Mariner 10 radiation. The plasma experiment's goal was to study the ionized gases (plasma) of the solar wind, the temperature and density of its electrons, and how the planets affected the velocity of the plasma stream. The experiment contained two components, facing in opposite directions. The Scanning Electrostatic Analyzer was aimed toward the Sun, and could detect positive ions and electrons, which were separated by a set of three concentric hemispherical plates. The Scanning Electron Spectrometer was aimed away from the Sun, and detected only electrons, using just one hemispherical plate. The instruments could be rotated about 60 degrees to either side.
Sun Stream not compete again. In their book, "A Century of Champions", based on the Timeform rating system, John Randall and Tony Morris rated Sun Stream a "superior" winner of the 1000 Guineas and Oaks and the twenty-fifth best filly trained in Britain or Ireland in the 20th century. Sun Stream retired from racing to become a broodmare at her owner's stud. She produced four minor winners, but nothing of top class. Through her daughter Riviera, she was the female ancestor of the Champion Hurdler Collier Bay. Sun Stream was euthanised in January 1959. Sun Stream Sun Stream (1942 – January 1959)