Rosetta Comet is Darker than Charcoal   
       
   Sept. 5, 2014:  A NASA instrument aboard the European Space Agency's (ESA's)   
   Rosetta orbiter has successfully made its first delivery of science data from   
   comet 67P/Churyumov-Gerasimenko.   
       
   The instrument, named Alice, began mapping the comet's surface last month,   
   recording the first far-ultraviolet light spectra of the comet's surface. From   
   the data, the Alice team discovered the comet is unusually dark -- darker than   
   charcoal-black -- when viewed in ultraviolet wavelengths.  Alice also detected   
   both hydrogen and oxygen in the comet's coma, or atmosphere.   
       
   http://www.nasa.gov/sites/default/files/pia17666_9.jpg   
       
   Artist's impression of the Rosetta orbiter at comet 67P/Churyumov-Gerasimenko.   
   The image is not to scale.   
   Image Credit:  ESA/ATG Medialab   
       
   Rosetta scientists also discovered the comet's surface so far shows no large   
   water-ice patches. The team expected to see ice patches on the comet's surface   
   because it is too far away for the sun's warmth to turn its water into vapor.   
       
   "We're a bit surprised at just how unreflective the comet's surface is and how   
   little evidence of exposed water-ice it shows," said Alan Stern, Alice   
   principal investigator at the Southwest Research Institute in Boulder,   
   Colorado.   
       
   Alice is probing the origin, composition and workings of comet 6   
   P/Churyumov-Gerasimenko, to gather sensitive, high-resolution insights that   
   cannot be obtained by either ground-based or Earth-orbiting observation. It   
   has more than 1,000 times the data-gathering capability of instruments flown a   
   generation ago, yet it weighs less than nine pounds (four kilograms) and draws   
   just four watts of power. The instrument is one of two full instruments on   
   board Rosetta that are funded by NASA. The agency also provided portions of   
   two other instrument suites.   
       
   Other U.S. contributions aboard the spacecraft are the Microwave Instrument   
   for Rosetta Orbiter (MIRO), the Ion and Electron Sensor (IES), part of the   
   Rosetta Plasma Consortium Suite, and the Double Focusing Mass Spectrometer   
   (DFMS) electronics package for the Rosetta Orbiter Spectrometer for Ion   
   Neutral Analysis (ROSINA). They are part of a suite of 11 total science   
   instruments aboard Rosetta.   
       
   MIRO is designed to provide data on how gas and dust leave the surface of the   
   nucleus to form the coma and tail that gives comets their intrinsic beauty.   
   IES is part of a suite of five instruments to analyze the plasma environment   
   of the comet, particularly the coma.   
       
   To obtain the orbital velocity necessary to reach its comet target, the   
   Rosetta spacecraft took advantage of four gravity assists (three from Earth,   
   one from Mars) and an almost three-year period of deep space hibernation,   
   waking up in January 2014 in time to prepare for its rendezvous with   
   67P/Churyumov-Gerasimenko.   
       
   Rosetta also carries a lander, Philae, which will drop to the comet's surface   
   in November 2014.   
       
   The comet observations will help scientists learn more about the origin and   
   evolution of our solar system and the role comets may have played in providing   
   Earth with water, and perhaps even life.   
       
   Credits:   
   Production editor: Dr. Tony Phillips | Credit: Science@NASA   
       
   More information:   
       
   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 in Cologne; Max Planck Institute for Solar System Research in   
   G”ttingen; French National Space Agency in Paris; and the Italian Space Agency   
   in Rome.   
       
   NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California, manages the   
   U.S. contribution to the Rosetta mission for the agency's Science Mission   
   Directorate in Washington. JPL also built the MIRO instrument and hosts its   
   principal investigator, Samuel Gulkis. The Southwest Research Institute,   
   located in San Antonio and Boulder, developed Rosetta's IES and Alice   
   instruments and hosts their principal investigators, James Burch (IES) and   
   Alan Stern (Alice).   
       
   For more information on the U.S. instruments aboard Rosetta, visit:   
   http://rosetta.jpl.nasa.gov   
       
   More information about Rosetta is available at: http://www.esa.int/rosetta   
       
       
   Regards,   
       
   Roger   
      
   --- D'Bridge 3.99   
    * Origin: NCS BBS - Houma, LoUiSiAna (1:3828/7)