ESA gives up on duff Russian Mars probe Phobos-Grunt
Russians vow to keep trying until it comes down burning
The European Space Agency has abandoned attempts to revive dud Martian probe Phobos-Grunt after days of trying to contact the clapped-out craft with no success.
The agency, along with Russian space boffins at Roscosmos, has been trying to send commands to the craft to get it to raise its Earth orbit - but Phobos-Grunt has neither lifted nor responded to the orders, said Manfred Warhaut, head of mission operations, in a conference call with reporters including the Reg this afternoon.
If the probe could lift its orbit, it could stay circling our planet for longer and extend the window of opportunity for ground stations to contact it.
Initially, the ESA was sending 'time-tagged' orders – commands that are sent up now but are to be acted on at a specific and opportune time in the future, which Warhaut described as "fishing in the dark".
"[For time-tagged commands] you have to know the onboard time and you have to know that the onboard systems are on," he said.
The probe has been orbiting Earth since its engines failed to send it off to Mars on 9 November; after attempts to tell the craft to activate its thrusters, engineers can't tell whether the probe simply hadn't heard the instructions or that it just couldn't manage the shift.
The agency started sending direct command requests for Phobos-Grunt to turn its transmitter on and send telemetry as well, which would have been answered straight away, but these also failed to elicit a response.
Warhaut said that the ESA was giving up on contacting the probe for now, but would be on hand to aid the Russians if they managed to get back in touch with Phobos-Grunt.
"We are not in a position to continue," he said, pointing out that the ESA had its own missions for which it needed its engineers. But he said that the Russian space agency, Roscosmos, confirmed that it wasn't going to give up on Phobos-Grunt.
"They will try to send some thruster commands in direct mode," he said. Warhaut added that the Russians will attempt to perfect the sending of command signals with a simulator before firing them at the probe.
Since the ESA first made brief albeit garbled contact with the probe on 23 November from its Perth station, the agency and Roscosmos have been trying every method at their disposal to stay in touch with it. This week, the ESA also made modifications at its Maspalomas station in the Canaries to try to hail the ship from there.
However, they have now exhausted all the technical options for contact, Warhaut said. Trying to transmit at a higher power would only damage the craft, he added. For now, Phobos-Grunt is in a low orbit, with a perigee of about 200km and an apogee of about 340km above the Earth, and its direction is stable, but it is gradually descending.
Warhaut said there was a "high degree of uncertainty" about when the probe would fall into the atmosphere, assuming it can't be contacted, but he echoed comments from the Russians that the fuel tanks at least would disintegrate and burn up on re-entry.
Vladimir Popovkin, head of Roscosmos, has previously said that the fuel tanks exploding will vaporise the rest of the craft, leaving only negligible bits to fall to Earth. ®
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