Japan's SLIM probe regains power week after moon landing

Japan's SLIM spacecraft has regained power, its space agency said on Monday, more than a week after it achieved an unconventionally precise lunar landing but ran out of electricity because its solar panels were at the wrong angle.

The Japan Aerospace Exploration Agency (JAXA) re-established communication with its Smart Lander for Investigating Moon (SLIM) late on Sunday, a JAXA spokesperson said, nearly nine days after the probe's touchdown made Japan the fifth country to put a spacecraft on the moon.

The probe was likely able to generate power thanks to a change in the sunlight's direction, JAXA said.

SLIM resumed its operations to analyse the composition of olivine rocks on the lunar surface with its multi-band spectral camera, in search of clues about the origin of the moon, the agency added.

It touched down on the moon within 55 m of its target in a crater near the lunar equator on Jan. 20. JAXA said it proved an advancement in what it called vision-based "pinpoint" landing - a technology that could be a powerful tool for future exploration of hilly moon poles seen as a possible source of fuel, water and oxygen.

SLIM lost the thrust of one of its two main engines shortly before the touchdown for unknown reasons and ended up drifting a few dozen metres away from the target. The lander safely stopped on a gentle slope but appeared toppled with an engine facing upward in a picture taken by a baseball-sized wheeled rover it deployed.

The probe's solar panels faced westward due to the displacement and could not immediately generate power. JAXA manually unplugged SLIM's dying battery 2 hours and 37 minutes after the touchdown as it completed the transmission of the lander's data to the earth.

JAXA does not have a clear date when SLIM will end its operation on the moon, but the agency has previously said the lander was not designed to survive a lunar night. The next lunar night begins on Thursday.

The Lunar Excursion Vehicle 2 (LEV-2 / SORA-Q) has successfully taken an image of the #SLIM spacecraft on the Moon. LEV-2 is the world’s first robot to conduct fully autonomous exploration on the lunar surface. https://t.co/NOboD0ZJIr pic.twitter.com/mfuuceu2WA

— JAXA Institute of Space and Astronautical Science (@ISAS_JAXA_EN) January 25, 2024