ispace HAKUTO-R Mission 1 lunar lander crash
Japan's ispace lost its first commercial lunar lander during the final moments of descent, a total loss of the mission.
The damage was public. The root cause was preventable.
Japan's ispace lost its first commercial lunar lander during the final moments of descent, a total loss of the mission.
What the software actually got wrong
The lander's software measured a sudden 3km jump in altitude as it passed over a crater rim, incorrectly concluded its sensor was faulty, and discarded all further altitude readings; it then continued a slow, controlled descent from its last trusted (and wrong) altitude estimate until it ran out of propellant and fell to the surface.
The lander's software measured a sudden 3km jump in...
The lander's software measured a sudden 3km jump in altitude as it passed over a crater rim, incorrectly concluded its sensor was faulty
Requs AI Edge Case flags this exact pattern at the requirements and architecture stage — before a single line of code implementing it exists — so the assumption behind it gets challenged while it is still cheap to fix.
Discarded all further altitude readings
discarded all further altitude readings
Requs AI Software FMEA traces this failure mode back to the system-level hazard it feeds, tagging it against the Common Defect Enumeration so it surfaces in review instead of in the field.
It then continued a slow, controlled descent from its...
it then continued a slow, controlled descent from its last trusted (and wrong) altitude estimate until it ran out of propellant and fell to the surface
Requs AI Edge Case and Software FMEA together treat this as a known, catalogued defect pattern — not a novel surprise — so it gets tested for deliberately rather than discovered after deployment.
Beyond code coverage and "shall" testing
Root causes like this one rarely show up in code coverage or requirements-compliance testing, because nobody wrote a requirement anticipating the specific edge case that broke. Requs AI Edge Case and Requs AI Software FMEA are built to surface exactly this class of overlooked failure mode — before the software is written.
Surfaces this before code exists
Identifies edge cases like this one at requirements and architecture time, using the Common Defect Enumeration to catalog failure patterns seen across hundreds of real-world software failures — including this one.
Connects the failure mode to the hazard
Traces this class of root cause directly to the system-level hazard it can produce, so a defect pattern like this one gets flagged during design review instead of after it ships.
Find the overlooked root causes before they ship.
Schedule a demonstration, or explore how Requs AI Edge Case and Software FMEA use the Common Defect Enumeration.