Japan’s “Moon Sniper” lander has defied the odds for a third time, surviving yet another long, frigid lunar night despite not being designed to endure such harsh conditions, according to the Japan Aerospace Exploration Agency.
Temperatures during the lunar night can plunge to minus 208 degrees Fahrenheit (minus 133 degrees Celsius), according to NASA. And Moon Sniper wasn’t expected to withstand even one lunar night, which is a period of darkness on the moon lasting about two weeks.
The robotic vehicle, also known as SLIM, or the Smart Lander for Investigating Moon, initially touched down on the lunar surface on January 19. The historic feat made Japan the third country this century, and the fifth ever, to land on the moon. The spacecraft touched down near the Shioli Crater, located about 200 miles (322 kilometers) south of the Sea of Tranquility, a region near the lunar equator, where Apollo 11 first landed humans on the moon.
During descent, the spacecraft experienced an anomaly and landed on its nose, which meant its solar panels were facing west rather than upright and not receiving necessary sunlight to generate power. The lander had just enough energy to send back a mosaic of images before shutting down. The mission’s team in Japan remained hopeful that once sunlight could reach the solar panels again, the spacecraft might reawaken.
So far, Moon Sniper, which gained its nickname for the precision technology that allowed it to land about 55 meters (180 feet) from its target, keeps pleasantly surprising the team by waking up after each lunar night, taking new photos and transmitting them back before it goes back to sleep. The vehicle’s resilience in the face of lunar extremes is unique among missions that have landed on the moon in the past year, and experts have a couple ideas as to why that might be.
The mission team communicated with Moon Sniper on April 23 after the lander rode out its third lunar night. The spacecraft was able to transmit more images of its landing site.
“SLIM has maintained main functionality even after 3 nights on the Moon, which was not anticipated in the design!” the team shared on x formerly known as Twitter. In addition to surviving the extreme cold of the lunar night, Moon Sniper has also endured the searing temperatures of the lunar day, which can reach 250 degrees Fahrenheit (121 degrees Celsius), according to NASA.
The team shared that it’s closely monitoring SLIM’s condition in order to identify what components of the spacecraft could deteriorate over time as it experiences more of the lunar day and night environment.
JAXA engineers have been careful about how they communicate with SLIM when it first wakes up since the spacecraft is operating in such high temperatures, which could heat up the cameras and damage them. As a result, the mission team usually waits about a day after SLIM wakes up before commanding it to send back images.
So far, one of SLIM’s navigation cameras and the spacecraft’s Star Tracker have provided images from Moon Sniper’s experience on the lunar surface. The Star Tracker isn’t a true camera and instead was used to measure the direction of the spacecraft by tracking the alignment of the stars as the lander traveled to the moon. But the team has taken clever measures to make the most of Moon Sniper’s wonky landing.
“It was not originally planned to be used on the lunar surface, but in principle it can take pictures just like a camera, which led to its operation through ‘secret commands,’” the agency shared on X.
The spacecraft has two navigation cameras mounted in different directions. Given how Moon Sniper landed, one of those cameras is facing into space, but the other has a view of the landing site from the spacecraft’s perspective.
