Explorer 21 - Space launch mission detailed information
Explorer 21 21
4 OCT 1964
United States Air Force
Space Launch Complex 17A
Explorer 21 (IMP 2) was a solar-cell and chemical-battery powered spacecraft instrumented for interplanetary and distant magnetospheric studies of energetic particles, cosmic rays, magnetic fields, and plasmas.
Thor Delta C
American orbital launch vehicle family with Thor first stage and a delta second stage.