World’s smallest lunar lander from Japan will put ham radio transmitter on the moon

12/09/2021

from Japan OMOTENASHI, the world’s smallest lunar lander, will have an X-band and UHF communications system, although it will not carry an amateur-band transponder. OMOTENASHI is a 6U CubeSat intended to be launched via a NASA SLS rocket from February 2022. It will have a mission duration of 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’s (JAXA) Ham Radio Club, JQ1ZVI, said radio amateurs can play a role in collecting data from the spacecraft.

The spacecraft is made up of two separable components, both with independent communication systems – an orbit module and a surface probe. The orbiting module will bring the surface probe to the moon. It will transmit beacon or digital telemetry data over UHF (437.31 MHz). The surface probe – the lunar lander – will transmit digital telemetry or an analog three-axis acceleration wave with FM modulation over UHF (437.41 MHz). The power of the transmitter will be 1 W in both cases.

“If we are successful in receiving the UHF signal from the surface probe, we might know the acceleration data on the impact on the moon and the success of the landing sequence,” Torii explained.

“We already have an uplink and downlink station in Wakayama, Japan – used as 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 amateur radio stations around the world. Torii noted that the lander’s RF system only works on UHF.

The in-orbit 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 Torii for more information.