News Navigator: Why did Japan’s moon lander fail to touch down?

The Mainichi Shimbun answers some common questions readers may have about the recent failure of a Japanese moon lander’s mission and the difficulties of touching down on Earth’s natural satellite.

Question: Why did the spacecraft gather attention?

Answer: That moon lander was developed by the Tokyo-based private company ispace Inc. and was launched aboard a U.S. rocket in December last year. In April this year, it attempted what would have been the world’s first private-sector lunar touchdown, but failed just before landing.

Q: What happened?

A: After flying to about 100 kilometers above the planned landing site on the moon, the spacecraft began its descent, during which communications were lost. The company explained, “There is a strong possibility that it ran out of fuel and crashed into the lunar surface.” The moon’s gravity is one-sixth of the level on Earth, but it still requires a large amount of fuel to decelerate and land while maintaining a proper balance. In this case, there was an error in the measurement of the altitude above the landing site, and it is possible that the spacecraft ran out of fuel even though it had not yet landed.

Q: It seems very difficult to land on the moon, doesn’t it?

A: There is almost no atmosphere like on Earth, so a parachute cannot be used for deceleration, which makes landing difficult. Also, the lunar surface is covered with sand called regolith, and the impact of landing on the moon can cause it to fly up and damage the engine and other components.

Q: It must have been a great achievement for humans to land on the moon a long time ago, right?

A: The first human landing on the moon was in 1969 with the U.S. spacecraft Apollo 11. It was a success after a series of failures and preparations. Moves to return to the moon are gaining momentum again in the world today, and ispace plans to make another landing attempt.

(Japanese original by Yurika Tarumi, Lifestyle, Science & Environment News Department)