by Japan is on the moon – for a few hours, at least.
The nation’s robotic SLIM spacecraft touched down on the surface of the moon this morning (January 19), marking a major success for Japan: It has become only the fifth nation to soft-land on Earth’s closest neighbor.
“First of all, the landing was successful,” Yamakawa Hiroshi, president of the Japan Aerospace Exploration Agency (JAXA), said during a post-landing press conference today (in Japanese; English translation provided by a translator during the briefing).
Going forward, “we should be able to access the surface of the moon,” Hiroshi said. “I believe a path is opening for that now.”
The other countries in the moon landing club are the Soviet Union and the United States, which made their first trips to the lunar surface during the Cold War space race; China, whose initial landings took place in December 2013; and India, whose Chandrayaan-3 lander-rover duo touched down last August.
But it wasn’t all good news for SLIM: The probe’s solar panels aren’t generating electricity as intended on the moon’s surface, JAXA officials said during today’s briefing. If the problem is not solved soon, SLIM could go silent forever. Its battery can support operations on the moon for several hours.
Related: Missions to the Moon: Past, Present and Future
SLIM (short for “Smart Lander for Investigating Moon”) was launched last September, along with an X-ray space telescope called XRISM. The scope was deployed into low Earth orbit shortly after liftoff (and recently sent home its first test images), but SLIM has mapped out celestial shores further afield.
The probe took a long winding path towards the moon, finally arriving in lunar orbit on Christmas Day. Its initial orbit was highly elliptical, taking SLIM within 373 miles (600 kilometers) of the lunar surface at its closest point and 2,485 miles (4,000 km) away at its furthest point.
Early Sunday morning (January 14), SLIM performed a critical engine burn, circling its orbit at an altitude of 373 miles and setting the stage for takeoff and landing operations.
Those operations intensified with another burn this morning, which took SLIM’s orbit down to about 9 miles (15 km) above the moon’s surface. And they finished with the landing attempt, which began today at about 10 am EST (1500 GMT; midnight on January 20 Japan time) and wrapped up 20 minutes later.
Everything seemed to be going well: SLIM hit its various milestones during the descent, and the lander communicated with its handlers all the way through, and beyond, its historic prediction. However, JAXA was unable to confirm SLIM’s status immediately after landing. About an hour later, the agency gave us an update through the press conference, explaining the probe’s power problems.
It is not clear why the solar cells are not working, JAXA officials said. But it is unlikely that they were damaged during the touchdown, because other SLIM hardware seems to be fine and functional. The lander may not be pointing towards the sun as expected, according to JAXA.
Related: Facts about JAXA, the Japanese space agency.
SLIM aimed to land within 330 feet (100 meters) of its target location on the edge of Shioli Crater, explaining the probe’s nickname “Moon Sniper”.
“While significant in their own right, the landing ambitions of this mission are critical to the future of scientific lunar exploration,” the Planetary Society wrote in a mission description.
“Global interest in the moon is growing, with many nations and commercial entities entering the field,” added the nonprofit advocacy group, which is led by former TV “Science Guy” Bill Nye. “As lunar exploration progresses, it will be necessary to target specific sites to address significant science questions. The SLIM mission architecture hopes to change the standards of lunar landing missions, from targeting locations where it’s easy to lay down exactly when they want.”
SLIM appears to have achieved the desired landing accuracy, JAXA officials said during the press conference, although it may take about a month for the mission team to confirm that conclusion.
SLIM also aimed to show that small, relatively cheap spacecraft are capable of great feats of exploration. The probe weighs just 440 pounds (200 kilograms) without a propellant, and its mission cost about 18 billion yen ($120 million US) to develop, according to The Planetary Society.
RELATED STORIES:
— Japan’s SLIM lunar lander completes critical 1st phase in Earth orbit
— A private Japanese lander hits the moon after being confused by a crater
— The moon: Everything you need about Earth’s companion
Although SLIM is primarily a lander technology demonstrator, it was designed to perform some science work during its surface missions, which were expected to last one lunar day, or about two Earth weeks. (SLIM has no heaters to protect its electronics on the frigid moonlit night.)
SLIM aimed to study its surroundings – the Mare Nectaris (“Nectar Sea”) patch, located about 15 degrees south of the lunar equator – using its onboard spectrometer. The instrument’s data could reveal insights into the composition of the area, which could, in turn, shed light on the moon’s formation and evolution – but the chance to do so won’t exist unless panels become available. SLIM solar in operation.
SLIM also carried two tiny rovers – a small drone called LEV-1 and a ball-shaped craft called LEV-2. (“LEV” is short for “Lunar Excursion Vehicle.”) These small robots were designed to be deployed by the SLIM parent company, collecting some data of their own and taking photos.
The data shows that both LEV-1 and LEV-2 deployed as planned, JAXA officials said today. And LEV-1 is known to be working, adding to the mission’s achievements.
SLIM was not the first Japanese spacecraft to aim for a lunar crash. NASA’s Artemis 1 mission, which sent an uncrewed Orion capsule to lunar orbit and back in late 2022, landed the tiny lander nation known as OMOTENASHI. But OMOTENASHI’s handlers were unable to establish communication with the probe, and its probe was abandoned. attempted landing.
The private Hakuto-R lander launched in April 2023 but failed. Hakuto-R, built and operated by the ispace company in Tokyo, went into lunar orbit but went into a crash orbit during its test after becoming confused by the rim of a lunar crater.
Editor’s note: This story was updated at 1 pm EST on January 19 with news that SLIM has successfully landed but is dealing with a power problem.
