A Giant Among Earth Satellites   
       
   Sept. 24, 2014: The International Space Station has been called a stepping   
   stone to other worlds.   
       
   NASA hasn't forgotten, however, that the behemoth space station is also on the   
   doorstep of Earth.   
       
   "We're seeing the space station come into its own as an Earth-observing   
   platform," says Julie Robinson, chief scientist for the International Space   
   Station Program. "It has a different orbit than other Earth-observing   
   satellites. It's closer to Earth, and it sees Earth at different times of day   
   with a different schedule."   
       
   http://www.youtube.com/watch?v=jn8yezfH7HM&feature=youtu.be   
       
   A new ScienceCast video explains how the International Space Station has   
   become the largest of all Earth-observing satellites. Play it   
       
   In short, the space station offers something unique to the study of our home   
   planet.   
       
   Sometimes astronauts in low Earth orbit to see what regular satellites do   
   not.  In May 2013 for example, astronauts on board the International Space   
   Station photographed a fresh eruption of the Pavlof Volcano in the Aleutian   
   Islands. Their oblique perspective revealed the three dimensional structure of   
   the ash plume, which was only 20,000 feet high, but many times longer.   
   Down-looking satellites could not get the same kind of 3D information.   
       
   Low Earth orbit turns out to be a great place to study the planet below. In   
   recent years astronauts trained to photograph Earth have gathered data on   
   desert dust, coral reefs, urban growth, pollution, glaciers, hurricanes,   
   lightning, river deltas, volcanic plumes, Northern and Southern Lights and   
   much more.   
       
   Now, however, NASA is taking the space station's Earth-observing capabilities   
   to a whole new level. Before the end of the decade, six NASA Earth science   
   instruments will be mounted to the station to help scientists study our   
   changing planet.   
       
   The upgrades began this month: On Sept. 20th, a SpaceX resupply rocket blasted   
   off from Cape Canaveral carrying the first NASA Earth-observing instrument to   
   be mounted on the exterior of the space station: ISS-RapidScat will monitor   
   ocean winds for climate research, weather predictions and hurricane science.   
       
   http://www.nasa.gov/multimedia/imagegallery/image_feature_2515.html   
       
   Learn more about ISS observations of the erupting Pavlof volcanoNext up is the   
   Cloud-Aerosol Transport System--"CATS' for short--a laser radar that can   
   measure clouds along with airborne particles such as pollution, mineral dust,   
   and smoke. CATS will follow ISS-RapidScat on another SpaceX flight targeted   
   for December.   
       
   Two more Earth science instruments are slated to launch in 2016. First, SAGE   
   III will measure ozone and other gases in the upper atmosphere to help   
   scientists assess how the ozone layer is recovering. Second, the Lightning   
   Imaging Sensor will monitor thunderstorm activity around the globe.   
       
   Those instruments are already built and ready to fly.  In July, NASA selected   
   proposals for two new instruments: The Global Ecosystem Dynamics   
   Investigation, "GEDI", and the ECOsystem Spaceborne Thermal Radiometer   
   Experiment on Space Station, "ECOSTRESS", will give scientists new ways to   
   observe how forests and ecosystems are affected by climate change. Both will   
   be completed before the end of the decade.   
       
   Stephen Volz, associate director of flight programs in the Earth Science   
   Division at NASA Headquarters explains the rapid pace of new sensors: "With   
   the space station we don't have to build a whole new spacecraft to gather new   
   data -- it's already there. Designing instruments for the space station also   
   gives us a chance to do high-risk, high-return instruments in a relatively   
   economical way."   
       
   The biggest spacecraft in Earth orbit is now paying serious attention to our   
   home planet.  For more news from low-Earth orbit, stay tuned to    
   cience.nasa.gov   
       
   Credits:   
   Author: Dr. Tony Phillips |  Production editor: Dr. Tony Phillips | Credit:   
   Science@NASA   
       
   More information about ISS Earth Science Instruments   
       
   ISS-Rapidscat   
       
   Cloud-Aerosol Transport System   
       
   Global Ecosystem Dynamics Investigation   
       
   SAGE III   
       
       
   Regards,   
       
   Roger   
      
   --- D'Bridge 3.99   
    * Origin: NCS BBS - Houma, LoUiSiAna (1:3828/7)