Russia launched the Luna-25 (Luna-25) probe. This is the first machine mission to the moon since the Soviet Union in 1976, but also Russia’s third space exploration spacecraft in the post-Soviet era, and this mission and the previous two ended in failure.
The Russian Luna-25 probe was scheduled to attempt a landing on the Moon on August 21, but on August 19 it collided with the Moon after an emergency situation made it “impossible to manoeuvre in accordance with the specified parameters” and deviated from its designed orbit.
Russia’s National Space Corporation (NSC) announced today that the most probable cause of the Luna-25 crash was a large number of commands sent at the same time, which resulted in the failure of one of the accelerometers of the angular velocity measurement unit to turn on, and ultimately triggered an abnormal functioning of the on-board integrated control system.
Simply put, these command data should have different priority settings so that the equipment can prioritize the execution of a certain item, the assignment of different priority commands has a certain degree of randomness, and the failure of Luna-25’s accelerometers to send out signals resulted in the onboard control system not being able to shut down the propulsion system in a time when the probe reached the predetermined speed, but rather shut down the propulsion system only after the thrusters had operated for a specified period of time.
Reflecting the actual process, the Luna-25 probe’s propulsion system changed from a circular near-lunar orbit to an elliptical landing orbit with the engines firing for 127 seconds instead of the planned 84 seconds, which ultimately led to an unintended trajectory and a collision with the Moon.
On the basis of the results of this investigation, Roskosmos will make recommendations to avoid the recurrence of such an incident in future missions.
