The European spacecraft that landed on a comet in a historic mission earlier this week has carried out two tricky maneuvers, by drilling into the rocky surface and rotating itself to catch more sunlight.

Both operations carried considerable risks, because they could have toppled the probe or pushed it out into the void, but scientists at the European Space Agency said the maneuvers appeared to have worked.

My rotation was successful (35 degrees). Looks like a whole new comet from this angle.

Philae lander Twitter account

Since landing on comet 67P/Churyumov-Gerasimenko about 500 million kilometres away, the lander has performed a series of tests and sent reams of data, including photos, back to Earth.

But with just two or three days of power in its primary battery, the lander now has to rely on solar panels to generate electricity.

The European Space Agency said the lander, which has fallen asleep on with its batteries depleted and not enough sunlight available, may communicate again on Saturday at about 10:00 GMT.

"From now on no contact would be possible unless sufficient sunlight falls on the solar panels to generate enough power to wake it up," ESA wrote on its blog early Saturday.

Idle mode

"My rotation was successful (35 degrees). Looks like a whole new comet from this angle,'' read a message posted on the lander's official Twitter account.

Earlier, the scientists tweeted : "First comet drilling is a fact!'' 

The space agency said late on Friday that the batteries eventually depleted and without enough sunlight to recharge them, Philae fell into "idle mode", and all instruments and most of the systems on board shut down. 

However, "Prior to falling silent, the lander was able to transmit all science data gathered during the First Science Sequence," said Stephan Ulamec, lander manager.

Scientists were concerned to find on Thursday that not only had Philae unexpectedly bounced twice before coming to rest untethered to the surface, but photos indicated it was next to a cliff that largely blocked sunlight from reaching two of its three solar panels.

With time running out, scientists decided to risk moving the lander and performing one of the most important experiments it was sent into space for.

Researching universe origins

Material beneath the surface of the comet has remained almost unchanged for 4.5 billion years, making the mining samples a cosmic time capsule that scientists are eager to study.

Mission controllers said Philae was able to bore 25 centimetres into the comet to start collecting the samples, but it is unclear whether it has enough power to deliver any information on them.

It also was not immediately clear whether the rotation had succeeded in putting the lander's solar panels out of the shadow. Scientists are likely to know for sure early on Saturday.

Meanwhile, the Rosetta, Philae's mother ship, which is streaking through space in tandem with the comet will use its 11 instruments to analyse the comet over the coming months.

Scientists hope the $1.6b project that was launched a decade ago will help them answer questions about the origins of the universe and life on Earth.

Source: Agencies