might think we'd get to the moon in the 2020s, but that depends on money.

NASA is already reconfiguring its annual budget for the new plan. When the agency made its 2019 proposal in February, the budget included cuts to education, a high-profile telescope called WFIRST, and even (ultimately) the International Space Station (ISS). The budget calls for the agency to stop operating the ISS in 2025. Presumably, that money could be used for moon and Mars missions, but it's a bit early to know what will happen next.

That said, it would be neat to go back to the moon while the Apollo astronauts are still alive to enjoy it. Apollo 16's John Young died in January, leaving only five surviving astronauts of the 12 who walked on the moon. All of those people are between 82 and 87 years old today. As this comic from xkcd shows, at best we have until 2035 to send someone to the moon before the rest of the moonwalkers die.

"The universe is probably littered with the one-planet graves of cultures which made the sensible economic decision that there's no good reason to go into space — each discovered, studied and remembered by those who made the irrational decision," reads the mouse-over caption to the comic. So let's hope that wherever we choose to go, we still choose to explore — to learn more about the Earth and the planets surrounding us.

For a hilarious take on the strange details involved in a Mars mission, check out "Packing for Mars: The Curious Science of Life in the Void" by Mary Roach. We handpick reading recommendations we think you may like. If you choose to make a purchase, Curiosity will get a share of the sale.

Written by Elizabeth Howell May 24, 2018

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