Private Japanese Moon Lander Fails: Laser Navigator Identified as Cause of Crash

 

On June 5, 2025, the Japanese company ispace's Resilience lunar lander crashed during an attempt to achieve the nation's first private moon landing. The crash was attributed to an anomaly in the spacecraft's laser range finder (LRF), which failed to provide accurate altitude measurements during descent. This prevented Resilience from decelerating properly, leading to a high-speed impact in the Mare Frigoris region, also known as the "Sea of Cold." The company identified four potential causes: unexpected lunar surface reflectivity, improper laser angle, reduced laser power, or performance degradation due to radiation or high speeds. This marked ispace's second failed lunar landing, following a similar crash of its Hakuto-R lander in April 2023 due to a software error. Despite the setback, ispace plans to enhance testing and incorporate vision-based landing sensors for its upcoming Mission 3 and Mission 4, using a larger lander called Apex 1.0, scheduled for 2027. NASA's Lunar Reconnaissance Orbiter later captured images of the crash site, showing a dark smudge and debris

Here are the full details of the crash:

Cause of the Crash:

• Laser Range Finder (LRF) Anomaly: The primary cause of the crash was identified as a malfunction in the spacecraft's Laser Range Finder (LRF). This sensor is crucial for measuring the lander's altitude during its descent to the lunar surface.
  
  
• Inaccurate Readings: The LRF experienced an anomaly that prevented it from obtaining valid and timely measurements of Resilience's distance from the lunar surface. This meant the lander was essentially "flying blind" in its final descent phase.
  
  
• Insufficient Deceleration: Without accurate altitude data, the lander was unable to decelerate at the proper rate needed for a soft landing. Telemetry data indicates that the lander was descending at 42 meters per second at an altitude of 192 meters when communication was lost, crashing just five seconds later.
  
  
• Hardware, Not Software: Unlike the previous Hakuto-R mission failure which was attributed to a software issue, ispace has confirmed this was a hardware fault with the LRF. The LRF used on Resilience was from a new supplier, as the previous one had ceased manufacturing.

Possible Contributing Factors to the LRF Anomaly:

Ispace has identified four "likely causes" for the LRF's failure to provide accurate data:

1. Unexpected Reflectivity of Lunar Surface: It's possible the lunar surface exhibited unexpected reflective properties that interfered with the laser.
   
   
2. Angle of Laser: The angle of the laser relative to the lunar surface might have contributed to reduced reflectivity.
   
   
3. Lower Laser Power: Lower laser power on Resilience itself could have made the range finder's reflectivity too low for the spacecraft to correctly sense its surroundings.
   
   
4. Degraded Performance or Unexpected Behavior at High Speeds: The LRF's performance may have degraded during flight, or it simply did not perform as expected at the high speeds involved in the descent. Radiation could also have played a role in degrading performance.

Confirmation of Crash:

• NASA's Lunar Reconnaissance Orbiter (LRO) has since imaged the crash site, showing a dark smudge surrounded by a bright halo, which is characteristic of a spacecraft impact.

Ispace's Response and Future Plans:

• Commitment to Lunar Exploration: Despite two consecutive failures, ispace remains committed to its lunar ambitions and the development of a "cislunar economy."
  
  
• Corrective Actions: The company plans to implement several corrective actions for future missions, including:
  • Strengthening the testing and verification of its landing sensors, including LRFs.
  • Improving its landing system hardware.
  • Including further vision-based landing sensors (potentially LiDAR) on its next two missions.
• External Review and Collaboration: Ispace will convene an external review panel of third-party experts and expand collaboration with the Japan Aerospace Exploration Agency (JAXA) to strengthen its technical capabilities.
  
  
• Next Missions: Ispace's next two missions, Mission 3 and Mission 4, will utilize a larger and more capable lander called Apex 1.0. Mission 3 is currently scheduled for 2027, targeting the Schrödinger crater near the Moon's South Pole.

The crash of Resilience highlights the extreme challenges and complexities involved in achieving successful lunar landings, even for experienced space companies.