Curiosity, the Stunt Double   
       
   Feb. 24, 2012:  With a pair of bug-eyes swiveling on a stalk nearly 8 feet off   
   the ground, the 6-wheeled, 1800-lb Mars rover Curiosity doesn't look much like   
   a human being.  Yet, right now, the mini-Cooper-sized rover is playing the   
   role of stunt double for NASA astronauts.   
       
   "Curiosity is riding to Mars in the belly of a spacecraft, where an astronaut   
   would be," explains Don Hassler of the Southwest Research Institute in   
   Boulder, Colorado.  "This means the rover experiences deep-space radiation   
   storms in the same way that a real astronaut would."   
       
       
   Curiosity doesn't look much like a human being, but the rover turns out to be   
   an excellent stunt double for real astronauts. [video]   
   Indeed, on Jan. 27th, 2012, Curiosity's spacecraft was hit by the most intense   
   solar radiation storm since 2005.   The event began when sunspot AR1402   
   produced an X2-class solar flare. (On the "Richter Scale of Solar Flares,"   
   X-flares are the most powerful kind.)  The explosion accelerated a fusillade   
   of protons and electrons to nearly light speed; these subatomic bullets were   
   guided by the sun's magnetic field almost directly toward Curiosity.   
       
   When the particles hit the outer walls of the spacecraft, they shattered other   
   atoms and molecules in their path, producing a secondary spray of radiation   
   that Curiosity both absorbed and measured.   
       
   "Curiosity was in no danger," says Hassler.  "In fact, we intended all along   
   for the rover to experience these storms en route to Mars."   
       
       
   A photo of the Radiation Assessment Detector (RAD) in the laboratory. [more]   
   Unlike previous Mars rovers, Curiosity is equipped with a Radiation Assessment   
   Detector.  The instrument, nicknamed "RAD," counts cosmic rays, neutrons,   
   protons and other particles over a wide range of biologically-interesting   
   energies. RAD's prime mission is to investigate the radiation environment on   
   the surface of Mars, but researchers have turned it on early so that it can   
   also probe the radiation environment on the way to Mars as well.   
       
   Curiosity's location inside the spacecraft is key to the experiment.   
       
   "We have a pretty good idea what the radiation environment is like outside,"   
   says Hassler, who is the principal investigator for RAD.  "Inside the   
   spacecraft, however, is still a mystery."   
       
   Even supercomputers have trouble calculating exactly what happens when   
   high-energy cosmic rays and solar energetic particles hit the walls of a   
   spacecraft.  One particle hits another; fragments fly; the fragments   
   themselves crash into other molecules.   
       
   "It's very complicated.  Curiosity is giving us a chance to actually measure   
   what happens."   
       
   Even when the sun is quiet, Curiosity is bombarded by a slow drizzle of cosmic   
   rays-high-energy particles accelerated by distant black holes and supernova   
   explosions.  In the aftermath of the Jan. 27th X-flare, RAD detected a surge   
   of particles several times more numerous than the usual cosmic ray counts.   
   Hassler's team is still analyzing the data to understand what it is telling   
   them about the response of the spacecraft to the storm.   
       
   More X-flares will help by adding to the data set. Hassler expects the sun to   
   cooperate, because the solar cycle is trending upward toward a maximum   
   expected in early 2013.   
       
   As of February 2012, "we still have 6 months to go before we reach Mars.   
   That's plenty of time for more solar storms."   
       
   A stunt double's work is never done.   
       
       
   Author:Dr. Tony Phillips| Production editor: Dr. Tony Phillips | Credit:   
   Science@NASA   
       
   More Information   
   RAD Measures Radiation from Solar Storm -- SwRI press release   
       
   Curiosity and the Solar Storm -- Science@NASA   
       
   Follow Curiosity to Mars on Twitter at http://www.twitter.com/marscuriosity   
   and on Facebook at: http://www.facebook.com/marscuriosity .   
       
   Mars-Bound Rover Begins Research in Space -- NASA press release   
       
   Mars Science Lab -- Curiosity's home page   
       
   The Strange Attraction of Gale Crater -- Science@NASA   
       
   Credits: The Mars Science Lab mission is managed by JPL, a division of the   
   California Institute of Technology in Pasadena, for NASA's Science Mission   
   Directorate in Washington. The rover was designed, developed and assembled at   
   JPL. NASA's Launch Services Program at the Kennedy Space Center in Florida   
   managed the launch. NASA's Space Network provided space communication services   
   for the launch vehicle. NASA's Deep Space Network will provide spacecraft   
   acquisition and mission communication.   
       
       
   Regards,   
       
   Roger   
      
   --- D'Bridge 3.75   
    * Origin: NCS BBS (1:3828/7)