Rosetta's Philae lander sends last-gasp data before 'going to sleep'

Robot probe Philae has sent a last minute data to Earth before it ran out of batteries on the comet.

Rosetta's Philae lander sends last-gasp data before 'going to sleep'
ESA/Rosetta/Philae/CIVA

Zee Media Bureau

Paris: Robot probe Philae has sent a last minute data to Earth before it ran out of batteries on the comet.

Data streamed in as soon as Europe's pioneering robot lab re-established late-night contact with its orbiting mothership, Rosetta, but its limited battery soon started wavering as it couldn't get into sunlight even after several attempts.

Philae was receiving just 1.5 hours of sunlight instead of the expected 6-7 hours.

"My #lifeonacomet has just begun," said an official tweet in the name of the washing machine-sized lander perched on comet 67P/Churyumov-Gerasimenko since Wednesday -- concluding with a restful "zzzzz".

"S'ok Philae, I've got it from here for now. Rest well...," said a response tweeted on behalf of Rosetta.

The European Space Agency (ESA) said its robot lab had entered "idle mode", with all instruments and most systems shut down after three days of non-stop work -- taking pictures and probing the comet's density, temperature, composition and atmosphere.

"Prior to falling silent, the lander was able to transmit all science data gathered," said a statement.

The lander and its mothership, which relayed Philae's data to Earth, had only two communications windows per day -- the last opened around 0300 IST yesterday and closed at 0606 IST the next morning as Rosetta disappeared in orbit behind the comet.

Mission controllers had feared the robot may not even have enough power to make contact during this window -- but they were pleasantly surprised.

"Science from an alien world" ESA Operations tweeted when contact was made. "Info now flowing from @ Philae2014."

The channel should open again around 0630 IST today, but lander manager Stephan Ulamec told AFP from mission control in Darmstadt, Germany, he did "not really expect" contact with Philae then.

"The chances that we could reestablish the link again tomorrow are really very, very low," he said.

"The battery is not completely empty, but it is below the level the central computer needs to boot" up.

In one of many jaw-dropping achievements, the robot lab appears to have lifted itself slightly yesterday and rotate the larger of its solar panels to absorb as much energy as possible to be stored for a possible wakeup later.

Philae had landed in a dark ditch after a bouncy touchdown Wednesday, and did not get enough sunlight to recharge its batteries sufficiently to extend its mission.

Philae's primary mission was always designed to last around 60 hours on its initial battery charge but engineers covered the spacecraft in solar panels in the hope that sunlight could charge a set of secondary batteries and extend the mission for months.

Philae's historic on-site survey of a comet travelling at 18 kilometres per second, currently at a distance of 510 million kilometres from Earth, is the highlight in a more than decade-long mission.

Philae landed Wednesday after a nail-biting seven-hour, 20-km descent from Rosetta, which had travelled more than a decade and 6.5 billion kilometres to meet up with the comet in August this year.

(With Agency inputs)