In 2010, during a speech at the Kennedy Space Center in Florida, President Barack Obama directed NASA away from its primary target, the moon, to focus its human exploration missions beyond the lunar surface to an asteroid and Mars.
“I just have to say pretty bluntly here: We’ve been there before,” he said. “There’s a lot more of space to explore, and a lot more to learn when we do.”
The United States has since reversed course, with the moon once again the centerpiece of NASA’s exploration goals. Under its Artemis program — born during President Donald Trump’s tenure and embraced by the Biden administration — NASA has real momentum and bipartisan political support for one of the most ambitious human space flight efforts in decades. It began with the launch of its massive SLS moon rocket and Orion spacecraft on Nov. 16, a mission without any people on board. The Artemis I mission will be followed by subsequent flights with astronauts — first orbiting the moon and then eventually landing on the surface.
But despite the progress, the concern raised by Obama still hovers over the space program: We’ve been there, done that. Why return to the moon?
The answer, said Thomas Zurbuchen, the recently retired head of NASA’s science mission directorate, begins with the presence of water.
“It’s important to recognize that we’re going back to a moon that’s really different than the moon we left when we took off during Apollo,” Zurbuchen said in an interview. “It was a moon that was dry. … Our understanding of the moon is massively different.”
As a result, NASA has made establishing an enduring presence on the moon central to its future space ambitions. It will allow the program to practice how to live in space sustainably. It will allow scientists to tap into the moon’s considerable scientific value to learn more about how Earth was formed. And perhaps, it would also serve as a steppingstone to Mars and other deep-space destinations years in the future.
Water is not only key to sustaining human life, but its component parts — hydrogen and oxygen — can be used as rocket propellant, making the moon a gas station in space. That could be critical for long-duration missions, allowing spacecraft to refuel on the moon instead of lugging all the fuel from Earth. And since the moon’s gravity is one-sixth of Earth’s, it is a relatively easy springboard to other points of the solar system.
The moon also has a story to tell — both about the formation of the solar system and how Earth came to be. Without an atmosphere, it’s a time capsule. The Apollo astronauts’ footsteps remain intact, undisturbed by weather or wind, as do the scars of billions of years worth of bombardment of asteroids and comets that were part of the early formation of the solar system.
“It’s less about finding life itself, but it certainly is about the journey to life,” Zurbuchen said. “The moon can tell us a lot about our own solar system, the violent processes that created our planets and scarred their surfaces. … Part of our history is right there, hanging out over our heads, and it is eminently possible to travel there.”
Getting to the moon is extremely difficult. Living there is even more so, and it’s not something NASA has a lot of experience with. The last of the Apollo crews, Apollo 17, spent the most time on the moon — just over three days. And that was in 1972.
The evolution from the short-term probes to long-term lunar homesteading — from exploration to expansion — will require a serious commitment of resources and new technologies.
Which is why NASA is looking to build a nuclear reactor on the moon.
It’s one of several initiatives NASA has begun under its Artemis program, designed to help astronauts stay for extended periods when they’ll need power, transportation and the ability to use the moon’s resources. They would need habitats, rovers and mining equipment, along with tools to extract the water and mold the lunar regolith (also known as moon dirt) into bricks for habitats.
The effort is still very much in its nascent stages, and the funding NASA would need for the long term has not materialized in full. A sustainable presence, despite the rosy predictions coming from the top echelons of the agency, is still years away, and the technical challenges are immense.