Cosmic Ray Ionization
An ion chamber and a GM tube were used to determine uncontaminated cosmic-ray flux in interplanetary space. The experiment measured the average omindirectional flux of corpuscular radiation and the average specific flux between earth and Mars and in the vicinity of Mars. The two companion instruments measured the ionization caused by charged particles and the number of particles in the range above 0.5 MeV for electrons and above 10 MeV for protons. The GM tube was mounted away from the main body of the spacecraft so that at the tube the spacecraft subtended 14 percent of 4 pi ster, not including the thin solar panels. The instrumentation functioned well, and ionization data were received until the GM tube became saturated and failed on March 3, 1965. The ion chamber failed shortly afterwards, and thus, no data were obtained in the vicinity of Mars.