The crash of Russia’s Luna-25 automatic interplanetary station is being attributed to faulty accelerometers, according to Yuri Borisov, the director general of Roscosmos. In a press conference, Borisov explained that the correction engine failed to halt based on data from the accelerometers, which are responsible for signaling changes in speed. He noted that the accelerometers did not activate, a malfunction that interrupted the sequence needed to guide the system toward its intended orbit.
Experts are actively investigating the incident to determine its causes. Borisov disclosed that there are sixteen potential scenarios under consideration, with eleven already confirmed as viable lines of inquiry. He estimated that the official investigation would complete by the end of September, providing a clearer understanding of what went wrong and why the system did not behave as planned.
Alexander Zheleznyakov, a former member of the Tsiolkovsky Russian Cosmonautics Academy, weighed in on the analysis, suggesting that the Luna-25 crash has implications for the broader Russian space program and its benefits. The mission, which involved the launch of the Soyuz 2.1b rocket from the Vostochny Cosmodrome on August 11 at 2:11 Moscow time, was intended to place the first domestic lunar lander into orbit around the Moon. The spacecraft entered lunar orbit on August 16, with plans to transition to a pre-landing orbit and perform a soft landing at the Moon’s South Pole on August 19 and 21, respectively.
However, on August 19 Roscosmos reported an emergency that prevented the transition to the pre-landing orbit with the specified parameters. The following day, the agency announced that Luna-25 had shifted to an off-design orbit, subsequently collided with the Moon and ceased to function. This sequence highlighted both the challenges of complex orbital maneuvers and the sensitivity of autonomous systems to anomalous readings that can cascade into mission-ending events.
Later remarks from Roscosmos indicated that the Luna-25 engine briefly exceeded the intended speed for about 43 seconds while attempting to enter orbit prior to landing, an overspeed that led to a collision with the Moon. The emergency commission established to study Luna-25’s operation has begun its work with the aim of detailing the conditions that produced the abnormal performance of the correction engine in the near future, and to identify corrective measures for future missions.
In the wake of the incident, Russian scientists and engineers are reflecting on the lessons learned, including improvements to sensor reliability, propulsion control, and flight software. The incident underscored the critical role of accurate sensor data in autonomous flight and the need for robust fault-detection and recovery capabilities in deep-space missions. While the immediate mission outcome was unsuccessful, the data gathered from the investigation is expected to inform ongoing and future efforts in lunar exploration and domestic spacecraft development.
As the investigation proceeds, Roscosmos and its partners will continue to publish findings in a controlled, methodical manner, emphasizing transparency and scientific rigor. The Moon, long a target of international interest, remains a focal point for space agencies worldwide, and Russia’s ongoing analysis of Luna-25’s failure will contribute to the global understanding of lunar entry, orbit insertion, and landing dynamics. The broader objective is to enhance mission reliability and to pave the way for subsequent domestic lunar endeavors that align with Russia’s long-term space exploration goals.