A look at Chang’e 5 telemetry

Chang’e 5 is a Chinese lunar sample return mission. It was launched a few days ago on 2020-11-23 from Wenchang and is estimated to perform lunar orbit injection on Saturday. Since then, a number of Amateurs such as USA Satcom, Paul Marsh M0EYT, Scott Tilley VE7TIL, Fer IW1DTU and others have been receiving the X-band signals from the spacecraft and posting reports over on Twitter. Meanwhile, r00t.cz has been working in decoding the frames, which has led him to the amazing achievement of being able to retrieve a short video from the signal.

In this post I will look at some of the frames demodulated by USA Satcom and Paul during the first couple of days of the mission. The frame structure has many similarities with Tianwen-1, which I have described in several posts, such as here and here. However, there are some interesting differences.