Japanese startup Ispace confirmed the loss of its Resilience lunar lander on June 5, 2025, after the spacecraft failed to achieve a soft landing on the moon’s surface. The mission represents the company’s second unsuccessful attempt to become the first private firm outside the United States to execute a controlled lunar touchdown.
Resilience launched aboard a SpaceX Falcon 9 rocket on January 15, sharing the launch with Firefly Aerospace’s Blue Ghost 1 lunar lander. While Firefly achieved a successful landing in March, Resilience followed a low-energy trajectory, requiring over four months to reach the moon.
The spacecraft entered lunar orbit on May 6 and performed several orbital adjustments to establish a circular orbit at an altitude of 100 kilometres. During the final descent phase on June 5, telemetry indicated that the lander approached the surface at 187 kilometres per hour, significantly exceeding the safe landing velocity.
Contact with the spacecraft was lost approximately one minute and 45 seconds before the scheduled 3:17 p.m. Eastern touchdown time. Mission control displayed an altitude reading of negative 233 meters, indicating a telemetry malfunction before complete signal loss.
iSpace attributed the failure to delays in the laser rangefinder system used for surface distance measurements. “The laser rangefinder used to measure the distance to the lunar surface experienced delays in obtaining valid measurement values,” the company stated. “As a result, the lander was unable to decelerate sufficiently to reach the required speed for the planned lunar landing.”
The technical issue differed from the company’s first mission failure in April 2023, when software errors caused the Hakuto-R lander to miscalculate its altitude. Chief Technology Officer Ryo Ujiie confirmed that the laser rangefinder on Resilience employed a different design than the one used on Mission 1, as the original vendor had discontinued the earlier model.
The 340-kilogram dry mass lander carried multiple payloads valued at $16 million, including scientific instruments and commercial cargo. The primary payload was Tenacious, a five-kilogram rover developed by Ispace’s Luxembourg subsidiary, equipped with cameras and a sample collection scoop.
Under a $5,000 NASA contract awarded in 2020, ispace planned to transfer ownership of collected lunar regolith to establish precedence for space resource rights. Additional payloads included:
- Water electrolyser technology demonstration
- Food production experiments from Japanese companies
- A deep space radiation probe from the National Central University in Taiwan
- UNESCO memory disk containing the constitutional text in 275 languages
- Artistic payload “The Moonhouse” by Swedish artist Mikael Genberg
Technical Deep Dive: Lunar Landing Engineering Challenges
Guidance, Navigation, and Control Systems
Lunar landing presents unique engineering challenges that are absent in Earth-based operations or orbital manoeuvres. The moon lacks a substantial atmosphere, eliminating the need for aerodynamic control surfaces and parachute deployment options. Spacecraft must rely entirely on propulsive systems for deceleration and attitude control during descent.
Sensor Suite Architecture
Modern lunar landers employ multiple redundant sensor systems to determine altitude, velocity, and surface conditions. Primary sensors include:
Laser Rangefinders (LiDAR): Emit coherent light pulses and measure time-of-flight to calculate precise distance measurements. These systems operate effectively across varying surface reflectivity conditions but can experience delays when processing returns from highly reflective or absorptive materials.
Radar Altimeters: Utilise radio frequency signals for altitude determination, particularly effective during higher-altitude phases, but may struggle with resolving surface features during terminal descent.
Inertial Measurement Units (IMUs) provide acceleration and angular velocity data through gyroscopes and accelerometers, enabling dead-reckoning navigation when external references are unavailable.
Optical Navigation Systems: Process camera imagery to identify surface features and determine position relative to predetermined landing sites.
Terminal Descent Dynamics
The final descent phase requires precise coordination between multiple engineering systems. Spacecraft must transition from horizontal velocity vectors to vertical descent while maintaining attitude stability. This manoeuvre, known as the “pitch-over” or “flip maneuver,” represents a critical failure point where minor errors can cascade into mission-ending scenarios.
Propulsion System Constraints
Lunar landers typically employ bipropellant or monopropellant systems with limited throttling capabilities. Engine thrust must be modulated to achieve the required deceleration profile while accounting for the decreasing vehicle mass as fuel is burned. The absence of atmospheric pressure variations simplifies combustion dynamics, but it also eliminates the possibility of engine restarting if shutdown occurs prematurely.
Surface Interaction Challenges
Lunar regolith presents additional complications during the final touchdown. The fine-grained material can create dust clouds when disturbed by rocket exhaust, potentially contaminating sensors or creating visibility issues for optical systems. Landing legs must accommodate uneven terrain while maintaining vehicle stability across slopes up to 15 degrees.
Communication Latency Factors
Earth-moon communication delays of approximately 2.5 seconds prevent real-time mission control intervention during critical landing phases. Autonomous systems must execute pre-programmed sequences while adapting to unexpected conditions without ground support. This requirement places substantial demands on onboard processing capabilities and fault detection algorithms.
Environmental Considerations
Lunar surface temperatures range from -230°C to 120°C depending on solar illumination and local topography. Electronic systems must operate across these extremes while maintaining precision timing for navigation calculations. Thermal cycling effects can alter component characteristics and introduce calibration drift in sensitive instruments.
Despite the setback, Espace confirmed the continued development of two upcoming missions. Mission 3 will utilize the Apex 1.0 lander, built by ispace’s US subsidiary in partnership with Draper, scheduled for launch in 2027 as part of NASA’s Commercial Lunar Payload Services program targeting the moon’s far side.
Simultaneously, the company is developing the Series 3 lander design for Mission 4 in 2027, supported by an $80 million award from the Japanese government. CFO Jumpei Nozaki emphasized the competitive advantage of proven lunar landing capability: “If we can succeed in these missions, then we can show our ability to our customers.”
ispace’s failure occurs amid an increase in private sector lunar activity. Earlier in 2025, Firefly Aerospace achieved the first entirely successful commercial lunar landing, while Intuitive Machines completed a partially successful mission despite landing orientation issues.
The commercial lunar economy relies on reliable and cost-effective surface access. Companies like Ispace face technical challenges comparable to those encountered by national space agencies but with significantly constrained budgets and development timelines.
The Resilience mission failure highlights the complexity of autonomous landing systems operating in the lunar environment. If future missions successfully address rangefinder reliability issues, they could enable expanded commercial lunar operations, including sample return missions, technology demonstrations, and eventual human habitat construction.
CEO Takeshi Hakamada acknowledged the technical challenges while maintaining confidence in eventual success: “It’s hard to land on the moon, technically. We know it’s not easy. It’s not something that everyone can do.” The company’s transparent approach to failure analysis may accelerate industry-wide improvements in lunar landing technologies.
TLDR
- ispace’s Resilience lunar lander crashed on June 5, 2025, due to laser rangefinder delays preventing adequate deceleration
- The 340kg spacecraft carried $16 million in payloads, including the Tenacious rover and scientific instruments
- Technical failure differed from the 2023 mission, involving sensor hardware rather than software miscalculation
- The company plans two more missions: Apex 1.0 (2027) for NASA and Series 3 (2027) for the Japanese government
- Failure demonstrates ongoing challenges in autonomous lunar landing systems and surface proximity sensing
