Thursday, January 19, 2012

Space - Did the US accidentally zap Phobos-Grunt?

Where did it all go wrong? <i>(Image: STR/AFP Files/AFP/Getty)</i>
Where did it all go wrong? (Image: STR/AFP Files/AFP/Getty)

First there were cries of sabotage, although there was never a clear motive. Now the bizarre suggestion that the US shot down Russia's Phobos-Grunt space probe has morphed into a slightly less strange claim. A Russian newspaper has reported that radar beamed from a US military base could have accidentally damaged the probe, leading to its demise.
The spacecraft launched on 9 November with the aim of returning soil samples from the surface of Mars's largest moon, Phobos, but mysteriously failed to fire its upper-stage rocket and became stranded in Earth orbit until it re-entered the atmosphere on Sunday. How plausible is the suggestion that radar is to blame for the probe's failure?

What is the latest accusation?
Yesterday the Russian newspaper Kommersant quoted an unnamed source who said that tests are being undertaken in Russia to determine whether radar beams from a US military base could have caused a failure in the Phobos-Grunt power system that prevented its engines from firing.

Which radar beams would those be?
The unnamed source implicates the US military radar station on Kwajalein atoll in the Pacific Marshall Islands. At the time of Phobos-Grunt's malfunction, the source says that the station was using its radar to bounce signals off asteroids, a standard technique for imaging asteroids and measuring their distances. So any such US-inflicted damage to Phobos-Grunt could have been accidental, not sabotage, as had been darkly hinted earlier by Vladimir Popovkin, head of Russia's space agency Roscosmos.

Is it possible that radar could damage a craft like Phobos-Grunt?
According to Boris Smeds, a former radio engineer at the European Space Agency, it is highly unlikely. Deep space communications, such as those you would expect Phobos-Grunt to use, use different frequencies from those of space-observation radars, and spacecrafts' receivers are built to filter out unwanted frequencies. It is just conceivable that a badly filtered radio receiver on Phobos-Grunt was damaged by a radar beam from the US military base, but it is extremely unclear how that damage could affect the power system of the spacecraft.

Any other possibilities for how a radar beam could be to blame?
Smeds conceded that it could interfere with radio reception, temporarily "deafening" a spacecraft. Still though, the firing of Phobos-Grunt's upper stage was supposed to be automatic, pre-programmed into the spacecraft before launch, so would not have relied on receiving a radio signal.

Will we ever know what happened to Phobos-Grunt?
Yuri Koptev, chairman of the scientific and technical council of the Russian Technologies State Corporation and a former head of the Russian space agency, is chairing an investigation into the failure. The findings are due to be made public on 26 January, and are sure to undergo tough scrutiny. The issue became politically charged when the Russian president, Dmitry Medvedev, told reporters in late November that financial, disciplinary or even criminal charges could be used to punish those found responsible for space mishaps. Meanwhile, tracking teams are still working to pinpoint whether Phobos-Grunt hit the surface, and if so, where

http://www.newscientist.com/.

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