Rosetta Arrives at Target Comet   
       
   August 6, 2014:  Today, after a decade-long journey chasing its target, the   
   European Space Agency's Rosetta probe, carrying three NASA instruments, became   
   the first spacecraft to rendezvous with a comet, 67P/Churyumov-Gerasimenko.   
       
   "After 10 years, five months and four days travelling towards our destination,   
   looping around the sun five times and clocking up 6.4 billion kilometers, we   
   are delighted to announce finally we are here," said Jean-Jacques Dordain,   
   ESA's director General.   
       
   http://www.nasa.gov/content/rosettas-target-up-close/   
       
   Comet 67P/Churyumov-Gerasimenko by Rosetta's OSIRIS narrow-angle camera on   
   August 3, 2014, from a distance of 177 miles (285 kilometers). Credits:   
   ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA Full   
   image and caption   
       
   The latest images of the comet taken by Rosetta are available at   
   http://www.nasa.gov/rosetta   
       
   Comet 67P/Churyumov-Gerasimenko and Rosetta are 252 million miles (405 million   
   kilometers) from Earth, about halfway between the orbits of Jupiter and Mars.   
   The comet is in an elliptical, 6.5-year orbit that takes it from beyond   
   Jupiter at its farthest point, to between the orbits of Mars and Earth at its   
   closest to the sun. Rosetta will accompany the comet for over a year as it   
   swings around the sun and back out towards Jupiter again.   
       
   Rosetta is 62 miles (100 kilometers) from the comet's surface. Over the next   
   six weeks, it will fly two triangular-shaped trajectories in front of the   
   comet, first at the 62-mile (100-kilometer) altitude and then down at 31 miles   
   (50 kilometers). At the same time, the spacecraft's suite of instruments will   
   provide a detailed scientific study of the comet, scanning the surface to   
   identify a target site for its comet lander, Philae. Eventually, Rosetta will   
   attempt a close, near-circular orbit at 19 miles (30 kilometers) and,   
   depending on the activity of the comet, may come even closer.   
       
   "Over the next few months, in addition to characterizing the comet nucleus and   
   setting the bar for the rest of the mission, we will begin final preparations   
   for another space history first: landing on a comet," said Matt Taylor,   
   Rosetta's project scientist from the European Space Agency's Science and   
   Technology Centre in Noordwijk, The Netherlands.   
       
   As many as five possible landing sites will be identified by late August,   
   before the primary site is identified in mid-September. The final timeline for   
   the sequence of events for deploying Philae -- currently expected for Nov. 11   
   -- will be confirmed by the middle of October.   
       
   http://www.nasa.gov/content/rosettas-target-up-close/   
       
   Close up detail focusing on a smooth region on the `base' of the `body'   
   section of comet 67P/Churyumov-Gerasimenko. The image was taken by Rosetta's   
   Onboard Scientific Imaging System (OSIRIS) on August 6, 2014. Credits:   
   ESA/Rosetta/MPS for OSIRIS Team  Full image and caption   
       
   Comets are considered to be primitive building blocks of the solar system and   
   may have helped to "seed" Earth with water, perhaps even the ingredients for   
   life. But many fundamental questions about these enigmatic objects remain, and   
   through a comprehensive, in situ study of the comet, Rosetta aims to unlock   
   the secrets within.   
       
   The three U.S. instruments aboard the spacecraft are the Microwave Instrument   
   for Rosetta Orbiter (MIRO), an ultraviolet spectrometer called Alice, and the   
   Ion and Electron Sensor (IES). They are part of a suite of 11 science   
   instruments aboard the Rosetta orbiter.   
       
   MIRO is designed to provide data on how gas and dust leave the surface of the   
   nucleus to form the coma and tail that give comets their intrinsic beauty.   
   Studying the surface temperature and evolution of the coma and tail provides   
   information on how the comet evolves as it approaches and leaves the vicinity   
   of the sun.   
       
   Alice will analyze gases in the comet's coma, which is the bright envelope of   
   gas around the nucleus of the comet developed as it approaches the sun. Alice   
   also will measure the rate at which the comet produces water, carbon monoxide   
   and carbon dioxide. These measurements will provide valuable information about   
   the surface composition of the nucleus.   
       
   The instrument also will measure the amount of argon present, an important   
   clue about the temperature of the solar system at the time the comet's nucleus   
   originally formed more than 4.6 billion years ago.   
       
   IES is part of a suite of five instruments to analyze the plasma environment   
   of the comet, particularly the coma. The instrument will measure the charged   
   particles in the sun's outer atmosphere, or solar wind, as they interact with   
   the gas flowing out from the comet while Rosetta is drawing nearer to the   
   comet's nucleus.   
       
   NASA also provided part of the electronics package for the Double Focusing   
   Mass Spectrometer, which is part of the Swiss-built Rosetta Orbiter   
   Spectrometer for Ion and Neutral Analysis (ROSINA) instrument. ROSINA will be   
   the first instrument in space with sufficient resolution to be able to   
   distinguish between molecular nitrogen and carbon monoxide, two molecules with   
   approximately the same mass. Clear identification of nitrogen will help   
   scientists understand conditions at the time the solar system was formed.   
       
   U.S. scientists are partnering on several non-U.S. instruments and are   
   involved in seven of the mission's 21 instrument collaborations. NASA's Deep   
   Space Network is supporting ESA's Ground Station Network for spacecraft   
   tracking and navigation.   
       
   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 upon arrival at comet 67P/Churyumov-Gerasimenko in August 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 as   
   it sweeps past the sun.   
       
   Credits:   
   Production editor: Dr. Tony Phillips | Credit: Science@NASA   
       
   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. JPL, a division of the California Institute of Technology, Pasadena,   
   manages the U.S. participation in the Rosetta mission for NASA's Science   
   Mission Directorate in Washington.   
       
   Web links:   
   European Space Agency home page   
       
   Rosetta -- from the ESA   
       
   Rosetta -- from NASA   
       
   NASA Instruments on Rosetta   
       
   Rosetta Comet Comes Alive -- from Science@NASA   
       
       
   Regards,   
       
   Roger   
      
   --- D'Bridge 3.99   
    * Origin: NCS BBS - Houma, LoUiSiAna (1:3828/7)