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| Version 3 | Version 4 |
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| Rosetta: Comet probe Philae now stable - scientists | Rosetta: Comet probe Philae now stable - scientists |
| (35 minutes later) | |
| The robot probe Philae that made a historic comet landing is now stable after initially failing to attach to the surface, and is sending pictures. | The robot probe Philae that made a historic comet landing is now stable after initially failing to attach to the surface, and is sending pictures. |
| Efforts are now being made to locate the precise position of the European Space Agency probe on the comet. | Efforts are now being made to locate the precise position of the European Space Agency probe on the comet. |
| Engineers say it may have bounced hundreds of metres back off the surface after first touching down. | Engineers say it may have bounced hundreds of metres back off the surface after first touching down. |
| Scientists hope the probe will analyse the comet's surface to yield insights into the origins of our Solar System. | Scientists hope the probe will analyse the comet's surface to yield insights into the origins of our Solar System. |
| The Esa's Rosetta satellite carried Philae on a 6.4 billion-km (4bn-mile) journey to Comet 67P/Churyumov-Gerasimenko. | The Esa's Rosetta satellite carried Philae on a 6.4 billion-km (4bn-mile) journey to Comet 67P/Churyumov-Gerasimenko. |
| The robot probe, the size of a washing machine, was dropped from the satellite on Wednesday and spent seven hours travelling down to the icy body. | The robot probe, the size of a washing machine, was dropped from the satellite on Wednesday and spent seven hours travelling down to the icy body. |
| News of the "first" landing was confirmed at about 16:05 GMT. | News of the "first" landing was confirmed at about 16:05 GMT. |
| Facts are still being established but this is the current best guess for how events unfolded | |
| Ebullient mood | Ebullient mood |
| Controllers re-established radio communication with the probe on cue on Thursday after a scheduled break, and are retrieving pictures from it. | Controllers re-established radio communication with the probe on cue on Thursday after a scheduled break, and are retrieving pictures from it. |
| These show the feet of the lander and the wider cometscape. | These show the feet of the lander and the wider cometscape. |
| But there is still concern about the longer-term stability of Philae because it is not properly anchored - the harpoons that should have hooked it into the surface did not fire on contact. Neither did its feet screws get any purchase. | But there is still concern about the longer-term stability of Philae because it is not properly anchored - the harpoons that should have hooked it into the surface did not fire on contact. Neither did its feet screws get any purchase. |
| Mission facts: | Mission facts: |
| Philae lander | Philae lander |
| Comet 67P | Comet 67P |
| Can you land on a comet? | Can you land on a comet? |
| 'More black swan than yellow duck' | 'More black swan than yellow duck' |
| Brief encounters with comets | Brief encounters with comets |
| Lander project manager Stephan Ulamec told the BBC that he was very wary of now commanding the harpoons to fire, as this could throw Philae back off into space. | Lander project manager Stephan Ulamec told the BBC that he was very wary of now commanding the harpoons to fire, as this could throw Philae back off into space. |
| He also has worries about drilling into the comet because this too could affect the stability of the lander. | He also has worries about drilling into the comet because this too could affect the stability of the lander. |
| "We are still not anchored," he said. "We are sitting with the weight of the lander somehow on the comet. We are pretty sure where we landed the first time, and then we made quite a leap. Some people say it is in the order of 1 km high. | "We are still not anchored," he said. "We are sitting with the weight of the lander somehow on the comet. We are pretty sure where we landed the first time, and then we made quite a leap. Some people say it is in the order of 1 km high. |
| "And then we had another small leap, and now we are sitting there, and transmitting, and everything else is something we have to start understanding and keep interpreting." | "And then we had another small leap, and now we are sitting there, and transmitting, and everything else is something we have to start understanding and keep interpreting." |
| The mood at Esa's operations centre in Darmstadt, Germany, this morning is very ebullient following the historic touchdown. | The mood at Esa's operations centre in Darmstadt, Germany, this morning is very ebullient following the historic touchdown. |
| When it became clear just after landing that the contact was not clean, there was considerable worry. That has changed noticeably. | |
| Holger Sierks, the principal investigator of the science cameras on Philae's mothership, Rosetta, which is circling the comet overhead, said his team was now trying to take pictures of the robot on the surface. | Holger Sierks, the principal investigator of the science cameras on Philae's mothership, Rosetta, which is circling the comet overhead, said his team was now trying to take pictures of the robot on the surface. |
| These pictures will show very little detail because Rosetta is many tens of kilometres away, but they will help controllers understand where the probe came to rest after its bouncing. | |
| If the probe remains stable, it will engage in several months of science experiments on 67P. | If the probe remains stable, it will engage in several months of science experiments on 67P. |
| It will take pictures of the cometscape and analyse the surface chemical composition to test several hypotheses about the origins of life and the universe. | It will take pictures of the cometscape and analyse the surface chemical composition to test several hypotheses about the origins of life and the universe. |
| One theory holds that comets were responsible for delivering water to the planets. Another idea is that they could have "seeded" the Earth with the chemistry needed to help kick-start life. | One theory holds that comets were responsible for delivering water to the planets. Another idea is that they could have "seeded" the Earth with the chemistry needed to help kick-start life. |