• Technology

Japan Becomes 5th Country to Successfully Land Lunar Probe on Moon; Possibly Unable to Power Itself


A space probe launched by Japan has successfully landed on the moon, the Japan Aerospace Exploration Agency (JAXA) said Saturday.

Japan’s Smart Lander for Investigating Moon (SLIM) made a successful landing, making the country the fifth one to do so after the former Soviet Union, the United States, China and India.

However, the solar cells onboard SLIM has been unable to generate electricity, which could hinder the planned exploration.

The latest achievement has increased Japan’s presence among various countries that are becoming increasingly active in lunar exploration.


According to JAXA, SLIM began its final flight at an altitude of about 15 kilometers above the moon about 20 minutes before landing. As it headed toward the landing site near Mare Nectaris, an area located near the moon’s equator, the vehicle analyzed data from images of the lunar surface taken by an onboard camera installed on the vehicle, automatically correcting its trajectory.

Once SLIM reached above its target area near the Shioli crater, it descended vertically, mainly by hovering, and touched down on the lunar surface at 12:20 a.m. Saturday. As SLIM’s communication with Earth was normal, JAXA announced a successful landing.

While the landing accuracy of conventional space probes is several kilometers or more, SLIM is aiming for the world’s first pinpoint landing with an accuracy of within 100 meters. Data analysis, likely to take about a month, will be necessary to determine whether this was achieved.

“SLIM followed its planned trajectory,” Director General of JAXA’s Institute of Space and Astronautical Science, Hitoshi Kuninaka, said at a press conference the same day.

In addition, two small robots with cameras — LEV-1 and SORA-Q —were successfully separated from SLIM shortly before the landing, and radio waves were detected from one with communication capabilities. The robots will take pictures of the landed SLIM and other objects, and send the image data back to Earth.

LEV-1, which weighs about 2.1 kilograms, moves by leaping around on the lunar surface. The SORA-Q, measuring 8 centimeters in diameter and weighing 250 grams, transforms from a sphere and moves on wheels. It was developed by toymaker Tomy Co. and others.

It was also discovered that solar cells installed on SLIM were unable to generate electricity. It is possible that the solar panels may not be facing the sun because the vehicle overturned when landing.

JAXA originally planned to analyze the composition of lunar rocks using a camera onboard SLIM, but now it is unclear whether this will be possible. “When the direction of the sun changes, and light comes from a different direction, the batteries may be restored,” said Kuninaka.

However, no other notable problems have been confirmed.

“The path to the moon has opened up,” said JAXA President Hiroshi Yamakawa. “By achieving the technology to make our probe land where we want to, we can cooperate internationally.”