12/09/2021

Japan's OMOTENASHI[1], 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 analog-wave with
FM modulation on UHF (437.41 MHz). Transmitter power will be 1 W 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 [moonbounce] 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 437.31 MHz using PSK31. The surface
probe beacon will transmit on 437.41 MHz using FM, PSK31, and PCM-PSK/PM.

Contact[2] Torii for more information.

[1] https://www.isas.jaxa.jp/home/omotenashi
[2] mailto:torii.wataru@jaxa.jp

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