Speaker
Description
Japan launched a lunar landing spacecraft ``SLIM” in 2023. The spacecraft landed on Moon surface on January 19th 2024, with an accuracy of around 50 meters. The attitude of the landed spacecraft was not perfect, but it survived for several months after landed, when the solar cells of the spacecraft was Sun-shined.
The authors installed a small rover for SLIM spacecraft. The rover named ``LEV-1'' had a mass of approximately 2.1 kilograms, with an autonomous capability to explore around the landing area by a hopping mobile system.
The rover was deployed onto the Moon a few meters above the surface just before the spacecraft landed. After the deployment, it made a fully autonomous exploration with no help from the mother spacecraft. The obtained data were directly transmitted to the Earth with no relay by the lander. The obtained data included images, which disclosed the landed mother spacecraft. The rover survived for 107 minute after the deployment until the loss of the signal on the Ground.
The rover had S-band and UHF transmitters. The S-band transmitter was only used on the Moon, whereas the UHF transmitter was mainly used during the flight to the Moon. LEV-1 required battery charge before the deployment from the mother spacecraft in order to fully charge the onboard battery. During the battery charge operation, the status of the rover was transmitted by UHF radio.
The UHF transmitter used amateur radio frequency and the radio from it was received all over the World. The UHF transmitter was also switched on when the rover was on the Moon surface. Thus LEV-1 became the World-first amateur radio station on the Moon. The main carrier of the UHF ratio included morse code to inform the status by the strength of the signal.
The S-band radio signal was received by several parabolic antennas from domestic space agency and USA Deep Space Network. The domestic antennas only decoded a signal from one spacecraft, and was dedicated to receive the radio from the mother spacecraft. Thus we constructed an independent reception system, which recorded the radio signal from LEV-1. The recorded signal was replayed in our laboratory to extract the telemetry using software GNU-radio technologies.
This paper describes the radio system of LEV-1 rover as well as the actual operation made after the Moon landing.
| Talk Length | 30 Minutes |
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