Japanese startup Ispace has concluded that a hardware anomaly in a laser-based landing sensor caused the failure of its Mission 2 lunar landing earlier this month, the company announced Tuesday.

The company’s “SMBC x Hakuto-R Venture Moon” lander, officially named Resilience, made a hard landing on the lunar surface in the early hours of June 6.

After 18 days of technical review, Ispace concluded that the laser range finder (LRF) — a key sensor used to measure altitude during descent — failed to provide accurate data in the final phase of landing, leaving the lander unable to slow down in time.