China is preparing to launch a new lunar relay satellite this Sunday, the precursor to a daring mission to the far side of the Moon later this year.
The satellite is called Queqiao, which translates to “magpie bridge”. It will be launched at about 5pm EDT on Sunday, May 20, on a Long March 4C rocket from the Xichang Satellite Launch Center.
The satellite, part of the overall Chang’e 4 mission, will be placed at a point of gravitational stability beyond the Moon called Lagrange point 2. From here, 64,000 kilometers (40,000 miles) beyond the far side of the Moon, it will be able to relay signals back to Earth.
Why is it being placed here? Well, later this year China is planning to launch a new lander and rover to the Moon as part of Chang’e 4. This will be the first landing ever attempted on the far side of the Moon, aiming to touch down in the Von Kármán crater in the South Pole-Aitken Basin, although that could change.
Since the Moon is tidally locked to Earth, one side of it always points towards us. Although it wobbles slightly in its orbit, we never see the far side. So to communicate with Earth from the far side, you need a satellite up above that’s in sight of our planet. Step forward Queqiao.
On board Queqiao will be a Dutch radio receiver called the Netherlands-China Low-Frequency Explorer (NCLE). In March 2019, this will unfurl three antennas, which will try to hear frequencies from the dawn of the universe, solar flares, Jupiter’s aurora, and more.
Landing on the far side opens up some rather interesting science, too. As it’s out of sight of Earth, it means it’s also out of sight of our radio signals. From here, you can listen to the cosmos without any interference from Earth.
So the lander will include an instrument to probe the universe from this quiet location. It'll also include a container with biological material inside, including potato seeds and silkworm eggs, to see if these can grow on the lunar surface. This experiment will be live-streamed back to Earth.
As for the rover, it’ll be equipped with some cameras and ground-penetrating radar to study under the surface. This will be the second rover China has sent to the Moon, with the first – Yutu – touching down in December 2013.
Before all that excitement, though, the Queqiao will have to successfully reach its intended orbit. If all goes to plan, though, we could see some major strides taken in lunar exploration by China, as the US also eyes up a return to the moon soon. Both plan to send humans there, too.