Japan's private lunar lander failed to make soft landing due to software glitch, analysis reveals

Japanese lunar exploration company iSpace has revealed that its HAKUTO-R Mission 1 lunar lander failed to achieve a smooth landing on the lunar surface due to a software glitch.

For the unversed, the HAKUTO-R Mission 1 lunar lander, which was launched atop a SpaceX Falcon 9 rocket from Cape Canaveral Space Force Station on December 11, 2022, was slated to touch down on the lunar surface on April 26. Unfortunately, the privately-funded spacecraft failed to make the historic touchdown.

According to the analysis of the flight data, on April 26, 2023, at 00:40 Japan Standard Time, the lander began its descent from an altitude of approximately 100 kilometers above the Moon. As the landing sequence progressed, an unexpected anomaly arose with the lander's altitude measurement. While the lander mistakenly registered its own altitude as zero, indicating contact with the lunar surface, it was later determined that it was actually around 5 kilometers above the surface.

After reaching the scheduled landing time, the HAKUTO-R lunar lander continued its descent at a reduced speed until its propulsion system exhausted its fuel supply. At that moment, the controlled descent of the lander abruptly came to a halt, and it is believed to have free-fallen to the lunar surface.

As already mentioned above, the primary cause of the unsuccessful landing was the software, particularly in the phase leading up to the touchdown.

iSpace said that it will integrate this information into future software designs, as well as the expansion of preparatory simulations for upcoming missions, including Mission 2 and Mission 3, to improve the accuracy and reliability of future lunar landing sequences.

"Mission 1 demonstrated a great deal of technical reliability, as our lander reached the lunar surface just prior to landing. Now, we have been able to identify the issue during the landing and have a very clear picture of how to improve our future missions. While it is unfortunate that we were not able to fully meet the expectations of all our stakeholders, including our customers, all of us at ispace are proud of what we accomplished in Mission 1 and are very positive about what we can accomplish," said Takeshi Hakamada, Founder and CEO of ispace.