ESA picks landing site for Rosetta's Philae lander - 'J' marks the spot!
Monday, September 15, 2014, 3:26 PM - With less than two months to go before the ESA's Rosetta spacecraft releases its Philae lander to set down on the surface of Comet 67P/Churyumov-Gerasimenko, mission scientists have narrowed down the potential landing sites from ten to just one.
Selecting potential landing sites on the surface was difficult, due to the shape of the comet. Considered to be a 'contact binary' - meaning that there are technically two distinct parts of the comet, which are joined together at a narrow point between them - Comet 67/P has has proved to be more of a challenge than your typical 'dirty snowball in space'. Part of the problem is picking somewhere the lander can safely touch down without damage, but where it can still communicate with Rosetta and have enough access to sunlight to recharge its batteries. Another consideration is that they wanted to pick somewhere actually scientifically interesting, as it would be a shame to set down somewhere only to discover another location on the comet would have generated better scientific results. In total, the science team selected 10 potential sites, labelled A through J (not ranked in any specific order).
In the end, as was announced at a media event on Monday, Sept. 15, Site J turned out to be the best option.
"As we have seen from recent close-up images, the comet is a beautiful but dramatic world - it is scientifically exciting, but its shape makes it operationally challenging," Stephan Ulamec, the Philae Lander Manager at the DLR German Aerospace Center, said in an ESA press release. "None of the candidate landing sites met all of the operational criteria at the 100% level, but Site J is clearly the best solution."
Site J is located at the top of the 'head' of the duck-shaped comet, and Jean-Pierre Bibring, who is the principal investigator of Philae's CIVA instrument, which will provide panoramic and microscopic imaging of the comet, told the ESA: "Site J in particular offers us the chance to analyse pristine material, characterize the properties of the nucleus, and study the processes that drive its activity."
The backup site, will be used in the case where conditions change enough at Site J before November 11th that it forces the team to reconsider, is Site C, which is located on the 'body' of the comet.
Rosetta is still holding position at 30 kilometres from Comet 67/P, while it continues the mapping phase of the mission. Over the month of October, the spacecraft will close with the comet, until it is roughly 10 kilometres away, and it will release the lander, Philae, from that distance to land on the surface on November 11, 2014.
The announcement from the Rosetta mission team, which was made at the ESA headquarters in Paris, France, along with discussions about the decision, what the scientists hope to find on the surface, and what's to come in the time leading up to the landing, is in the 90-min video presentation below: