European space engineers are hoping to carry out carefully programmed manoeuvres over the coming hours and days to rescue the Philae lander from its precarious position on the comet 67P/Churyumov-Gerasimenko after it unexpectedly bounced twice on landing.
The fridge-size lander is standing on two of its three legs, and its solar panels are sitting in the shadow of a nearby cliff face forming the edge of a large crater where Philae was supposed to have made a soft touch-down on the comet, the European Space Agency (ESA) said.
The orbiting Rosetta spacecraft was tonight trying to work out exactly where its Philae lander is located. ESA scientists calculated that Philae’s first bounce, lasting nearly two hours, carried it about a kilometre away from the original point of contact while the second smaller bounce lasted for about seven minutes, carrying it several metres further.
It finally came to rest under the influence to the comet’s exceptionally low gravity, which is just one hundred-thousandth of the Earth’s gravitational force, meaning that the lander weighs about a gram on the comet.
Two harpoons were meant to anchor Philae to the frozen surface but both failed to fire, ESA said. Ice screws on its legs may also have failed to work. The shade of the cliff face means that the solar panels, which should be recharging the lander’s secondary batteries, are receiving only about 1.5 hours of sunlight compared with the scheduled six or seven hours of recharging time.
The primary batteries are expected to run out of power within the next two to three days as Philae had enough on-board battery power to last about 64 hours from the time of landing. Ground engineers are analysing whether it might be possible to adjust its solar panels, which are wrapped around the lander’s body, to extend Philae’s working life.
Almost all of Philae’s instruments are working well and ESA scientists said that the Rosetta mission has already accumulated more data on a single comet than any previous space mission, despite the less-than-perfect landing.
In pictures: European Space Agency's Rosetta mission
In pictures: European Space Agency's Rosetta mission
1/22 European Space Agency's Rosetta mission
Image of Comet 67P/CG taken by the Philae lander from a distance of approximately 3km from the surface
2/22 European Space Agency's Rosetta mission
Rosetta's lander Philae took this parting shot of its mothership shortly after separation
3/22 European Space Agency's Rosetta mission
Parting shot of the Philae lander after separation, captured by one of Rosetta's cameras
4/22 European Space Agency's Rosetta mission
A technician celebrates after the successful landing of the Philae lander, in the control room at the ESA headquarters in Darmstadt
5/22 European Space Agency's Rosetta mission
Scientists celebrate at a mission observation centre in Toulouse, southern France as they receive information that Philae has landed on the Churyumov-Gerasimenko comet
6/22 European Space Agency's Rosetta mission
Astronomer Klim Ivanovych Churyumov, who discovered the comet 67P/ Churyumov-Gerasimenko in 1969, reacts after the successful landing of the Philae lander on the comet
7/22 European Space Agency's Rosetta mission
A model demonstrates how the landing device Philae, of the space probe Rosetta, stands on the comet 67P/Churyumov-Gerasimenko at the press center of the satellite control center of the European Space Agency in Darmstadt, Germany
8/22 European Space Agency's Rosetta mission
An artist impression of Rosetta's lander Philae on the surface of comet
9/22 European Space Agency's Rosetta mission
Picture taken on October 28 by the navigation camera on Rosetta shows the boulder-strewn neck region of comet 67/P Churyumov-Gerasimenko. It was captured from a distance of 9.7 km from the center of the comet
10/22 European Space Agency's Rosetta mission
Picture taken on October 24 shows a raised plateau on the larger lobe of the comet
11/22 European Space Agency's Rosetta mission
The probe is supposed to fly to a comet and put down a small laboratory on the top of it
12/22 European Space Agency's Rosetta mission
A scientist from the European Space Agency with an airworthy copy of space probe 'Rosetta' in the control center in Darmstadt, Germany
13/22 European Space Agency's Rosetta mission
Maneuvers designed for the actual space probe are simulated with the replica. 'Rosetta' will be woken up from an energy saving hibernation after 957 days
14/22 European Space Agency's Rosetta mission
A European Space Agency employee sits in the control room for the Rosetta mission in Darmstadt, Germany
15/22 European Space Agency's Rosetta mission
Scientists at the European Space Agency are expecting their comet-chasing probe Rosetta to wake from almost three years of hibernation
16/22 European Space Agency's Rosetta mission
Europe's Rosetta probe on a NASA mission
17/22 European Space Agency's Rosetta mission
NASA is participating in the European Space Agency's Rosetta mission, whose goal is to observe one such space-bound icy dirt ball from up close for months on end
18/22 European Space Agency's Rosetta mission
An impression of the Philae lander
19/22 European Space Agency's Rosetta mission
ESA probe Rosetta with Mars in the background. The three-tonne probe blasted off aboard an an Ariane V rocket from Kourou, French Guiana in 2004
20/22 European Space Agency's Rosetta mission
Rosetta orbiter deploying the Philae lander to comet 67P/Churyumov–Gerasimenko, the spacecraft measures 32 m across including the solar arrays, while the comet nucleus is thought to be about 4 km wide
21/22 European Space Agency's Rosetta mission
The spacecraft, festooned with 25 instruments between its lander and orbiter (including three from NASA), is programmed to 'wake up' from hibernation
22/22 European Space Agency's Rosetta mission
An Ariane V carrying the three-tonne probe Rosetta blasting off from Kourou, beginning a decade-long quest to hunt a comet in the depths of the Solar System and shadow it around the Sun in a bid to tease out secrets of how life began on Earth
However, the precarious landing means that a plan to drill into the comet may have to be postponed indefinitely because of the risk of destabilising the lander.
Rosetta is the first mission to orbit a comet and the first to land a robotic probe on its icy surface. It took 10 years since its launch in 2004 for Rosetta to travel to comet 67/P, which currently 510m km (311m miles) from Earth in the direction of the constellation Sagittarius.
“Do not have the impression this is a failure. What is really amazing is not the degree of failure but the degree of success. It’s gorgeous where we are,” said Professor Jean-Pierre Bibring, the lead landing scientist on Rosetta.
“We are just in the shadow of a cliff. We are in a shadow permanently, and that is part of the problem,” Professor Bibring said from ESA’s mission control in Darmstadt, Germany.
READ MORE: WHY DID PHILAE BOUNCE?
Professor's reaction is a scientifically accurate picture of joy
Philae sends back first ever image from comet 67P
“We're almost vertical. One foot probably is in open space and two feet are on the surface. It could be that we are somewhere in the rim of this crater, which could explain this bizarre orientation,” he said pointing to an image of the landing crater on the comet’s smaller lobe.
“[Still] many of the other instruments have already acquired what they wanted to. A lot of science is getting covered now. We might try to better orientate the solar panels,” he added.
If the solar panels were working at full throttle, the Philae lander could still be collecting and transmitting data through to next March, when the surface temperatures are expected to become too high for its instruments to function.
It may still be possible to perform some manoeuvres that could bounce the lander back into the sunlight, but ESA is unlikely to take this risk unless there is nothing to lose in terms of gathering further data.
It is also possible that as the comet moves closer to the Sun, and angle of sunlight might change, bringing Philae out of the shadow. If this happens, the batteries, which are designed to go into “hibernation”, might start to recharge themselves and so trigger a second contact with the Rosetta mothership overhead.
But even if the Philae lander runs out of power within the next few days, the Rosetta spacecraft will continue to orbit the comet as it makes its closest approach to the Sun, sending back images and data for another 12 months, ESA said.
What has Philae found so far?
Masses of information has already been gathered on the comet 67/P and the data could help to solve some of the biggest questions in space, such as whether comets could have brought water and the simple organic building blocks of life to the early Earth.
“Rosetta is trying to answer the very big questions about the history of our Solar System. What were the conditions like at its infancy and how did it evolve? What role did comets play in this evolution? How do comets work?” said Matt Taylor, the London-born project scientist on Rosetta.
While the Philae lander gathers data from the surface of the comet, the orbiting Rosetta mother-ship will collect information and images from above – for the next 12 months as the comet makes its closest approach to the Sun.
The lander has already measured the electrical, mechanical and magnetic properties of the surface and is probing the comet’s internal structure with low-frequency signals sent to Rosetta when it dips below the horizon.Reuse content