Copyright: (ESA/Rosetta/NavCam)
On 12 November, Rosetta’s Philae probe is set to make the first-ever landing on a comet when it touches down on Comet 67P/Churyumov–Gerasimenko.
Comet Churyumov–Gerasimenko is the destination of the Rosetta spacecraft mission, launched 2004, which rendezvoused with it in 2014 and, if successful, will be the first mission to land a space probe on a comet.
Advance work
As preparation for the Rosetta mission, Hubble Space Telescope pictures taken on 12 March 2003 were closely analysed. An overall 3D model was constructed and computer-generated images were created. On 25 April 2012, the most detailed observations to date were taken with the 2-metre Faulkes Telescope by N. Howes, G. Sostero and E. Guido while it was at its aphelion.
On 6 June 2014 water vapor was detected being released at a rate of roughly 1 L/s (0.26 USgal/s) when Rosetta was 360,000 km (220,000 mi) from Churyumov–Gerasimenko and 3.9 AU (580,000,000 km) from the Sun. On 14 July 2014, images taken by Rosetta showed that its nucleus is irregular in shape with two distinct sections. One explanation is that it is a contact binary formed by a collision between two comets, but other formation scenarios exist: for example, it may have been gravitationally affected by another object, or significant amounts of ice may have sublimated from its surface to leave behind an asymmetric shape. The size of the nucleus is estimated to be 3.5×4 km (2.2×2.5 mi).
Rendezvous and orbit
Beginning in May 2014, Rosetta 's velocity was reduced by 780 m/s (2,800 km/h; 1,700 mph) with a series of thruster firings. Ground controllers rendezvoused Rosetta with Churyumov–Gerasimenko on 6 August 2014. This was done by reducing Rosetta 's relative velocity to 1 m/s (4 km/h; 2 mph). Rosetta entered orbit on 10 September, at about 30 km (19 mi) from the nucleus.
Landing
Descent of a small lander is planned for 12 November 2014. Philae is a 100 kg (220 lb) robotic probe that will set down on the surface with landing gear and “harpoon itself to the surface”. The landing site has been christened Agilkia in honour of Agilkia Island, where the temples of Philae Island were relocated after the construction of the Aswan Dam flooded the island. The acceleration due to gravity on the surface of Churyumov–Gerasimenko has been estimated for simulation purposes at 10−3 m/s2, or about one ten-thousandth of that on Earth.
Interesting article with the details of the mission on the BBC website - Rosetta mission: ‘Looking good’ for comet landing bid
What do you think about this mission?
