Rosetta mission's landing site on comet 67P may lead to power problems

The first spacecraft ever to land on a comet appears to have come to rest in the shadow of a cliff, posing a potential problem for its solar panels.

Philae lander scored a historic first, when it touched down on comet 67P/Churyumov-Gerasimenko

Rosetta lander's problematic position on comet

9 years ago
Duration 3:17
Lander scored a historic first when it bounced twice and grabbed on to comet, but on the edge of a hole
  Europe's comet lander  Philae has come to rest in the shadow of a cliff, posing a potential problem for its solar panels, scientists from the European Space Agency said Thursday as they published the first image from the surface of a comet.

The photo shows a rocky terrain, with one of the lander's three feet in the corner of the frame. It is part of a slew of data that Philae is transmitting back to Earth, indicating that its instruments are working properly, said Jean-Pierre Bibring, the lander's lead scientist at the European Space Agency.

Philae took this panoramic view of the rocky black terrain around it on Comet 67P. (ESA)

Before deciding whether to try to adjust the lander, scientists will spend the next day or two collecting as much data as possible while its primary battery still has energy. The lander's solar panels were designed to provide an extra hour of battery life each day after that, but this may not be possible now.

"We see that we get less solar power than we planned for," said Koen Geurts of the lander team.

"This, of course, has an impact on our energy budget and our capabilities to conduct science for an extended period of time," he said. "Unfortunately this is not a situation that we were hoping for."

The lander scored a historic first Wednesday, touching down on comet 67P/Churyumov-Gerasimenko after a decade-long, 6.4-billion kilometre journey through space aboard its mother ship, Rosetta. The comet is streaking through space at 66,000 km/h some 500 million kilometres from Earth.

The landing was beset by a series of problems that began when thrusters meant to push Philae onto the comet failed. Then two harpoons, which should have anchored the lander to the surface, weren't deployed.

Philae first landed near the red square, the original planned site, then bounced and is now thought to be somewhere in the blue diamond, said ESA's Stephan Ulamec at a news conference Thursday. (ESA)

This caused the lander to bounce off the comet and drift through the void for two hours before touching down again. After a second smaller bounce, scientists believe it came to rest in a shallow crater on the comet's four kilometre-wide body, or nucleus.

"We are just in the shadow of a cliff," Bibring said, adding that photos indicate the cliff could be just a few yards (metres) away. "We are in a shadow permanently, and that is part of the problem."

Bibring and his colleagues stressed that the data they'll be able to collect with the primary batteries alone will have made the landing worthwhile.

"A lot of science is getting covered now," he said, noting that scientists would soon get their hands on a tomography of the comet and data showing whether the matter it is made of is magnetized.

Drilling delayed

But because the lander is just resting on the comet with nothing but low gravity holding it down, Philae will have to hold off on one of the most important experiments — drilling into the comet to extract some of the material buried beneath the surface.

Scientists want to analyze this material because it has remained almost unchanged for 4.5 billion years, making them cosmic time capsules.

"Drilling without being anchored and without knowing how you are on the surface is dangerous. We might just tip over the lander," said Stephan Ulamec, head of the lander operation. Gravity on the comet is 1/100,000th that of Earth, meaning the 100-kilogram, washing machine-sized lander weighs only as much on the comet as a gram does on Earth.

Ground controllers will likely wait until the first big batch of data has been collected before attempting to adjust the lander so that its solar panels can catch the sun and charge its batteries.

Communication with the lander is slow, with signals taking more than 28 minutes to travel between Earth and the Rosetta orbiter flying above the comet.

During a news conference, the European Space Agency showed a series of photos taken by Philae of the black cliffs and rocky terrain around it . Bibring said researchers had expected Philae to land on a powdery material. 

"It's not a powder," he said. "It's like a rock."

Jakub Urbanek, a Canadian from Windsor, Ont., who works as an operations engineer on the Rosetta team, called the photos from the comet's surface "absolutely stunning."

"The detail that we can see is just amazing," he said in an interview with CBC News.

Even if Philae uses up all of its energy, it will remain on the comet in a mode of hibernation for the coming months. In theory it could wake up again if the comet passes the sun in such a way that the solar panels catch more light, said Ulamec.

Meanwhile the orbiter, Rosetta, will also use its 11 instruments to analyze the comet over the coming months. Scientists hope the 1.3 billion euro ($1.8 billion) project will help them better understand comets and other celestial objects, as well as possibly answer questions about the origins of life on Earth.

With a file from CBC News