Tag Archives: Queqiao

China unfolds Dutch radio antennas on lunar relay satellite

Chinese engineers have unfolded and activated the Dutch radio antennas on Queqiao, their lunar relay satellite orbiting the Moon, an action that had been delayed because the lander Chang’e-4 and rover Yutu-2 had both exceeded their nominal mission on the surface.

The Chinese satellite was previously mainly seen as a communications satellite. However, the Chinese moon mission has by now achieved its primary goals. Consequently, the Chinese have redefined the satellite to be a radio observatory. As such, the Netherlands-China Low Frequency Explorer is the first Dutch-Chinese space observatory for radio astronomy.

Marc Klein Wolt, Managing Director of the Radboud Radio Lab and leader of the Dutch team, is happy: “Our contribution to the Chinese Chang’e 4 mission has now increased tremendously. We have the opportunity to perform our observations during the fourteen-day-long night behind the moon, which is much longer than was originally the idea. The moon night is ours, now.”

If Queqiao is now dedicated to being a radio antenna full time during the lunar night, I wonder if this means the Chinese are shutting down Chang’e-4 and Yutu-2. Up to now both spacecraft have only operated during the lunar night, which suggests that was the only time they could relay data. It is possible that data relay could take place at other times, and that the lander and rover can function autonomously, but I have my doubts.

Both Chang’e-4 and Yutu-2 functioned for twelve lunar nights, four times longer than planned, so shifting gears on Queqiao to do radio astronomy is not unreasonable. Unfortunately, the lack of transparency from China leaves us in the dark about the fate of Chang’e-4 and Yutu-2.

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China launches communications relay satellite for upcoming lunar mission

China successfully launched a satellite in the early hours this morning designed to relay communications between the Earth and an upcoming lunar lander aimed for the Moon’s far side.

The landing site for this mission is expected to be the Von Kármán crater in the South Pole-Aitken Basin. If successful, this will be the first spacecraft to land on the far side of the Moon.

As such, a communication relay will be required to communicate with Earth. Queqiao [the communication satellite’s name] will provide that role. Launched to an eventual L2 Halo Orbit (Earth-Moon L2 Lagrange Point), the satellite will have a lifetime of five years, covering both this and potentially another Chang’e mission.

The spacecraft is based on the CAST100 small satellite platform, with commonality to the often used DFHSat system that finds its way on to a number of Chinese spacecraft. It has a mass of 425kg and uses a hydrazine propulsion system. It will transmit telemetry back to Earth via its S-band antenna, while X-band data will provide the communication path between the lander and rover.

This Chinese lander could also be the first to confirm the existence of water ice on the lunar surface.

With this launch China once again ties the U.S. in launches for 2018. The leaders:

15 China
9 SpaceX
5 Russia
5 ULA

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