Japan Moon Lander Set for Launch Monday; JAXA Aims to Bring It Down Within 100 Meters of Target

The Yomiuri Shimbun

6:00 JST, August 28, 2023

The Japan Aerospace Exploration Agency on Monday will launch the Smart Lander for Investigating Moon (SLIM) from the Tanegashima Space Center in Kagoshima Prefecture.

If it succeeds in landing on the moon, Japan will become the world’s fifth country to do so, joining the former Soviet Union, the United States, China and India.

Measuring about 1.7 meters long, 2.7 meters wide and 2.4 meters high, SLIM will attempt a pinpoint landing within 100 meters of a targeted spot on the lunar surface. This would be an order of magnitude better than previous missions, in which the landing accuracy ranged from a few kilometers to a dozen kilometers from the target.

“This mission will lead to future lunar exploration,” said SLIM Project Manager Shinichiro Sakai, 50. “We definitely want to make it successful.”

After the launch, SLIM will use the gravity of the Earth and the moon to follow an orbit requiring less fuel and reach lunar orbit in three to four months. It will likely try to land on the moon around January or February next year.

SLIM will attempt to land near a crater of Mare Nectaris located on the equatorial south side of the moon’s near side. After quickly estimating its current position from images of the lunar surface taken during the flight, it will then descend vertically, avoiding obstacles.

If it lands successfully, it will analyze rocks.

Lunar landings require high levels of expertise. The moon has one-sixth the gravity of the Earth, but there is no atmosphere, so parachutes cannot be used. A landing attempt was made by the Tokyo-based space company ispace, inc. in April, and by Russia’s Luna 25 this month, but both failed.

The polar regions of the moon are believed to contain water resources. The United States and China have announced plans to build a lunar base.

However, there are only limited areas in the polar regions that are suitable for exploration, so precise landing technology is needed.

“SLIM is the only lander said to be able to perform pinpoint landings,” said Sakai. “As competition in lunar exploration intensifies, this could be a decisive factor for Japan.”

Launch delayed again

SLIM will be carried on the H-2A No. 47 Launch Vehicle rocket.

The launch was initially scheduled for Saturday but postponed to Sunday due to weather conditions. It was then postponed again to 9:26 a.m. Monday, as result of lightning and bad weather being forecast at the Tanegashima Space Center, Mitsubishi Heavy Industries, Ltd. announced.

In addition to SLIM, the X-Ray Imaging and Spectroscopy Mission (XRISM) will also be onboard the H2A rocket.