A Laser Message from Space  
    
  June 18, 2014:  Anyone who remembers dialup internet can sympathize with the  
  plight of NASA mission controllers.  Waiting for images to arrive from deep  
  space, slowly downloading line by line, can be a little like the World Wide  
  Web of the 1990s.  Patience is required.  
    
  A laser on the International Space Station (ISS) could change all that.  On  
  June 5th, 2014, the ISS passed over the Table Mountain Observatory in  
  Wrightwood, California, and beamed an HD video to researchers waiting  
  below.  
  Unlike normal data transmissions, which are encoded in radio waves, this one  
  came to Earth on a beam of light.  
    
  "It was incredible to see this magnificent beam of light arriving from our  
  tiny payload on the space station," says Matt Abrahamson, who manages the  
  Optical Payload for Lasercomm Science at NASA's Jet Propulsion Laboratory.  
    
  http://youtu.be/S8uL8ox-SlQ  
    
  The bright spot in this telescopic image of the ISS is the OPALS laser beam  
  transmitting HD video to Earth. A new ScienceCast video explains how it  
  works.  Play it  
    
  Better known as "OPALS," the experimental laser device was launched to the  
  space station onboard a Space-X Dragon spacecraft in the spring of 2014. Its  
  goal is to explore the possibility of high-bandwidth space communications  
  using light instead of radio waves.  If successful, researchers say OPALS  
  would be like an upgrade from dial-up to DSL, achieving data rates 10 to 1,  
  000  
  times higher than current space communications.  
    
  So far so good.  
    
  The entire transmission on June 5th lasted 148 seconds and achieved a  
  maximum  
  data rate of 50 megabits per second. It took OPALS 3.5 seconds to transmit a  
  single copy of the video message, which would have taken more than 10  
  minutes  
  using traditional downlink methods. The message was sent multiple times  
  during  
  the transmission.  
    
  Abrahamson says "the video is an homage to the first output of any standard  
  computer program: 'Hello, World.'"  
    
  https://www.youtube.com/watch?v=hPOstCZKycI  
    
  Click on the image to play the complete "Hello World" video.  
    
  Because the space station whips around Earth at 17,500 mph, "laser-tagging"  
  a  
  telescope on the fast-moving ground below can be tricky. To accomplish the  
  precision tag-up, a laser at the ground station illuminated the station.  
  OPALS  
  responded by sending its own 2.5 watt encoded laser signal right back in the  
  same direction, carrying the HD video. During the 148-second transmission,  
  OPALS maintained pointing to the ground station within 0.01 degrees while  
  tracking at speeds up to 1 degree per second.  
    
  "NASA missions collect an enormous amount of data out in space," says  
  Abrahamson. "Laser communications is a faster alternative for getting those  
  data to the ground."  
    
  "With this demonstration, we're paving the way for the future of  
  communications to and from space."  
    
  Credits:  
  Author: Dr. Tony Phillips | Production editor: Dr. Tony Phillips | Credit:  
  Science@NASA  
    
  Web Links:  OPALS -- home page at JPL   OPALS --information from NASA HQ  
    
    
  Regards,  
    
  Roger  
    
  --- D'Bridge 3.99  
   * Origin: NCS BBS - Houma, LoUiSiAna (1:3828/7)