China's Chang'e 4 performed a historic first last week, with a soft landing on the farside of the Moon.
China completed a first in lunar exploration on Thursday, January 3rd, as its spacecraft Chang'e 4 (named after the Moon goddess in Chinese lore) landed on the lunar farside.
The spacecraft touched down at lunar longitude 177.6°E, latitude 45.5°S in Von Kármán crater at 2:26 Universal Time (UT), as per China's University of Geosciences at Wuhan. The lander wasted no time getting straight to work, snapping images of the lunar terrain. The small Yutu 2 rover rolled down the ramp and started exploring Von Kármán crater on the same day at 14:22 UT.
Launched atop a Long March 3B rocket on December 7, 2018, from the Xichang Space Center in China, Chang'e 4 took several weeks to reach lunar orbit. As suspected by science writer Andrew Jones, who observes the Chinese space program (follow him on Twitter for the latest news), Chang'e 4 landed in the 112-mile- (180-km-) diameter Von Kármán crater in the South Pole Lunar Aitken Basin right around local lunar sunrise. This timing gives the solar-powered lander and Yutu rover roughly two weeks of illumination, before they both have to ride out their first long lunar night in late January. One of the first images returned at 2:26 UT showed one foot pad of the lander sinking slightly into the lunar dust, but stable.
Watch the whole landing (at 2.5 times normal speed) here:
Credit: CNSA / CLEP
With Yutu 2 successfully deployed, Chinese space officials have released video of the rover driving on the Moon and then using its wheels to turn in place. (The videos were posted on YouTube by The Planetary Society.)
Credit: CNSA / CLEP
Communicating with the Lunar Farside
The lunar farside stays perpetually turned away from Earth. Although it also displays a paucity of lunar maria and looks markedly different than the familiar nearside, no mission crewed or robotic has ever landed there. The problem is a lack of direct line-of-sight communication with the Earth. Chang'e 4 uses a dedicated relay, the Queqiao (Chinese for magpie bridge”) orbiter perched in a lissajous halo orbit around the L2 Lagrange point, 37,000 miles (60,000 kilometers) past the Moon, to communicate with Earth. (Note: though the far side doesn't face Earth, it's not necessarily turned away from the Sun — the term "dark side" is a misnomer.)
Queqiao also returned some new pictures of the Earth-Moon pair as seen from its distant vantage point recently:
Now, the mission will get down to business, examining its new home with a battery of scientific instruments. The larger South Pole-Aitken basin that Von Kármán crater is embedded within is thought to be a section of exposed lunar mantle. Sampling this region could reveal information about the formation and structure of the Moon. The lander also carries plant seeds, yeast and fruit flies in a tiny enclosed experiment, to see how they fare growing on the Moon. In addition, Chang'e 4 will carry out radio astronomy observations from the radio-quiet lunar farside. Thanks to the mission's open data policy, the data collected will be shared with scientists all over the world.
What's Next for China on the Moon
Chang'e 4 is a follow-on and virtual copy of the successful Chang'e 3 mission, which landed in the Mare Imbrium in December 2013. China's next stated goal in lunar exploration is a sample return mission. The heavier Chang'e 5 lander and sample return capsule should launch later in 2019. However, before it can take to the skies, it will need to await a return to flight for China's Long March 5 heavy-lift rocket, which suffered a first-stage failure on its second flight in mid-2017. China practiced key maneuvers for the future mission — including high-speed skip reentry on a lunar free-return orbit as well as capsule return — with Chang'e 5T1, which returned a test capsule to Inner Mongolia in 2014.
Congrats to China on an amazing first, with more exciting lunar science to come!
Editor's Note (January 15, 2019): This story was updated to add videos from the China National Space Administration of Chang'e 4's landing and Yutu 2 driving on the farside of the Moon.
Editor's Note (January 14, 2019): This story was updated to show that the student experiment capsule is carrying plant seeds, fruit flies, and yeast, according to the Chinese news agency Xinhua.