Radiation Dosimeters Developed for SNAP 10A Flight Test

LMSC provided five sets of radiation dosimeters on the first SNAP 10A (reactor-thermoelectric converter) power system flight test to measure the reactor leakage radiations throughout the SNAPSHOT Agena orbital vehicle. Fast neutron and thermal neutron flux and gamma ray dose rate measurements were made. The radiation measurements were required for in flight analysis of the reactor steady state leakage radiation effects on the SNAPSHOT orbital power conversion, guidance, command and telemetry equipment. This solid state equipment was specially "radiation hardened" to withstand a year\´s exposure to the reactor radiations in the space environment. The paper covers a description of the dosimeters, principles of operation of each type of instrument, development, ground testing, calibration, vehicle integration and flight test results. Flight data of the reactor startup are presented in direct computer printout form showing the quality of the nuclear measurements obtained from the dosimeter orbital telemetry system. A brief description of the SNAPSHOT vehicle nuclear distributions developed from the flight measurements is also given.