The Rosetta Mission - 1st Landing on a Comet

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The Rosetta Mission - 1st Landing on a Comet

Set: Part No: ST011546
S/S: Part No: ST011547
FDC: Part No: ST011548
S/S FDC: Part No ST011549
CTO Part No: ST011550
S/S CTO: Part No: ST011551
Ascension Island sends its congratulations to the ESA and all involved in the Rosetta Mission.

Comets have inspired awe and wonder since the dawn of history. Many scientists today believe that comets crashed into Earth in its formative period spewing organic molecules that were crucial to the growth of life. Comets may have formed about the same time as the giant planets of our solar system (Jupiter, Saturn, Uranus, and Neptune) - about 4.6 billion years ago. Some scientists think that comets and planets were both made from the same clumps of dust and ice that spewed from our Sun’s birth; others think that these roving time capsules are even older than that, and that they may contain grains of interstellar stuff that is even older than our solar system!

Rosetta is a robotic space probe launched by the European Space Agency (ESA). Along with its lander module, Philae, Rosetta’s ten-year mission was to catch the comet 67P/Churyumov-Gerasimenko (67P) and to answer some of our questions about comets.

The Rosetta spacecraft is named after the ancient Rosetta Stone that you can visit in London’s British Museum. The Philae lander is named after the Philae Obelisk which, together with the Rosetta Stone, provided the key to our first understanding of Egyptian hieroglyphs. Scientists hope that the Rosetta spacecraft will enable us to translate the even older language of comets, as expressed by their thermal signatures, into new knowledge about the origins of our solar system and, perhaps, life on Earth. This daring international mission is spearheaded by the ESA with key support and instruments from NASA.

Rosetta was launched aboard an Ariane 5 space rocket on 2 March 2004 from the Guiana Space Centre in French Guiana. Rosetta's Ariane 5 soon passed out of range of the Galliot tracking station, near Kourou, and was followed in its journey around the world by tracking stations in Brazil, Ascension Island (shown on the souvenir sheet), Kenya, Australia and Hawaii. In order to know what to expect on the day, all these places had rehearsed the launch during the preceding months.

The launch of Rosetta was a particular challenge as it was the first time Ariane 5 had placed a spacecraft onto an Earth-escape trajectory. To do this, an unprecedented delayed ignition of the Ariane 5 upper stage was needed. 106 minutes after Rosetta had been placed into space the upper stage ignited and powered Rosetta away from the Earth towards its icy rendezvous. Despite the hundreds of millions of kilometres that Rosetta would eventually travel 99.8% of the propellant needed for the mission was consumed during the first hundred kilometres as the rocket struggled to slice a path through the atmosphere and escape Earth's gravity.

To achieve the required velocity to rendezvous with 67P, Rosetta used gravity assist manoeuvres to accelerate throughout the inner Solar System. The first flyby of Earth occurred on 4 March 2005. On 25 February 2007, the craft was scheduled for a low-altitude bypass of Mars (during which Rosetta returned detailed images of the surface and atmosphere of the planet). The second Earth flyby occurred on 13 November 2007. Rosetta 's third and final flyby of Earth happened on 12 November 2009.

In August 2014, Rosetta rendezvoused with the comet 67P, after a journey of some 6.4 billion kilometres through the solar system, and entered actual orbit about it in September. The surface layout of 67P was unknown before Rosetta 's arrival. The orbiter mapped the comet in anticipation of detaching its lander and five potential landing sites were identified before the ESA announced Site J, named Agilkia, as the lander's destination.

On 12 November 2014, 510 million kilometres from earth, Philae detached from Rosetta and approached 67P at a relative speed of around 1 m/s (2.2 mph). It bounced twice, but Philae’s soft landing on the comet was the first time in history that such an extraordinary feat has been achieved. Confirmation of contact with 67P reached Earth at 16:03 GMT. After landing on the comet Philae commenced its science missions.

“After more than 10 years travelling through space, we’re now making the best ever scientific analysis of one of the oldest remnants of our Solar System,” said Alvaro Giménez, ESA’s Director of Science and Robotic Exploration. “Decades of preparation have paved the way for today’s success, ensuring that Rosetta continues to be a game-changer in cometary science and space exploration.”

Although the future of the lander Philae is uncertain, Rosetta is the workhorse of the mission and its work will continue as it escorts the comet around the sun.

Technical Details
Designer                                    Bee Design
Printer                                        BDT International
Process                                     Stochastic lithography
Stamp Size                                28.45 x 42.58mm
Sheet Format                             10
Souvenir Sheet Size                    100 x 70mm
Perforation                                  14 per 2cms
Release Date                              30 December 2014
Production Co-ordination              Creative Direction (Worldwide) Ltd

ESA logo used with permission from the European Space Agency.
Photographic Credits:
35p  © ESA/CNES/ARIANEPACE- Service Optique
55p  ©ESA–J. Huart 
65p  ©ESA/ATG medialab; comet image ©ESA/Rosetta/NAVCAM
£1.60  ©ESA/ATG medialab
S/S comet ©ESA/Rosetta/NAVCAM; border ©ESA/ATG medialab
S/S ESA Tracking Station, Ascension © Colin R Duncan
FDC ©ESA–J. Huart; comet image ©ESA/Rosetta/NAVCAM