Dwarf Planet Mysteries Beckon to New Horizons   
       
   Sept. 2, 2011: At this very moment one of the fastest spacecraft ever launched   
   -- NASA's New Horizons -- is hurtling through the void at nearly one million   
   miles per day.  Launched in 2006, it has been in flight longer than some   
   missions last, and still has four more years of travel to go.   
       
   New Horizons headed for the lonely world of Pluto on the outer edge of the   
   solar system.   
       
   Although astronomers now call Pluto a dwarf planet, "it's actually a large   
   place, about 5,000 miles around at the equator," says Alan Stern, principal   
   investigator for the mission. "And it's never been explored."   
       
   http://www.youtube.com/watch?v=JtcIbJKZZQQ   
       
   Click to view a ScienceCast video about New Horizons' journey to Pluto.   
   [Youtube]   
       
   Indeed, no spacecraft has ever visited Pluto or any dwarf planet1.   
       
   "This is a whole new class of worlds," says Stern. "To understand the solar   
   system, we need to understand worlds like Pluto."   
       
   Pluto is a resident of the Kuiper Belt, a vast region beyond the orbit of   
   Neptune.  Stern believes "the Kuiper Belt contains a thousand dwarf planets or   
   more - a whole zoo of them! Dwarf planets are, in fact, the most numerous   
   class of planets in the solar system, and probably in the whole universe."   
       
   http://science.nasa.gov/science-news/science-at-nasa/2010/14apr_molasses/   
       
   The Hubble Space Telescope discovered strange molasses-colored markings on   
   Pluto. [full story] Pluto is a world of mysteries. For one thing, Stern   
   wonders, what are the molasses-colored patches on Pluto's surface seen by the   
   Hubble Space Telescope? Some scientists think they could be deposits of   
   primordial organic matter.  "New Horizon's spectrometers will help us identify   
   the kinds of organic molecules on Pluto. We expect to find something pretty   
   interesting."   
       
   Hubble recently contributed more intrigue by spotting a new moon circling   
   Pluto -- bringing the total to four.  Composite Hubble images of Pluto now   
   resemble a miniature planetary system.  New Horizons will hunt for even more   
   moons as it approaches the dwarf planet.   
       
   The probe is primed for detective work -- equipped with instruments capable of   
   "knocking the socks off anything Voyager carried." In addition to state of the   
   art spectrometers, New Horizons wields one of the largest and highest   
   resolution interplanetary telescopes ever flown. It's called LORRI, short for   
   Long-Range Reconnaissance Imager.   
       
   "At closest approach to Pluto - about 10,000 km up - LORRI can resolve details   
   almost as well as a spy camera. The view will be incredible. If we flew this   
   instrument over Earth at that altitude, we could see individual buildings and   
   their shapes."   
       
   What will we see on Pluto? Some researchers say we could spot icy geysers2.   
   Some say we could see those surface deposits of organic material. Stern says   
   simply, "There could be all kinds of surprises! It's a first exploration of a   
   new kind of planet."   
       
   Heading far from home, "New Horizons is like Noah's Ark - our ship has two of   
   everything, for backup," says Stern. "Two heaters, two computer systems, two   
   of everything except the scientific instruments. And even those have   
   capabilities to back each other up."   
       
   When New Horizons reaches Pluto it will have traveled 9 « years - longer than   
   any spacecraft has ever flown to reach its main target. To save power and   
   reduce wear and tear, it hibernates3 much of the time. But all systems will be   
   ready to spring into action upon arrival in 2015.   
       
   Mark your calendar.   
       
       
   Author: Dauna Coulter | Editor: Dr. Tony Phillips | Credit: Science@NASA   
       
   More Information   
   New Horizons -- JHU-APL home page   
       
   New Horizons --- NASA home page   
       
   Another strange thing about Pluto: Its sky collapses once a year. Around the   
   start of winter each Pluto year (248 Earth-years), it gets so cold on Pluto   
   that the atmosphere freezes. The molecules crystallize when the temperature   
   drops to around 32 K (-240 C), and the atmosphere falls to the ground as snow.   
       
   "This should occur again sometime in the next 30 years," says Stern. "Pluto is   
   headed away from the sun and winter is coming. We're hoping to reach Pluto   
   while the atmosphere is still thick."   
       
   New Horizons is primed to study the ice dwarf's atmosphere, if there still is   
   one. Stern isn't really worried: "The most recent observations show no   
   evidence of collapse. In fact the atmosphere seems to be getting thicker.   
   Pluto's summer heat is lingering."   
       
   Footnotes:   
       
   1. New Horizons is just the fifth probe to travel interplanetary space so far   
   from the sun. Voyager 1, Pioneer 10, and Pioneer 11 traveled this way as they   
   exited the solar system after Jupiter and Saturn flybys. But only Voyager 2   
   visited Uranus and Neptune. And no spacecraft has ever visited Pluto. NASA's   
   Dawn spacecraft is due to reach Ceres, a dwarf planet in the asteroid belt, in   
   February 2015, so it could become the first spacecraft to visit a dwarf   
   planet, if Dawn reaches Ceres before New Horizons reaches Pluto.   
   2. Geysers would be evidence for cryo-volcanism (i.e., volcanoes that spew icy   
   cold material rather than hot magma) on Pluto's surface. During a 1989 Neptune   
   flyby, Voyager 2 spotted dark streaks on Neptune's moon Triton that are   
   thought to have been produced by geysers spewing dirty, frozen nitrogen   
   particles. Pluto may exhibit something similar.   
       
   3. The spacecraft will "sleep" in electronic hibernation for much of the   
   cruise to Pluto. Operators will turn off all but the most critical electronic   
   systems and check in with the spacecraft once a year to check out the critical   
   systems, calibrate the instruments and perform course corrections, if   
   necessary. Between the in-depth checkouts, New Horizons will send back a   
   beacon signal each week to give operators an instant read on spacecraft   
   health. The entire spacecraft, drawing electricity from a single radioisotope   
   thermoelectric generator, operates on less power than a pair of 100-watt   
   household light bulbs.   
       
       
   Regards,   
       
   Roger   
      
   --- D'Bridge 3.64   
    * Origin: NCS BBS (1:3828/7)