Japan Moon lander survives lunar night

Japan’s Moon lander has survived the harsh lunar night, the sunless and freezing equivalent to two Earth weeks.

“Last night, a command was sent to #SLIM and a response received,” national space agency Jaxa said on X.

The craft was put into sleep mode after an awkward landing in January left its solar panels facing the wrong way and unable to generate power.

A change in sunlight direction later allowed it to send pictures back but it shut down again as lunar night fell.

Jaxa said at the time that Slim (Smart Lander for Investigating Moon) was not designed for the harsh lunar nights.

It said it planned to try to operate again from mid-February, when the Sun would shine again on Slim’s solar cells.

“The news that SLIM has rebooted itself after the cold lunar night is significant,” said Dr Simeon Barber from the UK’s Open University. “Surviving lunar night is one of the key technological challenges to be overcome if we are to establish long-lived robotic or human missions on the Moon.”

Dr Barber explained that Slim landed near the Moon’s equator, where the lunar surface reaches more than 100C at noon, but then plunges to -130C during the lunar night.

Jaxa said that communication with the lander was terminated after a short time – it was lunar midday, meaning the temperature of the communications equipment was very high.

It said preparations were being made to resume operations when instrument temperatures had cooled sufficiently.