A Ham Radio Transmitter on the Moon
World’s Smallest Moon Lander
The Story of OMOTENASHI
Japan’s OMOTENASHI, the world’s smallest moon lander, will have an X-band and UHF communication system, although it will not carry an amateur band transponder. OMOTENASHI is a 6U CubeSat set for launch via a NASA SLS rocket as early as February 2022. It will have a mission period of from 4 to 5 days. The name is an acronym for Outstanding Moon Exploration Technologies demonstrated by Nano Semi-Hard Impactor.
Wataru Torii of the Japan Aerospace Exploration Agency (JAXA) Ham Radio Club, JQ1ZVI, said radio amateurs can play a role in gathering data from the spacecraft. The spacecraft is made up of two separable components, both having independent communication systems — an orbiting module and a surface probe. The orbiting module will take the surface probe to the moon. It will transmit beacon or digital telemetry data on UHF (437.31 MHz).
The surface probe — the moon lander — will transmit digital telemetry or three-axis acceleration analogue-wave with FM modulation on UHF (437.41 MHz). Transmitter power will be 1W in both cases.
“If we succeed in receiving the UHF signal from the surface probe, we could know the acceleration data on the impact on the moon and the success of the landing sequence,” Torii explained, “We already have a station for uplink and downlink at Wakayama in Japan — used as an EME [‘Moon-bounce’] station. However, if the satellite is invisible from Japan, we cannot receive the downlink signal. So, we need a lot of help from ham radio stations worldwide.”
Torii noted that the RF system on the lander only operates on UHF. The orbiting module beacon will transmit on 437.31MHz using PSK31. The surface probe beacon will transmit on 437.41MHz using FM, PSK31, and PCM-PSK/PM.
(Source: ARRL | Amateur Radio / Ham Podcast | Colin Butler)