Stranded Mars probe sends further signals

Thursday, November 24th 2011. | Science News

More attempts have been made by the European Space Agency (Esa) to contact the stricken Russian probe Phobos-Grunt – with partial success.

Stranded Mars probe sends further signalsCommunication with the craft as it passed over Australia was achieved again on Thursday, but not all of the commands prompted a response.

Phobos-Grunt was launched two weeks ago on a mission to visit one of Mars’ moons, but became stuck in Earth orbit.

Engineers still hope to fix the probe and get the mission under way.

But first they need to be able to talk with it. Europe’s 15m dish in Perth was the first to successfully make contact with the spacecraft in a fortnight of trying by tracking stations around the globe.

Esa modified the antenna to widen its beam, and also reduced the power of the transmission to match the type of X-band signal Phobos-Grunt would have expected to see nearer the Red Planet.

On Wednesday, those modifications prompted the probe to switch on its transmitter and send down some basic telemetry. On Thursday, a further five efforts were made to contact the spacecraft, with the first at 0420 local time (2020 GMT, Wednesday) also initiating a stream of data from Phobos-Grunt.

But the next four passes saw nothing come back down. The second attempt was not expected to yield data, but the final three passes certainly were.

The situation is now being assessed by engineers at the probe’s Russian manufacturer, NPO Lavochkin. Esa says it stands ready to help in any way, and will continue to work with Russian engineers as they try to diagnose the mission’s problems and find a solution.

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