Scientists at the European Space Agency (ESA) are facing anxious moments as they wait for data to be sent back from the Philae lander.
The craft should be sending data back from the surface of the comet it started drilling on earlier.
But Philae is also facing an energy problem.
It needs more sunlight to power its solar panels, meaning the ESA team may try to 'hop' it into a more favourable position.
ITV News Science Correspondent Alok Jha reports.
Comet probe Philae has started drilling into the surface of the comet which it landed on this Wednesday.
But there may not be enough power left in the craft's depleting batteries to obtain scientific data from the samples it collects.
Philae is believed to be tilted to one side in the shadow of a crater wall and is not getting enough light to recharge its batteries using electricity generated by its solar panels.
With less than 24 hours before the craft's primary battery power runs out, scientists are actively considering taking a last-ditch gamble and "hopping" the lander to a sunnier spot. Read: Scientists debating whether to 'hop' Philae to new spot
A British scientist working on the Rosetta project has apologised for his choice of shirt after a backlash on social media.
Dr Matt Taylor was initially hailed as ‘cool’ for his colourful choice of shirt, which showed off his full sleeve tattoos. But a closer look revealed the pattern on the clothing was made up of scantily-clad women, leading to accusations that it was sexist.
In a Google Hangout briefing on the latest developments in the project today, Dr Taylor appeared to be fighting back tears as he apologised. His colleague, flight director Andrea Accomazzo, even gave him a comforting pat on the shoulder as he composed himself.
The shirt I wore this week – I made a big mistake, and I offended many people, and I’m very sorry about this.
Scientists racing against time to keep the Philae comet lander operating are debating whether to try 'hopping' the probe to a new location.Read the full story ›
The scientists behind the Philae comet lander have Tweeted to confirm they have reestablished contact with probe.
There has been concern that because the probe had landed in the shadow of a cliff, the solar panels designed to recharge the probe's batteries would not work. It is feared the probe could run out of life by tomorrow afternoon.
However, there was some good news as the team confirmed they had been able to hammer the multi-purpose sensor (MUPUS) penetrator into the ground, while a special X-ray (APXS) also began to work.
They will now start to collect samples from the surface and within the comet for analysis.
The space probe that made history by landing on a comet 300 million miles from earth has achieved another extraordinary first by sending back photographs from the comet's surface.
But concerns grew over the exact place the probe eventually landed.
Philae is tucked up under the shadow of a huge ledge so scientists may find it difficult to re-charge its batteries.
Much of the probe's work is done but sorting out the solar panels is now the priority.
ITV News science correspondent Alok Jha has the latest from mission control in Germany:
After the first man-made craft landed on a moving comet we look at the pictures sent back from the daring descent to the historic landing.Read the full story ›
The first panoramic image taken by the lander of its surroundings has been released.
The image will help scientists find out where the Philae Lander is and how it is resting on the surface of the comet.
The Royal Mail will celebrate the landing of a spacecraft on a comet with a special postmark on millions of items of mail delivered to addresses nationwide on Friday and Saturday.
It will say: Celebrating the first ever landing on a comet. Congratulations to the European Space Agency.
We're thrilled to be marking the European Space Agency's fantastic achievement with one of our special postmarks.
Our postmark is set to take off and will appear on mail delivered by our postmen and women across the UK.
Three images, taken an hour apart, show the descent of the Philae Lander as it headed for its rendezvous with the Comet 67P/Churyumov-Gerasimenko.
The lander can be seen turning gently as it slowly chased the comet.
Click on the link above to view the images together.