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 were rescheduled to new dates and venues, often at short notice, and all five of the Classics were run at Newmarket. As a two-year-old in 1944, Sun Stream was among the best of her generation. She won the Bedford Stakes over five furlongs at Newmarket in spring and then moved up in class for the Queen Mary Stakes in June. The race, traditionally part of the Royal Ascot meeting, was run at Newmarket from 1941 to 1944. Ridden by Harry Wragg, she won the race at odds of 100/30. In autumn, Sun Stream ran in the six furlong Cheveley Park