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European comet lander Philae dropped into a hole about its own size just one metre from a towering cliff, scientists said.
Newly-published data from the mission show that the craft was also surrounded by boulders up to a metre wide and came to rest with one of its three feet pointing up.
Standing in partial shadow, the washing machine-sized probe was unable to keep itself warm or generate sufficient electricity from its solar panels, and shut down.
In June scientists announced that the craft had woken up from hibernation seven months after bouncing dramatically on to the surface of comet 67P/Churyumov-Gerasimenko.
More light was thought to be reaching its solar panels as the comet travelled closer to the sun.
Experts analysing a wealth of information from Philae have reported some of their first results in the latest issue of the journal Science.
The probe was surrounded by boulders
One paper, based on analysis of images taken by the probe’s seven cameras, provides more detail about what happened when the craft landed after leaving the orbiting Rosetta mothership on November 12.
Others describe organic compounds detected by Philae, including four never before identified on a comet, but nothing clearly defined as a building block of life.
Philae did not stay long at its intended landing site, a soft granular surface about 30cm deep with a harder layer below. Instead it bounced twice, finally coming to rest in a different location more than half a mile away.
The image team, led by Jean-Pierre Bibring, from the Université Paris-Sud in France, described how Philae seemed to be “in a hole about its own size, partially shadowed by nearby boulders or cliffs”.
One foot was probably stuck in a “local cavity”, another rested on a sunlit surface, and the third was “pointing upward”.
The researchers added: “The landing site is dominated by metre-scale blocks, with a large elongated cliff, starting around one metre away. These large structures are responsible for Philae being partially shadowed, drastically limiting its energy intake for both warming up the internal compartment and supplying the solar panels.”
German-led scientists in charge of an instrument called Cosac (Cometary Sampling and Composition) reported the collection of organic molecules from nine kilometes above the comet’s surface, after initial touchdown, and at the final landing site.
They detected 16 organic compounds, four of which – methyl isocyanate, acetone, propionaldehyde and acetamide – were previously unknown to exist on comets. A shoe-box sized gas-sniffing instrument called Ptolemy, operated by a British team led by Ian Wright, from the Open University, also analysed organic compounds.
It indicated the presence of a polyoxymethylene (POM), an organic polymer, or chained compound, on the comet surface. POM has been suggested as playing a key role in prebiotic chemistry.