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Japan’s “Lunar Sniper” lander has defied the odds for the third time and managed to survive another long, cold lunar night despite not being designed to withstand such harsh conditions, according to the Japan Aerospace Exploration Agency.
Lunar night temperatures can drop to minus 208 degrees Fahrenheit (minus 133 degrees Celsius), according to NASA. And Moon Sniper wasn’t expected to survive even a lunar night, a dark period lasting about two weeks on the moon.
The robotic vehicle, also known as SLIM or Intelligent Lander for Lunar Exploration, first touched down on the lunar surface on January 19. This historic achievement made Japan the third country to land on the moon this century and the fifth so far. The spacecraft touched down near Shioli Crater, about 200 miles (322 kilometers) south of the Sea of Tranquility, an area near the lunar equator where Apollo 11 first landed humans on the moon.
But things didn’t go quite as planned.
During descent, the spacecraft experienced an anomaly and landed on its nose, meaning its solar panels were facing west instead of upright and did not receive the sunlight needed to generate power. The lander had enough energy to send out a mosaic of images before shutting down. The mission’s team in Japan was hopeful that the spacecraft could wake up again when sunlight reached its solar panels again.
So far, Moon Sniper, which gets its nickname from the precision technology that allows it to land approximately 55 meters (180 feet) away from its target, continues to pleasantly surprise the team by waking up after each lunar night, taking new photos and sending them back. before falling asleep again. The rover’s endurance in the extreme conditions of the moon is unique among missions that landed on the moon last year, and experts have a few ideas as to why this might be the case.
riding the moon night
The mission team contacted Moon Sniper on April 23 after the lander emerged from its third lunar night. The spacecraft was able to transmit more images of the landing area.
“SLIM retained its core functionality even after 3 nights on the Moon, which was unexpected by design!” The team shared: Xformerly Twitter.
In addition to surviving the extreme cold of the lunar night, Moon Sniper also withstood the scorching temperatures of the lunar day, which could reach 250 degrees Fahrenheit (121 degrees Celsius), according to NASA.
The team shared that it is closely monitoring SLIM’s condition to determine which components of the spacecraft may deteriorate over time as it experiences more of the Moon’s day and night environment.
JAXA engineers were careful about how to communicate with SLIM when it first woke up because the spacecraft operates at temperatures high enough to heat the cameras and cause damage. As a result, the mission team typically waits about a day after SLIM wakes up before giving the command 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. Star Tracker is not a real camera and was instead used to measure the spacecraft’s orientation by tracking the alignment of stars as the lander traveled to the moon. But the team took smart precautions to make the most of Moon Sniper’s risky landing.
“It was not originally planned to be used on the lunar surface, but in principle it can take photographs just like a camera, which leads to its operation through ‘secret commands,’” the agency shared on X.
The spacecraft has two navigation cameras mounted in different directions. Considering how Moon Sniper lands, one of these cameras is looking into space, but the other sees the landing site from the spacecraft’s perspective.
The sun set once again near Shioli Crater, and Moon Sniper went into hibernation again on April 29, according to the agency.
“We plan to restart operations in mid-to-late May, when SLIM’s solar cells begin producing electricity. As Moon Sniper fell asleep once again, the agency posted the following on X: Thank you for your continued support.
Members of the mission team recently composed a song they called “” in honor of Moon Sniper’s inspiring journey.15 Degree Tilt.” Team members shared on
The song takes its name from the steep slope Moon Sniper is planned to descend. The mission team now believes the slope the Moon Sniper landed on was about 10 degrees, which is still “surprisingly steep.”
A tale of two moon landings
In February, Houston-based space exploration company Intuitive Machines landed the uncrewed IM-1 mission, also known as Odysseus, on the moon’s south pole, making it the first commercial spacecraft and the first U.S.-built spacecraft to make a soft landing on the moon. But like SLIM, the “Odie” mission had a bit of a bumpy lunar journey experience, including having to rely on experimental technology to get to the ground and eventually land on its side.
After seven days of operation, on February 29, Odie fell asleep because he was not planned to survive the lunar night. The Intuitive Machines team kept an ear out in case Odie woke up in March, but the spacecraft never called home again.
“Odie was designed only to support payloads, none of which were suitable for lunar night, so we didn’t design it for anything more,” said Jack Fischer, former NASA astronaut and vice president of manufacturing and operations for Intuitive Machines. “There were measures we could take to potentially allow it to last longer, but we focused on supporting our payloads by flying them economically and quickly, as opposed to a nation-state-sponsored mission.”
Odie landing near the moon’s south pole and SLIM landing near the equator could affect the chances of surviving the lunar night, Fischer said.
“This still depends on the terrain, but the equator will generally have less trouble with shadows and more efficient solar energy production (due to higher angles of incidence) compared to what Odie experienced at the South Pole,” he said.
Other factors that could increase survivability include protecting a chemical battery, operating in extreme temperatures, and a design that can feed solar energy directly into the power system; Both of these could be implemented in the future.
“Surviving at night is critical to any effort to build meaningful infrastructure on the Moon, and IM is working on a number of options with experiments as soon as we have the IM-3 mission,” Fischer said. “Our goal is to first ‘survive’ the night, where the spacecraft goes into a sort of hibernation (like SLIM does) and wakes up on the other side. “Ultimately, we want to ‘thrive’ during the night, and we’re doing that with our Lunar Lander program, where the rover can do meaningful work during the lunar night.”
Fischer tipped his hat to JAXA for the continued success of its mission.
“While I’m not an expert on the design of the vehicles, it’s quite an achievement for the spacecraft to survive three lunar nights, regardless of the conditions,” Fischer said.
race to the moon
Japan’s success with Moon Sniper is just one entry into the renewed moon landing race that has been going on for the past few years.
India became the fourth country to land a robotic mission on the moon in August 2023 when the Chandrayaan-3 mission landed near the moon’s south pole. The Vikram lander and the Pragyan six-wheeled rover it deployed studied the moon for about two weeks before shutting down to sleep during the lunar night; but attempts to reawaken them were unsuccessful.
The push for lunar exploration continues as China seeks to land a sample collection mission on the far side, or Earth-facing side, of the Moon, and NASA aims to establish a sustained human presence at the Moon’s south pole through its ambitious Artemis program. .
Moon Sniper’s continued success comes during what Noah Petro, NASA’s project scientist for both the Lunar Reconnaissance Orbiter and Artemis III, calls “a great new era in lunar exploration.”
Six of the groundbreaking Apollo missions returned lunar samples from different landing sites on the Moon, but they were all on the near side of the moon. Exploring new lunar regions provides new windows into understanding Earth’s moon.
“For me, it is a great joy to see missions land on the lunar surface,” Petro said. “Each time we land on the surface, we learn more about this unique lunar environment we enter. “Building this database of lunar knowledge about what it means to be on the moon and what it means to work on the lunar surface helps us better prepare for Artemis missions.”
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