Highlights From ESA's Rosetta Mission Landing On Comet 67P

Space.com

The Philae lander from European Space Agency's Rosetta mission's landed on Comet 67P/Churyumov-Gerasimenko.   Credit:  ESA - European Space Agency

Transcript

00:00This is the moment we made history by landing on a comet.

00:12Ten years ago, our Rosetta mission got up close and personal with a comet, landing a

00:17probe called Philae on the surface to directly study the properties of a comet for the first

00:24time ever.

00:27The mission was groundbreaking, it was only the seventh celestial object we have landed

00:31on before.

00:34It was an ambitious journey filled with many ups and downs, but we're getting ahead of

00:39ourselves.

00:40Let's take a look back at the mission ten years on.

00:53Comets are large objects made of dust and ice that have elliptical orbits around the

00:57sun, which stretch far out into the outer edges of the solar system.

01:04They are believed to be left over from when the planets formed, and scientists think they

01:08could hold the answers to how life formed on Earth, why we have water on Earth, and

01:14how the solar system evolved.

01:18You may recognise comets from their distinctive bright tail, caused by the sun heating up

01:23the frozen comet's core as they head towards the inner solar system, leaving behind this

01:29bright streak of dust and gas.

01:33Most comets are too small and far away to see from Earth, even with some of the biggest

01:38telescopes, and when they do come close, their bright tail obscures our view of the actual

01:43comet itself, making 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.

02:06From here, it set off on its 10-year-long journey to Comet 67P Churyumov-Gerasimenko.

02:14The Comet was chosen as it originated in the Kuiper belt, but does not venture out much

02:19farther than Jupiter anymore, making it perfect to align with Rosetta's journey.

02:25However, the journey was anything but simple.

02:29Rosetta required some energy boosts along the way, starting with a gravity assist of

02:34Earth, just a year after launch, which sent the spacecraft on towards Mars for another

02:39boost.

02:41From here, Rosetta came back to Earth before passing by the diamond-shaped asteroid Stainez

02:48and returning back to Earth for one final boost.

02:51Rosetta then got on its way to deeper space, flying past the huge ancient rock Laetitia,

02:58grabbing photos and data along the way.

03:02After all of this excitement, as Rosetta travelled on farther from the Sun, it did

03:07not have enough solar power to operate fully, so was put into standby mode, sending the

03:13spacecraft into a two-year, seven-month and 12-day slumber.

03:19In January 2014, the world sent Rosetta a wake-up call, and the team got sent to work

03:25to make sure all the instruments on board were working after the long break.

03:31The spacecraft still had 10 more manoeuvres to perform to align it correctly with the

03:36comet, and to get it to the right speed so it would be captured by the comet's gravity

03:42and not be flung off into space.

03:52As Rosetta approached Comet 67P, scientists spotted something unusual.

03:58The team expected to see that the central part of the comet, its nucleus, is sort of

04:03shaped like a potato, but instead, the images Rosetta sent back resembled more of a rubber

04:09duck shape.

04:10It had two lobes, almost as if the two comets had slammed into each other and bonded.

04:18It looked like nothing we had ever examined in the solar system before.

04:23This made landing Philae a bit more complicated.

04:26The complex shape of the comet made for a complex gravity and a strange rotation situation,

04:34which made flying around it very complicated.

04:37There were also craters, cliffs, sinkholes and boulders the size of houses, which had

04:42to be taken into account.

04:46Rosetta spent a few weeks analysing the comet, sending back information so the experts could

04:51determine where was best to land.

04:53Typically landing sites, for example on Mars, take years to select, so for Philae it happened

05:00exceptionally 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 Philae, and the probe was

05:15sent down, and the world held its breath for seven hours to hear if the spacecraft landed

05:21successfully.

05:24Touchdown was confirmed at 1703 CET on 12 November, but there was something strange

05:32about the data returned.

05:35Soon scientists, flight dynamics specialists and engineers concluded that Philae did not

05:40just touch down once on the comet, but three times.

05:46The harpoons that were meant to dig Philae into the comet's surface securely had not

05:51fired and the lander appeared to be rotating after the first touchdown.

05:56And then the lander lifted from the surface, for one hour and fifty minutes.

06:02During 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 3 centimetres per second, and landing

06:15in its final resting place seven minutes later.

06:21This left Philae in an awkward angle, but it was still able to conduct its on-board

06:25experiments and send data back down to us here on Earth.

06:30However, the landing spot had limited sunlight, meaning the solar panels could not be charged,

06:37and Philae eventually lost power after 57 hours.

06:41In the end, about 80% of the planned science was completed.

06:46Not bad considering the circumstances.

06:49Meanwhile Rosetta continued to study the environment of the comet, studying the dust particles

06:54which flew off as it became more active on its approach to the Sun, and monitored the

06:59changes on the surface.

07:03After 211 days, Rosetta noticed a strange signal.

07:08Scientists analysed the data and realised Philae had woken up, after seven months in

07:14hibernation.

07:15Engineers determined that Philae was exposed to sufficient sunlight to heat it to an acceptable

07:20operating temperature, and to generate electricity.

07:25This allowed for the experts to home in on the final resting place of Philae, and allow

07:30us to say a final goodbye.

07:39After becoming the first spacecraft to orbit a comet, and the first to deploy a lander,

07:45Philae, in November 2014, Rosetta continued to monitor the comet's evolution surviving

07:51the harsh environment of the comet for 786 days, making a few dramatic flybys close to

07:58its surface, surviving several unexpected outbursts from the comet, and recovered from

08:05two spacecraft safe modes.

08:09After almost two years in operation around the comet, and 12 years in space, Rosetta's

08:14own 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

08:27Summer Time, with the loss of Rosetta's signal upon impact.

08:33The descent gave Rosetta the opportunity to study the comet right up until its last moments.

08:39The 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.

08:57NASA Jet Propulsion Laboratory, California Institute of Technology

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