Japanese Lunar Lander Reactivated Following Two-Week Mandatory Rest Period

In the latest update from the Japanese space program Jaxa, it has been reported that the Japanese lunar lander SLIM has been reactivated after enduring two weeks of the moon night – a period when the moon is plunged into complete darkness after a fortnight of continuous daylight. This cycle is a unique characteristic of the moon’s rotation and revolution around the Earth.

To give further insight, the term ‘lunar night’ is used to describe the time when the part of the moon facing Earth does not receive sunlight due to the moon’s position relative to the Sun and Earth. During this period, temperatures on the moon can drop drastically, making the lunar night a harsh time for any equipment or instruments on the moon. A typical lunar night lasts for approximately 15 days and temperatures can plummet below -160 degrees Celsius, posing a significant challenge for any lunar missions.

Jaxa, in its recent update, stated “Last night, a command was sent to SLIM and a response was received, confirming that the device outlasted the lunar night and retained its ability to communicate.” The communication with SLIM was, however, cut off shortly as it was still noon on the moon and the communication temperature was extremely high. Jaxa assured that they are making preparations to resume operations once the instrument temperatures have cooled sufficiently.

The Smart Lander for Investigating Moon (SLIM) made its successful landing on the moon, 55 meters from its original target, on January 20. This marked Japan as the fifth country to make a successful moon landing, joining the ranks of the United States, the Soviet Union, China, and India. However, it is worth noting that due to an engine issue during the final meters of descent, SLIM landed at an angle, causing its west-facing photovoltaic cells to miss out on capturing sunlight. As a result, SLIM ended up in a small crater named Shioli. Before going into hibernation during the lunar night, the lander was successful in unloading two mini-rovers, tasked with conducting analyses on rocks from the moon’s internal structure, specifically the lunar mantle.