A catastrophic computer crash caused by space radiation penetrating non space qualified components caused the failure of the Russian Phobos Sample Return mission as it tried to initiate a firing sequence to propel itself to Mars, according to the Russian investigation team headed by Yuri Koptev, former head of the Russian space program.
The failure commission, created by the Federal Space Agency, studied more than 700 documents related to Phobos spacecraft construction, as well as data from its short-lived flight.
The Phobos mission was doomed before it launched on a powerful Zenit rocket November 9, 2011,” said Louis Friedman, a retired Jet Propulsion Laboratory manager and former Executive Director of The Planetary Society. He is also Principal Investigator on the Phobos LIFE experiment that was supposed to have evaluated living organisms making a round trip between Earth and Mars on the Phobos lander.
Friedman obtained an unofficial transcript of the failure report. He wrote in the Planetary Society Blog that “Cheap parts, design shortcomings, and a lack of pre-flight integration and testing ensured that the spacecraft would never fulfill its goals.”
Friedman says the officially released final report presents three main conclusions which he paraphrased here from a cursory and unofficial translation for the Planetary Society Blog carried in the Feb. 6 edition of “The Planetary Report,” the society’s respected journal. They are:
1. Everything was working well with the spacecraft immediately after launch, including deployment of the solar panels, until the command to start the engines was issued. When that did not happen, the spacecraft went into a safe mode, keeping the solar panels pointed to the Sun to maintain power.
2. The spacecraft computer failed when two of the chips in the electronics suffered radiation damage. (The Russians say that radiation damage is the most likely cause, but the spacecraft was still in low Earth orbit beneath the radiation belts.) Whatever triggered the chip failure, the ultimate cause was the use of non-space-qualified electronic components. When the chips failed, the on-board computer program crashed.
3. There was inadequate ground-testing of all spacecraft components.
“Other errors on the mission included the system being designed so that the spacecraft was out of communications range after launch, so mission personnel had no idea how it was behaving. In this, the Russians repeated the error that doomed their Mars-96 mission,” Friedman concluded.
Russian Space expert Anatoly Zak, has also been gathering failure details from the report and other sources for his website The Russian Space Web.
He quotes the investigative report as summarizing: “The most likely factor which caused a “[double computer reboot]” was a local influence of heavy charged particles from space. This influence led to errors in the random-access memory modules in the computer during the second orbit of the mission.
Errors in RAM modules could be caused by intermittent interference caused by heavy space particles on particular cells in computer modules, which contain two chips of the same design (type WS512K32V20G24M) .
The influence of heavy particles caused a distortion of the computer code and activated a “guard” timer, which in turn triggered a reboot. The investigation commission recommended developing and implementing new certification guidelines which would contain updated models of ionized radiation in space.
The Russians have begun discussing the kind of robotic (or even manned) mission that it could fly by about 2020 to recover from the Phobos mission loss. Although executed poorly, few unmanned space missions, once made known to the general public, generated the excitement of the Phobos sample return mission as envisioned in the You Tube video below.