The Luna-25 interplanetary station, which vanished after colliding with the Moon, may have failed due to a malfunction in the Bius-L navigation device. This detail was reported by RIA News citing a source.
According to the source, Bius-L determines the direction and velocity of the spacecraft. It passes this data to Luna-25’s onboard computer, which then commands the engine. The device, however, had not undergone space testing.
“Between a new product and a proven device, the safer choice is the latter,” the source remarked.
Luna-25
Luna 24 was launched by the Soviet Union in 1976. Nearly five decades later, a new Russian mission aimed to land on the Moon. The spacecraft lifted off from Vostochny Cosmodrome in the Amur region on August 11 and was scheduled for a soft touchdown on August 21. By August 19, communication with the probe had been lost. Preliminary analyses suggested that Luna-25 veered off course due to discrepancies between actual and planned impact parameters.
Earlier reports noted that Luna-25 briefly entered lunar orbit and transmitted the first images back to Earth. The mission documented a micrometeorite impact on the surface of Luna-25.
Luna-25 was designed for extended scientific work, including soil analysis of Earth’s natural satellite, studying the southern polar region’s surface layer, examining how solar wind influences the lunar exosphere, and assessing the upper atmosphere’s outer layer.
The failure of Bius-L is considered a potential cause among several possibilities for the Luna-25 incident. The final conclusions will come from the emergency commission.
“No Luna-25 instrument has ever been tested in space”
In an interview with Ivan Moiseev, president of the Institute of Space Policy, the outlet reported his expectation that the Bius-L issue would be a likely explanation. Moiseev suggested that the accelerometer’s role in measuring acceleration, integrating the data, and processing timing could be a source of miscalculation, noting the device’s complexity.
The expert emphasized that none of the station’s devices had space-tested, a situation he described as common. He added that while similar components might fly into space, the components on the station rarely do. In rare cases, tests may occur at the institute, but those are exceptions. Typically, devices are developed and launched commercially because sending hardware into space and returning it is extremely challenging.
Moiseev cautioned against expecting a quick turnaround for a new station without supporting documentation and funding.
Local origins of Bius-L
The Bius-L inertial unit, which measures angular velocity and linear acceleration affecting the spacecraft, was developed entirely from Russian components at the Research and Production Center of Automation and Instrumentation named after Academician NA Pilyugin. This claim was confirmed by Alexander Sapozhnikov, the center’s first deputy chief designer.
“The device was developed and produced in roughly a year and a half, which is an unusually tight schedule for this type of task. Under normal, non-emergency circumstances, such a project typically takes 3–4 years,” Sapozhnikov said.
He noted that cooperation with the foreign company Astrix was initially planned but became impossible due to sanctions. Bius-L measures angular velocity and the letter L stands for the Moon. It performed well during flight, but landing remains the most challenging phase. The center’s representative said maximum power would be required for that maneuver.
According to the expert, the device was originally planned for use on missions to other planets as well, with a service life of about 15 years.
Roscosmos’ remarks after the failure
The Roscosmos head, Yuri Borisov, spoke on the Russia 24 network, attributing the Luna-25 crash to abnormal engine operation. He reported that at 14:10 on August 19, the engines were activated to secure the device and place it in a pre-landing orbit, but the shutdown did not occur as planned and ran for 127 seconds instead of 84.
Borisov added that the setback also reflected decades of paused lunar work, which forced experts to re-specialize across technologies.
“We must draw lessons from such events. We cannot give up and must pursue results. I met with the developers at NPO Lavochkin who are continually advancing lunar missions. A new generation of engineers is ready to try again, and we will do everything in our power for this,” stated the head of Roscosmos.
Future space plans
Despite Luna-25’s failure, Russia’s space program continues. Luna-26 was planned for 2027, though officials anticipate acceleration. “By speeding up Luna-26 and Luna-27, we will surely recover the momentum lost with Luna-25,” Borisov remarked.
Plans also include the Boomerang project to reach Mars’ moon Phobos to collect soil samples by 2030, as reported by TASS. The Expedition-M initiative aims to study Mars and its moons Phobos and Deimos through remote and contact missions.