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Launch SuccessfulUnited States Air Force
Thor Delta C: Explorer 21
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.
Sunday, 4 October 1964
Mission Data
🇺🇸United States Air ForceEst. 1947
Launch VehicleThor Delta C
Vehicle FamilyThor
Vehicle Record8 of 10 launches (80%)
Provider TypeGovernment
Agency Record972 successes / 106 failures (90%)
Success Streak68 consecutive
Mission TypeAstrophysics
Target OrbitElliptical Orbit
Launch PadSpace Launch Complex 17A
Location🇺🇸 Cape Canaveral SFS, FL, USA USA
Orbital Launches This Year#70
Agency Launches This Year#39
Launches From This Pad145
Launches From This Site1,132
Status Note
The launch vehicle successfully inserted its payload(s) into the target orbit(s).
About Thor Delta C
American orbital launch vehicle family with Thor first stage and a delta second stage.
Launch Site
Space Launch Complex 17A · 28.4472°N 80.5650°W
Launch data from Launch Library 2 by The Space Devs.