Humanity just planted its flag on the far side of the moon. China’s robotic Chang’e 4 mission touched down on the floor of the 115-mile-wide (186 kilometers) Von Kármán Crater Wednesday night (Jan. 2), pulling off the first-ever soft landing on the mysterious lunar far side.
Chang’e 4 will perform a variety of science work over the coming months, potentially helping scientists better understand the structure, formation and evolution of Earth’s natural satellite. But the symbolic pull of the mission will resonate more with the masses: The list of unexplored locales in our solar system just got a little shorter. [Watch: China’s Historic Landing on the Moon’s Far Side!]
The epic touchdown — which took place at 9:26 p.m. EST (0226 GMT and 10:26 a.m. Beijing time on Jan. 3), according to Chinese space officials — followed closely on the heels of two big NASA spaceflight milestones. On Dec. 31, the OSIRIS-REx spacecraft entered orbit around the near-Earth asteroid Bennu, and the New Horizons probe zoomed past the distant object Ultima Thule just after midnight on Jan. 1.
“Congratulations to China’s Chang’e 4 team for what appears to be a successful landing on the far side of the moon. This is a first for humanity and an impressive accomplishment!” NASA Administrator Jim Bridenstine said via Twitter Wednesday night, after word of the milestone began circulating on social media.
Congratulations to China’s Chang’e-4 team for what appears to be a successful landing on the far side of the Moon. This is a first for humanity and an impressive accomplishment! pic.twitter.com/JfcBVsjRC8
— Jim Bridenstine (@JimBridenstine) January 3, 2019
It takes the moon about the same amount of time to spin once on its axis as it does for the natural satellite to orbit the Earth: 27.3 days. Because of this “tidal locking,” we only ever see one face of the moon, which we call the near side. [China’s Chang’e 4 Moon Far Side Mission in Pictures]
This familiar face has welcomed many visitors over the years, both robotic and human; all six of NASA’s crewed Apollo missions to the lunar surface touched down on the near side. The far side is a much tougher target for surface exploration, because the moon’s rocky bulk would block direct communication with any landers or rovers there. (And don’t call it “the dark side”; the far side gets just as much sunlight as the near side.)
To deal with this issue, China launched a relay satellite called Queqiao in May 2018. Queqiao set up shop at the Earth-moon Lagrange point 2, a gravitationally stable spot beyond the moon from which the satellite can keep both Chang’e 4 and its home planet in sight.
The data flow through Queqiao will likely be extensive. Chang’e 4, which launched on Dec. 7 and entered lunar orbit 4.5 days later, boasts eight science instruments: four apiece on a stationary lander and a mobile rover.
The lander features the Landing Camera, the Terrain Camera, the …
By Mike Wall
Mike Wall’s book about the search for alien life, “Out There” (Grand Central Publishing, 2018; illustrated by Karl Tate), is out now. Follow him on Twitter @michaeldwall. Follow us @Spacedotcom or Facebook. Originally published on Space.com.