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In Germany’s Darmstadt, the European Space Agency (ESA) was a scene of jubilation early today (Indian time) as scientists celebrated the landing of a robotic probe, Philae, on a comet in what was considered to be an impossible feat. This news made headlines the world over. So what exactly is Philae? And why is there such excitement over a robot landing on a piece of rock (it’s not Mars or Jupiter after all)?
Here are a few facts compiled from reports by The Guardian, the BBC and The New York Times.
1. The ESA launched the Rosetta satellite in March 2004 to chase Comet 67P/Churyumov-Gerasimenko, which took place on 6 August 2014. Rosetta’s journey took 10 years and it has travelled a distance of 6.4 billion km. Since that time, Rosetta has been orbiting the comet, gearing to launch its robotic probe, Philae on to 67P’s surface. On November 12, scientists at ESA confirmed that Philae successfully detached from Rosetta and made a precarious “second landing” on the comet, while the mother ship “has now moved out of radio ‘visibility,’” BBC reports.
2. Celebrations at ESA were marred by uncertainty as two harpoons built into Philae, which were supposed to anchor the craft to the surface of the comet, failed to launch. This “raised fears about the lander’s stability and chances of clinging on to the comet for long,” The Guardian mentions. The New York Times states that “fluctuations in the radio link and the generation of power by the solar panels suggested that Philae may have bounced off the surface before settling down again,” thus accounting for the “second landing.”
3. The aim of the Rosetta mission is to study comets which are made of materials that pre-date the birth of our solar system. With Philae on the surface of 67P, scientists hope to get a better understanding “of how the solar system formed and how comets carried water and complex organics to the planets, preparing the stage for life on Earth,” reports The Guardian.
4. Among the different theories on the origins of life on Earth, one holds that comets were the source of water for our planet and “could have ‘seeded’ the Earth with the chemistry needed to help kick-start life,” BBC reports.
5. The landing faced not quite a few difficulties: The comet was between the orbits of Mars and Jupiter when Philae landed and was moving at a pace of 18km/s in space. “At so vast a distance, even radio signals travelling at the speed of light take nearly half an hour to travel from Earth to the spacecraft, making real-time control of the landing impossible,” states The Guardian. Besides this, the shape of Philae made scientists fear a landing failure as the surface of 67P is covered with “hills and spectacular jutting cliffs gave way to cratered plains strewn with boulders.” Rosetta circled the comet for many weeks to create a map to mark an appropriate landing spot which “had to be fairly flat and clear of boulders, but with a good view of the whole comet and plenty of sunlight to charge the lander’s batteries,” says The Guardian. Scientists named the landing spot that was chosen as Agilkia, located at the comet’s “head”.
6. Besides trying to decipher questions related to the origins of the solar system, Philae will gather information about 67P’s density, temperature and chemical makeup, and “it will also capture dust and gas released in ever more violent jets from the comet’s nucleus as it nears the sun,” reports The Guardian. On board Philae are 10 instruments which will be used to analyse these functions. The Guardian reports that one instrument referred to as Ptolemy will “bake pieces of comet material” to gain an understanding of the comet’s composition, while another one ‘Consert’ will relay radio waves through the comets body to determine the body’s structure.
7. The Rosetta mission is expected to run till December 2015 and can be extended by another six months if enough fuel is available. Philae is powered by a battery that lasts 40 hours which can be recharged by sunlight, states The Guardian.
8. The mission derives its name from the Rosetta Stone which was used to decipher Egyptian hieroglyphics, while Philae was an island (now submerged in Lake Nasser, Egypt) “where an obelisk provided clues to solving the Rosetta Stone,” reports The New York Times.
The Verge has put together some spectacular photos of the Rosetta’s journey from Earth to 67P.
