For the first time in almost half a century, scientists are going to get their hands on the rocks of the new moon.
The Chinese space agency’s Chang’e-5 spacecraft, which landed on the moon around 10:15 a.m. EST on December 1, will take the lunar soil from a region never visited before and bring it back to Earth a few weeks later. Those samples could provide details about an era of lunar history that had not touched previous moon missions.
“We’ve been talking since the Apollo era about coming back and collecting more samples from a different region,” says planetary scientist Jessica Barnes of the University of Arizona at Tucson, who works with lunar samples from American and Soviet missions. 1960 and 1970. "It's finally happening."
Chang-e-5, the last of a series of missions called the Chinese Moon Goddess (SN: 11/11/18), took off from the launch site of the National Space Administration of China in the South China Sea on 23 November and landed on volcanic plains in the northwestern region on the near side of the moon.
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The terrifier, equipped with a spoon and a drill bit, will collect about two kilograms of earth and small rocks, possibly from depths about two meters below the moon's surface, says Long Xiao, the planetary scientist at China Geosciences University in Wuhan.
The ship has to run fast. Without an internal heating mechanism, it has no defenses against the extremely cold lunar night, which can reach -170 ° C. The entire mission has to fit within a lunar day, about 14 days on Earth.
After the lander collects the sample, a small rocket will bring the lander and sample to the orbiter as early as December 3, although the Chinese space agency has not released the official calendar.
Once in orbit, the moon's material will be packaged in a return capsule and sent back to Earth. The capsule is scheduled to land in the Inner Mongolia region on December 17th.
The last time new lunar samples were sent to Earth was in 1976, for the purpose of the Soviet Union's Luna program. Between those missions and NASA’s Apollo missions, Earth scientists have about 380 kilograms of lunar material to study (SN: 7/15/19). “Maybe for a long time people thought, it was there, done this when it comes to the moon,” Barnes says.
Two pounds of new stuff may not sound like much next to what’s already on hand. But Chang’e-5 is returning samples from a completely unexplored region. The landing site is in the Mons Rümker region, in the northwestern region of the moon. Like the Apollo and Luna landing sites, Rümker is flat. “Engineering consideration comes first, be sure,” Xiao says.
All Apollo and Luna missions have visited ancient volcanic plains, where the rocks are between 3,000 and 4,000 million years old. Rümker volcanic rocks are much younger, between 1.3 and 1.4 billion years old. In the 1960s, scientists did not think the moon would remain volcanically active so late. More recent studies of the lunar orbit and telescopes have suggested a more complicated volcanic past.
“With these new samples, we potentially add another point in our geological history of the moon,” Barnes says. "Will we have an idea of what volcanic history was like on the moon a billion years ago? This is something we don't have access to in the returned samples we already have."
The Rümker region is also rich in potassium, rare earth elements and phosphorus, often called KREEP elements. These elements were some of the last to crystallize from the magma ocean that covered the new moon and may help reveal details of how that process happened. It’s an “exotic flavor” of material, Barnes says. "It's a very different area, geochemically, from the rest of the moon."
One of the biggest challenges for the mission will be drilling that material. The exercise cannot change direction once deployed, so you should try to traverse anything underneath. If the drill bit hits a large rock, it could fail. So the Chang’e-5 team expects a fine, loose solo, Long says.
Once the sample is back on Earth, it will be stored and cataloged at a curatorial center in Beijing. It will then be distributed for scientists to investigate.
“You can’t breathe easy on these kinds of missions until the samples are back and safe at the conservation site where they will be held,” says Barnes.
The Chinese space agency plans to share samples with international scientists. A 2011 Congressional rule makes it difficult for American scientists to collaborate directly with China, so it’s unclear who will work with the rocks. But the discoveries that the new samples will allow go beyond international borders.
“It doesn’t matter who does it,” Barnes says. "The whole world should be behind this mission and this effort. It's a piece of history. "