Japan’s Slim lander comes back online to resume moon mission

29 Jan 2024

Illustration of the Slim spacecraft. Image: The Japan Aerospace Exploration Agency (JAXA)

The country became the fifth country to successfully land a spacecraft on the moon’s surface, but the lander was unable to charge its power from the sun until now.

Japan has reestablished contact with its lightweight moon lander after being forced to turn it off for more than a week, allowing the country’s lunar mission to continue.

The Slim (Smart lander for investigating the moon) probe successfully landed on the moon on 20 January, making Japan the fifth country to successfully land a spacecraft on the moon’s surface.

But the landing did not go entirely as planned, as the space probe landed in a way that had its solar cells pointing away from the sun – preventing it from recharging its power. The Japan Aerospace Exploration Agency (JAXA) opted to switch off the Slim lander to allow for a possible recovery.

A change in the angle of sunlight has changed the lander’s fortune, as JAXA confirmed today (29 January) that it successfully re-established communications with Slim and resumed its mission of analysing the moon. The Japanese agency shared a new image from the spacecraft’s multi-band camera of a “toy poodle” – a small section of moon rock near the lander.


The Slim mission aims to show the viability of a  small-scale, lightweight probe system that cuts weight for higher function observational equipment. It is also hoped that the pinpoint landing technology on Slim can be used for future lunar probes.

Japan’s successful moon landing follows a failed private sector attempt last year, after Japanese start-up iSpace lost contact with its lunar lander. The Hakuto-R lunar lander successfully entered the moon’s orbit in March, but iSpace lost contact with the spacecraft as it rapidly descended to the moon’s surface.

Meanwhile, India made history last year by becoming the fourth country to successfully land on the moon – and the first to land on the south pole of the moon.

That landing happened two days after Russia’s Luna-25 mission, which was attempting to land in the same region as India, crashed into the lunar surface after running into difficulties. It was the first lunar mission Russia has launched since 1976, during the time of the Soviet Union.

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Leigh Mc Gowran is a journalist with Silicon Republic