We now know where on the moon NASA astronauts will set foot after more than 50 years' absence.
The agency announced 13 potential landing regions for its Artemis 3 mission during a news conference held on Friday (Aug. 19). All the candidates are clustered near the south pole of the moon, an area of key scientific and exploration interest alike.
"They're of value to the scientific community and the technology community," Mark Kirasich, deputy associate administrator for the Artemis Campaign Development Division at NASA, said during the news conference. "People want and need to do things there."
"We can do exciting science at all of them," said Sarah Noble, Artemis lunar science lead for NASA's Planetary Science Division. "Many of these are places that the science community has been talking about for years."
The selected regions are: Faustini Rim A, Peak Near Shackleton, Connecting Ridge, Connecting Ridge Extension, two regions on the rim of de Gerlache Crater, de Gerlache-Kocher Massif, Haworth, Malapert Massif, Leibnitz Beta Plateau, two regions on the rim of Nobile Crater and Amundsen Rim.
The agency has identified and will evaluate more than 10 specific landing sites within each region, all of which are within six degrees of latitude of the south pole of the moon.
The constraints NASA has focused on to date have been strictly logistical, including how the site is lit, how easily a team of astronauts can communicate with Earth from the site, and the terrain. And NASA isn't building the vehicle that will ferry astronauts from lunar orbit to the surface, SpaceX's Starship, so the discussions have been held with the company as well as government personnel.
"This will be the first time we will land a human lander at the south pole, it will be the first landing of the Starship, so we have to pay close attention to the engineering and safety constraints of the mission and the vehicle," Kirasich said.
Moreover, site selection is complicated because NASA can't simply choose a site and move on: None of the 13 regions are constantly accessible, so the mission's launch date will determine where the astronauts can touch down.
"We will have to have, likely even for a given launch date perhaps, one or two sites, but we will have a collection of sites that we can use along a launch period," Kirasich said. "Exactly how many, we don't know yet; we have a lot to learn between now and then."
But NASA won't be relying on any scouts for additional information. The agency's venerable Lunar Reconnaissance Orbiter (LRO) has already provided the data that mission personnel need, according to Jacob Bleacher, chief exploration scientist at NASA. In fact, he said that at this point in LRO's mission, the spacecraft is in an orbit from which it can't observe these regions at all.
"But part of what went into some of our considerations for sites was the basis of availability of data," Bleacher said. "We can't target these locations again with the Lunar Reconnaissance Orbiter, but we have targeted them specifically in the past."
Whichever site Artemis 3 astronauts explore, their experience will be very different from that of the 12 men who have walked on the moon to date.
"This is a new part of the moon, it's a place that we've never explored," Noble said. "All six Apollo sites were in sort of the central part of the near side, and now we're going someplace completely different, with different and ancient geologic terrains."
And the south pole is a tantalizing destination because orbital observations show that frozen water is locked beneath the lunar surface in the stark cold of what scientists refer to as permanently shadowed regions.
Scientists hope that studying water and other "volatile" compounds that easily evaporate away will teach them about the moon's history and relationship with Earth. Meanwhile, the exploration-minded are interested in the ice because they hope it can support future humans on the moon or be made into rocket fuel.
Today's announcement comes just over a week before the targeted launch of Artemis 1, an uncrewed test flight for NASA's lunar exploration program. That mission's rocket stack is now on the launch pad at NASA's Kennedy Space Center in Florida, counting down to liftoff on Aug. 29.
Artemis 1 is meant to test the two key systems the moon exploration program will rely on: the Space Launch System (SLS) megarocket and the Orion crew capsule. If all goes well, NASA will send astronauts to lunar orbit on Artemis 2, targeting launch in 2024, before the new moon landing, which could occur in 2025 or 2026 if all goes well.
"I feel like we're on a roller coaster that's about to pass the top of the largest hill," Bleacher said. "Buckle up, everyone, we're going on a ride to the moon here."