The Luna-25 AMC crashed during a change of orbit. What happened?
AMS Luna-25 collided with the surface of the Earth's satellite
MOSCOW, Aug 20 — RIA Novosti, Tatiana Pichugina. The Luna-25 spacecraft ceased to exist as a result of a collision with the surface of the Moon, Roscosmos reported. An emergency situation arose yesterday afternoon when trying to transition to a pre-landing orbit, as a result, communication with the device was lost. It was not possible to restore it. A preliminary analysis of the situation showed that the station crashed.
How is the Luna-25 flight going?
Luna-25 is a fully automatic, Earth—controlled vehicle weighing 1.6 tons. It was designed by specialists of NPO Lavochkin, relying on the knowledge gained during Soviet lunar missions, but the filling is completely new. Engineers of NPO Lavochkin determined the conditions of the flight to the Moon and the available launch windows, calculated the trajectory, maneuvering, pre-landing and landing orbits. There were about 30 kilograms of scientific equipment on board, created at the ICI of the Russian Academy of Sciences.
The AMS was supposed to land on the main site measuring 30 by 15 kilometers north of the Boguslavsky crater with coordinates: 69.55 south latitude and 43.54 east longitude. Approximately at this latitude, the Russian Antarctic station Novolazarevskaya is located at the South Pole of the Earth. The main task of the mission is to search for water ice in the polar region of our satellite.
The launch took place on August 11 at the Vostochny Cosmodrome. The Soyuz-2.1b rocket put the AMS on a suborbital trajectory, the Fregat upper stage accelerated to enter the flight path to the Moon, then separated.
The next day, the first trajectory correction was performed, on August 13 — the second, on August 16, the station entered the circular polar orbit of the Moon, becoming its artificial satellite. At this stage, scientific equipment was prepared. The cameras of the STS-L onboard television have been calibrated to shoot the lunar surface in the colors we are familiar with.
On the seventeenth of August, scientific observations began. Specialists of the ICI RAS conducted several equipment inclusions, in particular the neutron and gamma-ray spectrometer HADRON-LR. It was he who had to look for ice in the ground.
The ARIES-L ion energy-mass analyzer, designed to study the near-surface ion exosphere in the polar region of the Moon, was also tested.
In addition, the PmL device was tested to register microparticles levitating near the surface of the Moon and determine the parameters of the surrounding plasma. At the same time, a micrometeorite impact was registered, most likely from the Perseid meteor shower. It turns out that Luna-25 successfully crossed it during the flight.
On the eighteenth of August, at 09:20, the engine was started for 40 seconds. "The correction took place normally, all onboard systems of Luna-25 are working normally, the connection is stable," the press service of Roscosmos reported.
During the flight, the onboard television system (STS-L), developed at the ICI RAS with the participation of MIIGAIK, sent several photos to Earth. Four wide-angle and four narrow-angle cameras perform, among other things, panoramic, and stereo photography.
The first images were received on August 13 from a distance of about 310 thousand kilometers. The structural elements of the device are visible against the background of the Earth, the mission emblem and the bucket of the onboard manipulator. Another picture was received on August 16.
The station sent a picture of the lunar surface from the polar circular orbit on August 17. This frame captures the southern polar crater Zeeman on the far side of the moon.
What happened in lunar orbit
Next, the AMS was supposed to descend into a pre-landing orbit with an altitude of 18 kilometers at the lowest point and land at about noon on August 21, using high- and low-thrust engines.
Braking started on August 19 at 14 hours 10 minutes.
"During the operation, an emergency situation occurred on board the automatic station, which did not allow the maneuver to be performed with the specified parameters. Currently, the specialists of the management group are analyzing the situation," Roscosmos informed.
A discussion of the emergency situation unfolded in social networks. Experts recalled that the disruption of communication with spacecraft is not uncommon. So, at the end of July, NASA lost communication with the Voyager-2 probe for two weeks when the antenna was reoriented. However, its location was known, unlike Luna-25.
Experts explained what interferes with the orbital rotation of the Earth. When the Moon goes over the horizon, ground-based communication facilities in Russia do not see the device.
At night, a number of telegram channels reported on a meeting at Lavochkin's NGO with the participation of the first Deputy Director for Development and Promising Projects of Roscosmos, Alexander Ivanov. According to unofficial information, the device received a braking impulse one and a half times more than the calculated one. This means a descent from orbit and a collision with the surface.
There were technical problems before the launch. However, according to the interlocutors of RIA Novosti, they seem to have been solved.
A leading researcher at the Space Research Institute (ICI) spoke about the "alarming signs" before the transition to the pre-landing orbit RAN Nathan Eismont. In his opinion, it was necessary to postpone the maneuver.
According to some reports, there were difficulties with the pulse-Doppler radar measuring altitude, which is why the launch was postponed several times.
The crash of the AMS Luna-25 was reported on August 20 at 11:52. Communication with the device was interrupted on August 19 at 14:57 when trying to form an elliptical pre-landing orbit, Roscosmos clarified.
"The measures implemented on August 19 and 20 to search for the device and get in touch with it did not give results. According to the results of the preliminary analysis, due to the deviation of the actual parameters of the pulse from the calculated ones, the device moved into an unaccountable orbit and ceased to exist as a result of a collision with the surface of the Moon," the official communique says. An interdepartmental commission will investigate the causes of the accident. The crash site of the station is unknown.
What's next
Luna-25 is the third Russian interplanetary mission that ended in failure. In 1996, we lost the Mars-96 spacecraft, and in 2011, the Phobos-Grunt probe did not leave Earth's orbit. Both vehicles are submerged in the Pacific Ocean. At the same time, there were two very successful orbital scientific projects — the Radioastron radio telescope and the Spectrum-RG X-ray-gamma telescope, and Russia also participated in the first stage of the Exomars mission in 2016.
The Soviet Union sent 24 spacecraft to the moon. The latter delivered more than a hundred kilograms of soil to the Ground. It was in these samples that GEOCHA scientists found water, which marked the beginning — after observational confirmation of this fact in the 2000s - of a new lunar race.
It is worth noting that the flight to the moon and landing is an extremely difficult undertaking. On the surface of the Earth's satellite there is a cemetery of vehicles that have made planned and unplanned hard landings — more than 80. In 2019, the Indian landing module "Chandrayan-2" and the private Israeli probe "Bereshit" crashed. In April 2023, the Japanese private company Ispace lost a landing station with two lunar rovers on board. In May, NASA aborted the mission of a small probe (cubesat) Lunar Flashlight, which could not enter lunar orbit.
Experts believe that, most likely, the Russian lunar program will have to be revised. So, State Duma deputy Anton Gorelkin wrote in the telegram channel: Roscosmos needs to conduct a deep analysis of all the circumstances of the incident and take them into account in the work on Luna-26.
If everything had been normal with Luna-25, the Luna-26 orbiter and the Luna-27 landing station with a drilling rig and a lunar rover would have followed.
Currently, four spacecraft are operating in orbit of the Moon: the American Lunar Reconnaissance Orbiter station, the Indian Chandrayan-2, the Korea Pathfinder Lunar Orbiter (KPLO), launched last year by South Korea, the Indian Chandrayan-3 probe with the Vikram lander, which is preparing for a lunar landing in the southern polar region on August 23. And on August 26, another Japanese lander with a lunar rover will go to the moon.
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