Lunar-landing
missions are back in vogue. After decades with almost no traffic to the moon, space
agencies clamored to send spacecraft to Earth’s nearest neighbor in 2019. While
the China National Space Administration parked the first spacecraft on the
lunar farside, other missions met less-satisfying ends. Two probes, flown by
the Israeli nonprofit SpaceIL and the Indian Space Research Organization,
crash-landed on the moon and haven’t been heard from since.

The moonshot renaissance is just getting started. China
plans to launch another lunar lander next year. The European Space Agency is
working on a series of moon landing missions with the Russian space agency
Roscosmos. And NASA hopes to use several trips to the moon in the 2020s as a
springboard for sending astronauts to Mars.

And “it’s not just a government superpower that can achieve
a lunar landing now,” says planetary scientist Philip Metzger of the University
of Central Florida in Orlando. Advances in navigation technology and robotics,
along with lowered launch costs, have private companies planning their own
trips.

Scientists are still learning from data collected by the Apollo missions (SN: 7/6/19 & 7/20/19, p. 26), and satellites have watched the moon from afar in the decades since. But orbital observations can’t compete with closeup views, says Steven Clarke, deputy associate administrator for exploration at NASA’s Science Mission Directorate in Washington, D.C. To help solve mysteries about the solar system’s history and prepare for future human visits to the moon, “you really need to go actually touch the samples that you want to examine,” Clarke says.

When the Chinese Chang’e-4 lander touched down on the moon’s farside in January, it became the second spacecraft — after the Chang’e-3 mission in 2013 — to land on the moon since the Soviet Union’s Luna 24 mission in 1976 (SN Online: 1/3/19). Already, Chang’e-4’s rover has discovered what appear to be bits of the lunar mantle mixed into the surface soil (SN: 6/8/19, p. 7). If truly from the mantle, those minerals might help hammer out how the once-molten moon cooled and hardened. Chang’e-5, expected to launch in 2020 and return moon rocks to Earth for the first time in over 40 years, could offer further insight into moon formation (SN: 11/24/18, p. 14).

Yutu-2 rover
In 2019, China’s Chang’e-4 spacecraft reached the moon’s farside and delivered the Yutu-2 rover (shown). The rover has discovered minerals on the lunar surface that may come from the moon’s mantle.China National Space Administration

The Israeli and Indian mission crashes were harsh reminders of how much can go wrong. In April, SpaceIL lost touch with its lunar lander, Beresheet, mere minutes before the spacecraft was supposed to land (SN Online: 4/11/19). Likewise, India lost contact with its Vikram lander right before the probe crashed on the lunar surface in September (SN Online: 9/20/19). Vikram was supposed to get closer than any other rover to the moon’s south pole, where orbiters have detected water ice (SN Online: 7/22/19).

“Getting data on the ice [would] be game-changing,” Metzger
says. There’s a good chance that much of this ice came to the moon on comets,
and Earth could have gotten its water and other ingredients for life in a
similar way. Studying the lunar ice could offer clues about when it arrived and
where in the solar system it originated, he says.

Water from this ice might help sustain future human visitors
on the moon, Clarke adds. To take inventory of that potential resource, NASA
plans to send a rover called VIPER to the lunar south pole in 2022. China also
has a lander bound for the south pole in 2023. The Israeli and Indian groups
have not announced plans for new lunar landing attempts.

By sending spacecraft to never-before-visited locales, NASA and other lunar-landing hopefuls can help create a more global profile of the moon, Metzger says. “The area of the moon is equivalent to an entire continent on the Earth,” he notes. Despite all we’ve learned, “we’ve barely touched the surface of the moon.”