Japan's SLIM Lander Survives Its Second Lunar Night

Japan's SLIM (Smart Lander for Investigating Moon) has survived its second lunar night, a feat that has surprised many within the space community. The lander, which was not designed to endure the extreme cold temperatures of the lunar nights that can plummet to below -130 degrees Celsius, managed to re-establish communication after its second two-week-long night on the Moon, as confirmed by the Japan Aerospace Exploration Agency (JAXA).

Last night, we received a response from #SLIM, confirming that the spacecraft made it through the lunar night for the second time! Since the sun was still high and the equipment was still hot, we only took some shots of the usual scenery with the navigation camera. #GoodAfterMoon pic.twitter.com/5BjIr7vxMG
— 小型月着陸実証機SLIM (@SLIM_JAXA) March 28, 2024

Launched in September and having made its historic landing on January 19, SLIM marked Japan as the fifth nation to achieve a soft lunar touchdown. Despite an unexpected landing orientation that left its solar panels less optimally aligned for sunlight harvesting, the probe initially went dark but astonishingly woke up and began data transmission. After completing its primary mission objectives, which included making a precision landing and deploying two tiny rovers, SLIM was not anticipated to awaken after being put into hibernation mode in preparation for the lunar night.

This recent awakening not only underscores SLIM's unexpected durability but also brings to light the lander's challenges. Some of its temperature sensors and unused battery cells have begun to show signs of malfunction due to the harsh lunar conditions. Despite these adversities, the majority of functions that survived the first lunar night were maintained through the second, according to JAXA's updates.