NEW YORK – To claim we’ve already been to the moon is like spending a day each in Iowa, Arizona, Rhode Island and maybe western Pennsylvania and saying you’ve already been to Earth. There’s a lot more to see on the moon — including the whole far side, the half that’s perpetually turned away from us. That’s one reason for the excitement behind the Chinese-led mission Chang’e-4, which landed in this unexplored region earlier this month.
Images from lunar orbit show the geology there is strikingly different from the sites where Apollo astronauts explored. The craft landed in a vast depression called the South Pole-Aitken basin, which takes up a quarter of the lunar surface and appears to have formed early in the history of our solar system, said planetary geologist Seth Jacobson of Northwestern University. The rocks there could hold clues to how our own planet formed.
The prevailing theory about the moon’s origin is a dramatic one: Soon after a proto-Earth came together, it collided with another planet the size of Mars, coalescing into a bigger planet and the moon. Jacobson said the lander is in an area where rocks from beneath the moon’s crust may have been brought to the surface by ancient impacts. Both NASA and the China National Space Administration have proposed missions to go back to this area and collect samples.
Though tantalizing, the far side is tough to visit because there’s no way to communicate directly with a lander, he said. You need an orbiter to relay signals. One of the scariest parts of the Apollo 8 mission, he said, was the period when astronauts flew behind the moon and lost all contact with mission control.
But the radio darkness is a plus for some astrophysics quests, including the detection of subtle radio waves emanating from deep space — energy remnants of the early universe that would be drowned out on Earth. And so Chang’e-4 also carries a prototype for the kind of lunar radio telescope that might one day be built on a larger scale.
The U.S. is still the unquestioned leader in space exploration — the Chinese landing came just two days after an American probe’s spectacular flyby of an icy body 6.6 billion km away, called Ultima Thule, which qualifies as the most distant object ever reached by spacecraft. The same NASA craft, New Horizons, had a close encounter with Pluto in 2015. But the moon is a place astronauts might go, and so Chang’e-4 has spurred talk of a new space race.
The experts I spoke to were keen to send astronauts back to the moon, though preferably not as part of an unfriendly international competition. Planetary scientist Clive Neal of Notre Dame said that space races aren’t sustainable in the long term. The Apollo missions were world-changing but ended after just a few years. Now, informed by history, he said, we could go about a more collaborative program that would get astronauts to the moon and beyond.
While sending people to the moon might seem like a modest goal compared with a trip to Mars, learning to live on the moon would help scientists learn how to keep humans alive and healthy on longer journeys. There are known deposits of water ice on the moon, said Neal, and depending on its purity, these might supply a moon base with water or be separated into hydrogen and oxygen and used to fuel a Mars mission.
Humanity would get farther faster and would gather more scientific wisdom by international collaboration than by space racing, but Congress currently restricts NASA collaboration with the Chinese under what’s known as the Wolf amendment, introduced by Virginia congressman Frank Wolf. The rationale was prevention of espionage. There were concerns over Chinese hacking and a Chinese scientist who left a NASA facility with an unauthorized laptop. Time magazine reported that the laptop contained pornography and pirated movies but no national secrets.
Jacobson said it’s worth noting the symbolism of where the Chinese chose to land on the moon: the crater-within-a-crater named after Theodore von Karman, who was the head of the Jet Propulsion Laboratory and a mentor to a young Chinese researcher — Hsue-Shen Tsien — who became one of the world’s great rocket scientists. The two worked together before and during World War II, and Tsien is now recognized for making a major contribution to the U.S. space program.
But after the war, common enemies no longer sustained the alliance, and in the 1950s, during the communist scare, Tsien was interrogated, put under house arrest for five years and then deported. Upon release, he headed the Chinese nuclear weapons program, putting it on the fast track to nuclear weapons and long-range missiles.
Could sending the Chinese spacecraft to the Von Karman crater be an intentional gesture of reconciliation and hope for further cooperation? Perhaps it’s just a coincidence, but one that can serve as a reminder of the collaboration that gave birth to space travel in the first place.
Science writer Faye Flam is a Bloomberg Opinion columnist. She has written for The Economist, The New York Times, The Washington Post, Psychology Today, Science and other publications.