Japan Lands Spacecraft on the Moon

After a successful soft landing, the craft’s solar cells weren’t charging and it was running out of power

In the distance, a rocket launches into a clear sky over clouds of smoke
Japan's X-ray Imaging and Spectroscopy Mission Smart Lander for Investigating Moon (SLIM) launched from Earth on September 7. SLIM took a fuel efficient route to the moon, touching down on the surface over four months later. JAXA

The Japan Aerospace Exploration Agency (JAXA) says they have successfully landed an uncrewed spacecraft on the moon.

The lander, called the Smart Lander for Investigating Moon (SLIM), reached the moon’s surface at around 12:20 a.m. Japan standard time on January 20, JAXA officials said in a press conference. While SLIM has been successfully communicating with Earth, its solar cells are not generating electricity, and the lander has only a few hours of battery life, officials said.

Japan now becomes the fifth country to achieve a soft landing on the moon, joining the Soviet Union, the United States, China and India. India landed the first spacecraft near the moon’s south pole in August.

Most of the equipment is working properly, officials said. They were unsure whether the solar cells are not charging because they are not functioning correctly or because they are not facing in the intended direction, though they didn’t think it was just a problem with the solar cells malfunctioning. The direction at which sunlight hits the moon changes every month, so the sunlight could later hit the solar cells and recharge the batteries, officials said.

SLIM aimed to demonstrate a precise landing on the moon’s surface. While landers typically aim for a region between several and tens of kilometers in size, SLIM attempted to land within 100 meters of a particular location. Officials said it would take time to determine whether SLIM’s landing had been this precise.

JAXA had aimed to land SLIM near a crater so that it could analyze the composition of rocks from the lunar mantle to better understand the moon’s origins, according to JAXA. Craters form when meteorites and other objects hit the moon, churning up debris from inside the moon, per CNN’s Ashley Strickland.

SLIM successfully launched from the Tanegashima Space Center in Japan on September 7, along with the X-Ray Imaging and Spectroscopy Mission (XRISM), which is equipped with two instruments for studying black holes, galaxy clusters, stellar explosions and more.

While XRISM remained in low-Earth orbit, SLIM continued on to the moon. Since SLIM traversed a route that would minimize fuel consumption, the journey took several months. The lander entered lunar orbit on Christmas Day. It began preparing to land on the moon on January 15, with the descent to the surface starting at midnight on January 20, Japan standard time.

SLIM was targeting an area near the Shioli crater, close to the Sea of Nectar. In order to land near the Sholi crater, SLIM had to land on a surface sloped at around 15 degrees, per JAXA. It had to tilt forward while descending toward the moon’s surface before touching down its main leg, followed by its front leg.

On its way down, SLIM also took pictures of the surface, which it used to correct its positioning as part of its “vision based-navigation.”

SLIM brought along two autonomous vehicles to explore the moon’s surface that would be released before SLIM landed, writes Mari Yamaguchi of the Associated Press (AP). JAXA officials said during the press conference that the two vehicles separated successfully.

The landing comes just a day after a moon lander from Astrobotic, an American company, burned up in Earth’s atmosphere. Due to a fuel leak, the spacecraft was unable to reach the moon.

A lander from the Japanese company Ispace crashed into the moon in April, as did a Russian lander in August, per CNN. JAXA also attempted a rocket launch in March, but intentionally destroyed it after an ignition failure, writes the AP.

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