Japanese company ispace has revealed the cause of its second lunar lander mission crashing, citing a hardware problem with the laser rangefinder used to determine altitude during descent. The failure occurred on June 5, when the Resilience spacecraft’s landing attempt ended in a crash.
The issue was discovered after analyzing telemetry data from the failed landing, which showed that the laser rangefinder provided incorrect readings as the lander descended. The unit, designed to provide altitude data when at least three kilometers above the surface, failed to trigger engines for the final landing burn until it was less than 900 meters high.
Further investigation revealed that the lander’s rapid deceleration resulted in a significant increase in speed, making it difficult for the laser rangefinder to provide accurate readings. The incident highlights several potential causes of the failure, including reduced laser light reflected back to the lander due to lunar surface conditions and effects from the space environment.
Despite the setback, ispace plans to enhance testing procedures for its laser rangefinder and related sensors, as well as consider a different model or augment it with additional sensors like lidar or cameras. The company has incurred approximately 1.5 billion yen ($10.3 million) in additional costs for future missions, but remains committed to regaining trust and moving forward with its next mission scheduled for 2027.
Source: https://spacenews.com/laser-rangefinder-problems-blamed-for-second-ispace-lunar-lander-crash