Tokyo-Based Ispace Reveals Cause of Lunar Landing Failure, Set to Try Again in 2024

The Yomiuri Shimbun

13:41 JST, May 27, 2023

Tokyo-based space company ispace on Friday explained the reasons behind the failure of its unprecedented private sector-based attempt to land on the moon.

The company said the landing craft’s control system had malfunctioned while hovering over the edge of a crater with an elevation change of approximately 3 kilometers. This caused a discrepancy between the estimated and actual altitudes, resulting in the craft crashing into the lunar surface.

The spacecraft encountered no significant problems on its journey to the moon. The company therefore plans to launch a similar lander in fiscal 2024 after addressing the control system problem through software improvements and other interventions.

The lander began its descent from an altitude of 100 kilometers above the lunar surface in the early morning of April 26. However, as it passed over the rim of a crater approximately 15 kilometers from the intended landing site, the sensor responsible for reporting altitude began to fluctuate significantly. The system erroneously inferred a sensor malfunction, leading to an incorrect altitude estimation.

As a result, while flying at an altitude of 5 kilometers, the lander misidentified its position as having already arrived at the lunar surface. About a minute later, the craft’s fuel ran out, causing it to plummet to the moon’s surface at a speed in excess of 360 kilometers per hour.

“Now that the cause is clear, we’ll be sure to use this knowledge to inform our future endeavors,” said ispace CEO Takeshi Hakamada at a press conference at the Japan National Press Club in Tokyo.

The company has set its sights on transporting goods to the moon and selling lunar surface data.