Russia's Luna-25 Lunar Lander

[Yazata]

Luna-25 will be executing a lunar orbit injection burn in about five hours. It was launched atop a Soyuz from Vostochny cosmodrome (the new Russian launch site in the Russian far east) on August 10. It is scheduled to attempt a lunar landing on August 21. If it succeeds, it will be the first landing at the lunar south pole.

https://en.wikipedia.org/wiki/Luna_25

https://www.youtube-nocookie.com/embed/82H2J1bo-Os

[C C]

Russia’s Luna-25 crashed with Moon’s surface: Lunar probe’s final moments
https://www.bbc.com/news/world-europe-66562629

EXCERPT: Roscosmos, Russia's state space corporation, said on Sunday morning that it had lost contact with the Luna-25 shortly after 14:57pm (11:57 GMT) on Saturday. Preliminary findings showed that the 800kg lander had "ceased to exist as a result of a collision with the surface of the Moon", it said in a statement. It said a special commission would look into why the mission failed... (MORE - details)

[Yazata]

Russia’s Luna-25 crashed with Moon’s surface: Lunar probe’s final moments
https://www.bbc.com/news/world-europe-66562629

EXCERPT: Roscosmos, Russia's state space corporation, said on Sunday morning that it had lost contact with the Luna-25 shortly after 14:57pm (11:57 GMT) on Saturday. Preliminary findings showed that the 800kg lander had "ceased to exist as a result of a collision with the surface of the Moon", it said in a statement. It said a special commission would look into why the mission failed... (MORE - details)

Post by Roscosmos from Telegram:

Реализованные 19 и 20 августа мероприятия по поиску аппарата и вхождению с ним в связь результатов не дали.

По результатам предварительного анализа, в связи с отклонением фактических параметров импульса от расчетных, аппарат перешел на нерасчетную орбиту и прекратил свое существование в результате столкновения с поверхностью Луны.

Вопросами выяснения причин потери «Луны» займется специально формируемая межведомственная комиссия.
t.me/roscosmos_gk
/10540
590.7Kviewsedited
Aug 20 at 01:47

English translation from Google translate

The measures implemented on August 19 and 20 to search for the device and enter into communication with it did not yield results. According to the results of the preliminary analysis, due to the deviation of the actual impulse parameters from the calculated ones, the device switched to an uncalculated orbit and ceased to exist as a result of a collision with the surface of the Moon. The issues of clarifying the reasons for the loss of the "Moon" will be dealt with by a specially formed interdepartmental commission. t.me/roscosmos_gk /10540 590.7Kviewsedited Aug 20 at 01:47

[Yazata]

Katya Pavluchenko, who has very good sources within the Russian space program, writes that "the head of Roscosmos Yuri Borisov said that the main cause of the #Luna25 crash was an engine failure. Instead of the planned 84 seconds, he worked 127 seconds."

Scott Manley (a prominent space youtuber) replied, "So now I’m wondering why it was only 51% more. A completely stuck valve would run to depletion. Was the engine commanded to shut down multiple times? Was there separate watchdog code that kicked in at 50% excess. So many questions to be answered."

Katya replies: "If it helps, here the quote: “К сожалению, отключение двигателя произошло не штатно в соответствии с циклограммой, а по временной отсечке». I’m not sure how to translate it correctly, something like “the engine stopped working not nominally by flight profile, but by timing”.

When asked if it was a hardware or a software problem, she replied that they are still investigating.

[Yazata]

Photo from the Lunar Reconaissance Orbiter showing a new crater that appears to have been caused by Luna 25 impacting at high speed. (Marked by an arrow.)

[Image: F5GdYp8XEAAZ-7b?format=jpg&name=900x900]