Solar Probe+ to Plunge Directly into Sun's Atmosphere   
       
   Sept. 2, 2010:  NASA's daring plan to visit the sun took a giant leap forward   
   today with the selection of five key science investigations for the Solar   
   Probe+ spacecraft.    
       
   Slated to launch no later than 2018, the smart car-sized spacecraft will   
   plunge directly into the atmosphere of the sun, aiming to solve some of the   
   biggest mysteries of solar physics. Today's announcement means that   
   researchers can begin building sensors for unprecedented in situ measurements   
   of the solar system's innermost frontier.   
       
   "Solar Probe+ is going where no spacecraft has gone before," says Lika   
   Guhathakurta, Solar Probe+ program scientist at NASA HQ. "For the first time,   
   we'll be able to 'touch, taste and smell' the sun."   
   [...]   
   Click on the image to view a pdf fact sheet about Solar Probe+. See also     
   "NASA Plans to Visit the Sun" from Science@NASA.   
       
   Last year, NASA invited top researchers around the world to submit proposals   
   detailing possible science investigations for the pioneering spacecraft.   
   Thirteen proposals were received and five have been selected:   
       
   --SWEAP, the Solar Wind Electrons Alphas and Protons Investigation: The most   
   abundant particles in the solar wind are electrons, protons and helium ions.   
   SWEAP will count these particles and measure their properties, even "sweeping   
   up" some of them in a special Solar Probe Cup for direct analysis. The   
   principal investigator is Justin C. Kasper of the Smithsonian Astrophysical   
   Observatory in Cambridge, Mass.   
   [...]   
   An artist's concept of Solar Probe+, heat shield up and solar panels folded.     
   [more] --WISPR, the Wide-field Imager for Solar Probe Plus: WISPR is a   
   telescope that will make 3D images of the sun's atmosphere similar to medical   
   CAT scans. WISPR can actually see the solar wind, allowing it to image clouds   
   and shock waves as they approach and pass the spacecraft. This telescope is an   
   important complement to the spacecraft's in situ instruments, which sample the   
   plasmas that WISPR images. The principal investigator is Russell Howard of the   
   Naval Research Laboratory in Washington, DC.   
       
   --FIELDS, The Fields Investigation for Solar Probe Plus: This instrument will   
   make direct measurements of electric and magnetic fields, radio emissions, and   
   shock waves which course through the sun's atmospheric plasma. FIELDS also   
   turns Solar Probe Plus into a giant dust detector, registering voltage   
   signatures when specks of space dust hit the spacecraft's antenna. The   
   principal investigator is Stuart Bale of the University of California in   
   Berkeley.   
       
   --ISIS, Integrated Science Investigation of the Sun: The ISIS EPI-Hi and   
   EPI-Lo instruments will monitor electrons, protons and ions which are   
   accelerated to high energies by shock waves in the sun's atmosphere. These are   
   the very same particles that pose a threat to astronauts in space, disable   
   satellites, and ionize Earth's upper atmosphere.   
       
   --Solar Probe+ Observatory Scientist: This was a proposal not for an   
   instrument, but for a person. The principal investigator, Marco Velli, becomes   
   the mission's Observatory Scientist. In the years ahead, he will become deeply   
   familiar with the spacecraft and its construction, helping to ensure that   
   adjacent in situ instruments do not interfere with one another as they sample   
   the solar environment. He will also guide the mission's "big picture" science   
   investigations after Solar Probe+ enters the sun's atmosphere.   
       
   "The sensors we've selected to ride aboard Solar Probe+ are designed to solve   
   some of the biggest mysteries of solar physics," says Dick Fisher, head of   
   NASA's Heliophysics Division in Washington DC.   
   [...]   
   Solar Probe+ passes Venus en route to the sun. [animations] Why is the sun's   
   atmosphere is so much hotter than its surface? And what propels the solar wind?   
       
   "We've been struggling with these questions for decades," says Fisher. "Solar   
   Probe+ should finally provide some answers."   
       
   Solar Probe+ will likely discover new mysteries, too, in a realm that no other   
   spacecraft has dared enter. At closest approach, Solar Probe+ will be 7   
   million km or 9 solar radii from the sun. There, the spacecraft's   
   carbon-composite heat shield must withstand temperatures as high as 2000   
   degrees C and survive blasts of radiation that would quickly disable other   
   missions. From these near distances inside the sun's atmosphere, the solar   
   disk will loom 23 times wider than it does in the skies of Earth.   
       
   "What will we find there?" wonders Guhathakurta. "This is truly unexplored   
   territory." By design, Solar Probe's winning instruments are sufficiently   
   versatile to investigate many different kinds of phenomena. Whatever comes   
   along--be it electric or magnetic, high- or low-energy, wavy or    
   urbulent--they should be able to measure it.   
       
   "The possibilities for discovery," she says, "are off the charts."   
       
       
   Author: Dr. Tony Phillips | Credit: Science@NASA   
       
   More Information   
   The Solar Probe Plus mission is part of NASA's Living with a Star Program. The   
   program is designed to understand the aspects of the sun and the Earth's space   
   environment that affect life and society. The program is managed by NASA's   
   Goddard Space Flight Center in Greenbelt, Md., with oversight from NASA's   
   Science Mission Directorate's Heliophysics Division at NASA Headquarters in   
   Washington. The Johns Hopkins University Applied Physics Laboratory in Laurel,   
   Md., is the prime contractor for the spacecraft.   
       
   NASA Plans to Visit the Sun -- Science@NASA   
       
   Solar Probe Plus, a NASA Mission to Touch the Sun -- APL home page   
       
   Solar Probe+ -- NASA home page   
       
       
   Regards,   
       
   Roger   
      
   --- D'Bridge 3.54   
    * Origin: NCS BBS (1:3828/7)