Chang'e 5 Lunar Ascent

The ascent from the lunar surface of the Chinese Chang'e 5 lunar sample return mission was observed by radio. This dataset presents a recording of the X-band radio signal of the Chang'e 5 ascent module, which transmits at 8463.75 MHz. These recording were obtained from Roberts Creek, Canada, at latitude 49.4348N deg, longitude 123.668W deg, height 40 m. The ascent from the lunar surface occurred at 2020-12-03T15:10:24, data from the ascent module sitting on the lunar surface starts the recordings.

A 66 cm parabolic dish was used to receive the X-band transmissions. System performance is estimated to be 66 cm @ 50% illumination at 8.43 GHz is 32.3 dBi. 136K is 21.3 dBK. G/T = +11 dB/K. approximately.

The ‘gqrx_20201203_150513_8463750000_200000_fc.raw’ dataset consists of complex sampled (IQ) 32 bit floating point values (interleaved real/imaginary), sampled at 2 Msps at a centre frequency of 8463.75 MHz. This dataset begins at 2020-12-03T15:05:13 UTC.  The RF system was locked to a GPS disciplined oscillator. NOTE: near the end of this data set there is a brief period where the receiver is knocked off frequency that can be seen in the step divergence from the trend in the data. The receiver is re-tuned to proper tuning and the trend can be seen to continue.

The second data set ‘2020-12-03_ce5_lunar_launch.zip’ is dynamic spectra of signal recorded on a different receiver connected to the same RF path is also provided. These are averaged to 100Hz frequency resolution and 1 second time resolution and stored as 32 bit floating point values. Each spectrum of 20000 channels is preceded by a human readable header of 256 bytes, providing metadata. No discontinuities are known in the second dataset. Timestamps in UTC are embedded in the file.