Candidate Comet Landing Sites Identified   
       
   August 26, 2014:  The European Space Agency's Rosetta mission has chosen five   
   candidate landing sites on comet 67P/Churyumov-Gerasimenko for its Philae   
   lander. Philae's descent to the comet's nucleus, scheduled for this November,   
   will be the first such landing ever attempted.   
       
   http://tinyurl.com/q2qoopb   
       
   This annotated image depicts four of the five potential landing sites for   
   Rosetta's Philae lander.  Image credit: ESA/Rosetta/MPS for OSIRIS Team   
   MPS/UPD/LAM/IAA/SSO/INTA/UPM  Full image and caption.   
       
   "This is the first time landing sites on a comet have been considered," said   
   Stephan Ulamec, Philae Lander Manager at the German Aerospace Center, Cologne,   
   Germany. "The candidate sites that we want to follow up for further analysis   
   are thought to be technically feasible on the basis of a preliminary analysis   
   of flight dynamics and other key issues - for example, they all provide at   
   least six hours of daylight per comet rotation and offer some flat terrain. Of   
   course, every site has the potential for unique scientific discoveries."   
       
   For each possible zone, important questions must be asked: Will the lander be   
   able to maintain regular communications with Rosetta? How common are surface   
   hazards such as large boulders, deep crevasses or steep slopes? Is there   
   sufficient illumination for scientific operations and enough sunlight to   
   recharge the lander's batteries beyond its initial 64-hour lifetime without   
   causing overheating?   
       
   The potential landing sites were assigned a letter from an original   
   pre-selection of 10 possible sites, which does not signify any ranking. Three   
   sites (B, I and J) are located on the smaller of the two lobes of the comet   
   and two sites (A and C) are located on the larger lobe.   
       
   [See above link]   
       
   This annotated image depicts two of the five potential landing sites for   
   Rosetta's Philae lander, including one ("C") not shown in the image above.   
   Image credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM     
   "The process of selecting a landing site is extremely complex and dynamic; as   
   we get closer to the comet, we will see more and more details, which will   
   influence the final decision on where and when we can land," said Fred Jansen,   
   Rosetta's mission manager from the European Space Agency's Science and   
   Technology Centre in Noordwijk, The Netherlands. "We had to complete our   
   preliminary analysis on candidate sites very quickly after arriving at the   
   comet, and now we have just a few more weeks to determine the primary site.   
   The clock is ticking and we now have to meet the challenge to pick the best   
   possible landing site."   
       
   The next step in preparation for landing operations is a comprehensive   
   analysis of each of the candidate sites, to determine possible orbital and   
   operational strategies that could be used for Rosetta to deliver the lander to   
   any of them. At the same time, Rosetta will move to within 31 miles (50   
   kilometers) of the comet, allowing a more detailed study of the proposed   
   landing sites. By September 14, the five candidate sites will have been   
   assessed and ranked, leading to the selection of a primary landing site. A   
   fully detailed strategy for the landing operations at the selected site will   
   be developed, along with a backup.   
       
   The landing of Philae is expected to take place in mid-November when the comet   
   is about 280 million miles (450 million kilometers) from the sun. This will be   
   before activity on the comet reaches levels that might jeopardize the safe and   
   accurate deployment of Philae to the comet's surface, and before surface   
   material is modified by this cometary activity.   
       
   Rosetta is an international mission spearheaded by the European Space Agency   
   with support and instruments provided by NASA.   
       
   For more information on the U.S. instruments aboard Rosetta, visit:   
   http://rosetta.jpl.nasa.gov.  The ESA's Rosetta home page is at    
   ttp://www.esa.int/rosetta .   
       
   Credits:   
   Production editor: Dr. Tony Phillips | Credit: Science@NASA   
       
   More information:   
       
   Choosing the right landing site is a complex process. It must balance the   
   technical needs of the orbiter and lander during all phases of the separation,   
   descent and landing, and during operations on the surface, with the scientific   
   requirements of the 10 instruments on board Philae. A key issue is that   
   uncertainties in navigating the orbiter close to the comet mean that it is   
   possible to specify any given landing zone only in terms of an ellipse -   
   covering up to six-tenths of a square mile (one square kilometer) - within   
   which Philae might land.   
       
   Launched in March 2004, Rosetta was reactivated in January 2014 after a record   
   957 days in hibernation. Composed of an orbiter and lander, Rosetta's   
   objectives since arriving at comet 67P/Churyumov-Gerasimenko earlier this   
   month are to study the celestial object up close in unprecedented detail,   
   prepare for landing a probe on the comet's nucleus in November, and track its   
   changes through 2015, as it sweeps past the sun.   
       
   Comets are time capsules containing primitive material left over from the   
   epoch when the sun and its planets formed. Rosetta's lander will obtain the   
   first images taken from a comet's surface and will provide comprehensive   
   analysis of the comet's possible primordial composition by drilling into the   
   surface. Rosetta also will be the first spacecraft to witness at close   
   proximity how a comet changes as it is subjected to the increasing intensity   
   of the sun's radiation. Observations will help scientists learn more about the   
   origin and evolution of our solar system and the role comets may have played   
   in seeding Earth with water, and perhaps even life.   
       
   The scientific imaging system, OSIRIS, was built by a consortium led by the   
   Max Planck Institute for Solar System Research (Germany) in collaboration with   
   Center of Studies and Activities for Space, University of Padua (Italy), the   
   Astrophysical Laboratory of Marseille (France), the Institute of Astrophysics   
   of Andalusia, CSIC (Spain), the Scientific Support Office of the European   
   Space Agency (Netherlands), the National Institute for Aerospace Technology   
   (Spain), the Technical University of Madrid (Spain), the Department of Physics   
   and Astronomy of Uppsala University (Sweden) and the Institute of Computer and   
   Network Engineering of the TU Braunschweig (Germany). OSIRIS was financially   
   supported by the national funding agencies of Germany (DLR), France (CNES),   
   Italy (ASI), Spain, and Sweden and the ESA Technical Directorate.   
       
   Rosetta is an ESA mission with contributions from its member states and NASA.   
   Rosetta's Philae lander is provided by a consortium led by the German   
   Aerospace Center, Cologne; Max Planck Institute for Solar System Research,   
   Gottingen; French National Space Agency, Paris; and the Italian Space Agency,   
   Rome. NASA's Jet Propulsion Laboratory in Pasadena, California, a division of   
   the California Institute of Technology, manages the U.S. participation in the   
   Rosetta mission for NASA's Science Mission Directorate in Washington.   
       
       
   Regards,   
       
   Roger   
      
   --- D'Bridge 3.99   
    * Origin: NCS BBS - Houma, LoUiSiAna (1:3828/7)