Is the cause of the Phobos-2 probe failure definitively known?
In 1987 the ambitious Soviet probe Phobos (Fobos)-2 made it to Martian orbit and started transmitting data. The Planetary Society Phobos-2 page shows all 38 images received over a period of about a
Is the cause of the Phobos-2 probe failure definitively known? Ask Question Asked 7 years ago Modified 7 years ago Viewed 4k times 7 In 1987 the ambitious Soviet probe Phobos (Fobos)-2 made it to Martian orbit and started transmitting data. The Planetary Society Phobos-2 page shows all 38 images received over a period of about a month. On March 27 the probe maneuvered to image the moon Phobos, breaking the comm link to Earth, and sadly, communications were never re-established. It's difficult to find good information on this mission because of the amount of UFO nonsense associated with it on the internet. russianspaceweb has the most authoritative writeup I found, but it lists no conclusion as to the failure. Yet, again, a human error at ground control was blamed for the failure, however details were not immediately made public. (392) One post-Cold War source cited the failure of the attitude control system. (270) The loss of onboard transmitter or a main flight control computer was also considered. The latter was probably the most likely failure scenario, since the system had exhibited potential problems earlier. (The first sentence quoted refers to the sister Phobos(Fobos)-1 mission which was lost due to a command error.) Is there any official failure investigation report or other authoritative source which lists a most probable cause? (Sources are listed in the linked article, but they themselves are not linked and are in Russian. No source is given for the "most likely failure scenario".) probefailurephobos Share Improve this question Follow asked May 11, 2019 at 13:58 Organic Marble 201k10 10 gold badges 709 709 silver badges 920 920 bronze badges I posted an answer but i'll add a comment here, list of trustworthy sources whenever anything soviet-era related comes up: spacehistory101.com/category_s/1835.htm If Asif Siddiqi or Bart Hendrickx or Brian Harvey hasn't written about it, it probably didn't happen :) – kert Commented May 11, 2019 at 16:43 1 Thanks! the sources in your answer look great. Both I and abebooks thank you :) – Organic Marble Commented May 11, 2019 at 16:56 @kert The link is not working anymore – Swike Commented Aug 29, 2024 at 10:25 Archive link still works: web.archive.org/web/20160812074132/https://… – kert Commented Aug 31, 2024 at 2:59 Add a comment 1 Answer Sorted by: Highest score (default) Date modified (newest first) Date created (oldest first) 9 There is a pretty good description in the book "Soviet Robots in the Solar System: Mission Technologies and Discoveries" Summarizing: Received radio signals indicated spacecraft had lost attitude control and tumbled, and ran out of battery power a few hours later due to this. The investigation concluded that the root causes of this was inadequate onboard software architecture to deal with "emergencies", i.e. no safe mode to orientate the spacecraft towards sun. The original upset event likely came from a processor error, and the voting architecture deal with these errors was deemed inadequate as well. Another book, "Space Systems Failures" by Harland and Lorenz offers a similar description, attributing the failure to inadequacy of the onboard computing architecture, specifically in the voting logic. Share Improve this answer Follow edited May 11, 2019 at 16:51 Organic Marble 201k10 10 gold badges 709 709 silver badges 920 920 bronze badges answered May 11, 2019 at 16:33 kert 1,34010 10 silver badges 14 14 bronze badges Add a comment Your Answer Sign up or log in Sign up using Google Sign up using Email and Password Post as a guest Name Email Required, but never shown Post Your Answer By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy. Start asking to get answers Find the answer to your question by asking. Ask question Explore related questions probefailurephobos See similar questions with these tags. 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