Japan’s ispace sheds light on what may have caused the Resilience lunar lander failure.
The Moon is an unforgiving place. Early in June, ispace’s Hakuto-R2 Resilience lunar lander became the latest in a long line of missions to try the land on the Moon, only to fall silent.
The Japanese company ispace released the technical details that likely doomed the landing of their HAKUTO-R Mission 2 lunar lander earlier this month. According to a press release, their engineers narrowed down the issue to a failure of the spacecraft's Laser Range Finder (LRF). Engineers suspect that the LRF's performance deteriorated during flight, causing it to be slow to make its measurements and update its descent speed correctly. It hit the Moon at 42 meters a second, crashing hard.
The mission was a follow-on to ispace’s Hakuto-R1 Mission One lander, which crashed over the Atlas Crater site on April 25th, 2023. The failure for that particular landing was traced to the main computer misinterpreting radar altimeter data, keeping the lander in a 5 kilometer hover above the lunar surface until engine cutoff.
The landing is always the most challenging part of any mission, as the spacecraft must carry out an automated approach sequence and make judgments on its own. Miscalculating altitude or failing to spot a large boulder can make for a very bad day.
Resilience completed eight mission milestones successfully, from launch to lunar orbit insertion and maneuvering in lunar orbit. Analysis from the team confirmed that the lander was in a vertical configuration on approach… but delays in the lunar range finder measurements meant that the lander failed to decelerate on approach.
The range finder failure did not impact guidance, propulsion or power supply, which all operated as planned. The team then narrowed the range finder failure down to two possibilities: either an error in installation prior to launch, or degraded performance during flight.
The review rules out installation errors as unlikely, as no other anomalies were detected during testing or initial descent. This favors the deterioration of performance scenario. The ispace team will work to resolve this issue on further flights.
This comes after a long string of commercial and government failures for lunar landers. Japan’s SLIM lander made a lopsided landing on September 6th, 2023, as did Intuitive Machines’ IM-1 and IM2 missions; Astrobotic’s Peregrine Mission One failed to make it to the Moon entirely, crashing back to Earth and reentering ten days after liftoff. Russia’s Luna 25 mission also made a hard landing on August 10th, 2023.
Hakuto-R2 launched in tandem with Firefly Aerospace’s successful Blue Ghost lunar lander.
"Since the moment of the landing, we have remained committed to moving forward and identifying the root causes,” says Takeshi Hakamada (ispace CEO) in a recent press release. “ispace will not let this be a setback. We will not stop here, but as determined pioneers of the cis-lunar economy, we will strive to regain the trust of all stakeholders and embark on the next mission.”
But ispace is not down for the count just yet. Watch for ispace's Hakuto-R mission 3 in 2027, featuring the company’s new APEX 1.0 lunar lander. This will see the continued partnership between U.S. Japan and Luxembourg-based companies to head to the Moon.
Landing on the Moon is hard… and litho-braking is even harder. Hey, it took NASA several tries back in the early 1960s to even hit the Moon, with Ranger 4. Resilience is more than just a lander’s name, and ispace will take lessons learned and pay them forward to the next mission to the Moon.