00:05This is the moment we made history by landing on a comet.
00:11Ten years ago, our Rosetta mission got up close and personal with a comet,
00:17landing a probe called Philae on the surface to directly study the properties of a comet for the first time
00:24ever.
00:26The mission was groundbreaking. It was only the seventh celestial object we have landed on before.
00:33It was an ambitious journey filled with many ups and downs.
00:37But we're getting ahead of ourselves. Let's take a look back at the mission ten years on.
00:52Comets are large objects made of dust and ice that have elliptical orbits around the sun,
00:58which stretch far out into the outer edges of the solar system.
01:03They are believed to be left over from when the planets formed,
01:06and scientists think they could hold the answers to how life formed on Earth,
01:11why we have water on Earth, and how the solar system evolved.
01:17You may recognise comets from their distinctive bright tail,
01:21caused by the sun heating up the frozen comet core as they head towards the inner solar system,
01:28leaving behind this bright streak of dust and gas.
01:32Most comets are too small and far away to see from Earth, even with some of the biggest telescopes.
01:38And when they do come close, their bright tail obscures our view of the actual comet itself,
01:45making it hard to see and study from Earth.
01:49That's where our Rosetta mission comes in.
02:00Rosetta was launched in March 2004 on one of our Ariane 5 rockets.
02:05From here, it set off on its ten-year-long journey to Comet 67P, Duryumov-Gerasimenko.
02:14The comet was chosen as it originated in the Cowper Belt,
02:17but does not venture out much farther than Jupiter anymore,
02:21making it perfect to align with Rosetta's journey.
02:24However, the journey was anything but simple.
02:29Rosetta required some energy boosts along the way,
02:32starting with the gravity assist of Earth, just a year after launch,
02:36which sent the spacecraft on towards Mars for another boost.
02:40From here, Rosetta came back to Earth before passing by the diamond-shaped asteroid Steinez.
02:48And returning back to Earth for one final boost.
02:51Rosetta then got on its way to deeper space,
02:54flying past the huge ancient rock Letizia, grabbing photos and data along the way.
03:01After all of this excitement, as Rosetta travelled on farther from the Sun,
03:06it did not have enough solar power to operate fully.
03:10So was put into standby mode, sending the spacecraft into a two-year, seven-month and twelve-day slumber.
03:18In January 2014, the world sent Rosetta a wake-up call,
03:23and the team got sent to work to make sure all the instruments on board were working after the long
03:29break.
03:31The spacecraft still had ten more manoeuvres to perform to align it correctly with the comet,
03:37and to get it to the right speed so it would be captured by the comet's gravity and not be
03:42flung off into space.
03:51As Rosetta approached Comet 67P, scientists spotted something unusual.
03:57The team expected to see that the central part of the comet, its nucleus,
04:02is sort of shaped like a potato, but instead, the images Rosetta sent back resembled more of a rubber duck
04:10shape.
04:10It had two lobes, almost as if the two comets had slammed into each other and bonded.
04:17It looked like nothing we had ever examined in the solar system before.
04:22This made landing Feely a bit more complicated.
04:26The complex shape of the comet made for a complex gravity and a strange rotation situation,
04:33which made flying around it very complicated.
04:36There were also craters, cliffs, sinkholes and boulders the size of houses, which had to be taken into account.
04:45Rosetta spent a few weeks analysing the comet, sending back information so the experts could determine where was best to
04:52land.
04:53Typically landing sites, for example on Mars, take years to select, so for Feely it happened exceptionally fast.
05:02No lander had attempted to make a soft landing on a comet before, so there was a lot at stake.
05:09Finally, the experts decided on the perfect landing spot for Feely, and the probe was sent down,
05:16and the world held its breath for seven hours to hear if the spacecraft landed successfully.
05:23Touchdown was confirmed at 1703 Central European Time on the 12th of November.
05:30But there was something strange about the data returned.
05:34Soon scientists, flight dynamics specialists and engineers concluded that Feely did not just touch down once on the comet, but
05:44three times.
05:45The harpoons that were meant to dig Feely into the comet's surface securely had not fired, and the lander appeared
05:53to be rotating after the first touchdown.
05:56And then the lander lifted from the surface, for one hour and fifty minutes.
06:01During that time, it travelled about one kilometre at a speed of 38 centimetres per second.
06:09It then made a smaller, second hop, travelling at about three centimetres per second, and landing in its final resting
06:17place seven minutes later.
06:20This left Feely in an awkward angle, but it was still able to conduct its onboard experiments, and send data
06:27back down to us here on Earth.
06:30However, the landing spot had limited sunlight, meaning the solar panels could not be charged, and Feely eventually lost power
06:38after 57 hours.
06:41In the end, about 80% of the planned science was completed, not bad considering the circumstances.
06:49Meanwhile, Rosetta continued to study the environment of the comet, studying the dust particles which flew off as it became
06:56more active on its approach to the Sun, and monitored the changes on the surface.
07:03After 211 days, Rosetta noticed a strange signal. Scientists analysed the data and realised Feely had woken up, after seven
07:13months in hibernation.
07:15Engineers determined that Feely was exposed to sufficient sunlight to heat it to an acceptable operating temperature, and to generate
07:23electricity.
07:25This allowed for the experts to home in on the final resting place of Feely, and allow us to say
07:30a final goodbye.
07:39After becoming the first spacecraft to orbit a comet, and the first to deploy a lander, Feely, in November 2014,
07:46Rosetta continued to monitor the comet's evolution surviving the harsh environment of the comet for 786 days,
07:56making a few dramatic flybys close to its surface, surviving several unexpected outbursts from the comet,
08:03and recovered from two spacecraft safe modes.
08:08After almost two years in operation around the comet, and 12 years in space,
08:12Rosetta's own mission would also come to an end on the surface of the comet, with a controlled impact.
08:20Confirmation of the end of the mission arrived at our control centre at 1319 Central European Summer Time,
08:28with the loss of Rosetta's signal upon impact.
08:32The descent gave Rosetta the opportunity to study the comet right up until its last moment.
08:38The world may have said goodbye to Rosetta, but its legacy will not be forgotten.
08:44Rosetta changed our view of how the solar system formed, how the planets were made,
08:50and gave a glimpse at how life could have begun here on Earth.
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