Engine Trouble Leaves Russian Phobos Probe Stranded in Orbit

Daniel is a deputy news editor for Science.

Russia's first solar system exploration mission since 1996 hangs in the balance today as the probe failed to ignite its engines to start the journey to Mars.

The mission is an ambitious attempt to return samples from Mars's moon Phobos. Following a perfect launch during the night from the Baikonur Cosmodrome in Kazakhstan on a Russian Zenit rocket, the Phobos-Grunt probe (grunt is Russian for soil) was placed into Earth orbit. Then there was a conspicuous silence from Russian space authorities, according to the Web site RussianSpaceWeb, until several hours later when reports said there were problems with Phobos-Grunt's main propulsion unit (MDU) which would propel it all the way to Mars.

"It has been a tough night for us because we could not detect the spacecraft [after the separation]," Vladimir Popovkin, head of the Russian Federal Space Agency told the RIA Novosti news agency. "Now we know its coordinates and we found out that the [probe's] engine failed to start."

Popovkin suggested that software was to blame and said that this sort of contingency had been prepared for. He said engineers were working to reboot the craft's control system and then there would be another attempt to send the command to fire the engines. He said that they had three days to sort out the problem before batteries ran out of power, suggesting that the control system was also not steering solar panels towards the sun to charge the batteries.

"We've had significant help from U.S. military providing the exact coordinates of spacecraft at this intermediate orbit. We will try to send commands to spacecraft tonight when there will be radiovisibility from Russian stations," says Lev Zelenyi, director of the Institute of Space Research (IKI) in Moscow which developed the mission. "So I still have some hope. We still have a few days for reprogramming before the end of the Mars accessibility window for 2011."

The spacecraft was designed to make a soft landing onto the surface of Mars's potato-shaped moon. It carries 20 instruments with contributions from European countries and the United States. Also on board is a Chinese Mars orbiter, Yinghuo-1, which was due to be released before the descent onto Phobos. This is China's first mission to Mars.

Once on Phobos, the instruments will study soil samples in situ as well as surveying the atmosphere and environment of Mars from their orbiting vantage point. It is thought that the surface of Phobos contains material from the surface of Mars that were thrown up by meteorite impacts. After about a week of soil sampling, a small return capsule with up to 160 grams of soil on board will be launched by springs (possible because of the moon's weak gravity). Once it is some kilometers away it will fire its own engines for the 11-month journey back to Earth.

Phobos-Grunt was first proposed in 1996 but at that time the Russian economy was in turmoil and there was little money for space exploration. It remained a paper project until the middle of the past decade when it was given high priority by the Russian Academy of Sciences and began to receive more government funding. The mission was slated for launch in late 2009 and, despite numerous delays and late-delivered components, the Russian Space Agency insisted it was on schedule until just a couple of months before the launch date. Some suspect the agency was holding onto the date for political or funding reasons.

With the pressure off, scientific instruments and other hardware were removed and taken back by their developers for upgrades and extra testing. Even Yinghuo-1 was sent back to China. There was also more time for thorough testing of the onboard flight control system which was new, having been developed from scratch by the craft's builder, NPO Lavochkin, rather than supplied by the usual contractor for such work. Lavochkin also commissioned a new drill system from Poland in case the surface of Phobos was rocky and the soil sample arm was unable to penetrate.

Posted in Space, Europe