Zak: Phobos-Grunt Doomed by Computer Design, Testing Flaws, Not U.S. Radar

Zak: Phobos-Grunt Doomed by Computer Design, Testing Flaws, Not U.S. Radar

The Russian commission investigating the failure of the Phobos-Grunt (Phobos-soil) Mars mission concluded that computer design error and insufficient testing were the reasons the probe never left Earth orbit, not interference from a U.S. radar according to Anatoly Zak at  Zak summarizes the commission’s findings on his website today.   Russia’s news agency Itar-Tass reported over the weekend that the findings would  be presented to Russia’s space agency director yesterday and made public this week, but neither it nor other leading Russian media sources have published anything yet today.

Zak reports on his website that the “most probable cause … was a simultaneous robooting of two operational processors in the main computer….  The computers could crash as a result of errors in their software or as a result of some external reasons, such as electromagnetic incompatibility, industry sources said.  The mentioning of this last point … apparently became a basis for numerous reports in the Russian press blaming the failure on various improbable external reasons, such as foreign radars or solar flares.”

“Foreign radars” refers to assertions by some Russian officials that a U.S. radar based in the Marshall Islands inadvertently damaged Phobos-Grunt while it was being used to study asteroids and the orbiting spacecraft passed through the beam.  Yuri Koptev, former head of the Russian space agency who chaired the commission investigating the Phobos-Grunt failure, said that his group would conduct an experiment to prove or disprove the theory.

Zak reports that tests were conducted by NPO Lavochkin, which manufactured Phobos-Grunt, to determine if the computer could have been affected “by interference from the probe’s own power supply or from unlikely external sources, such as a narrow powerful beam of a ground radar.  During these tests, the computer withstood all simulations without any problems.”

Therefore, “[w]ith all external failure scenarios effectively debunked, the most probable cause of the failure was narrowed down to the lack of integrated testing” of the computer, Zak states.

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