Explorer 21 (IMP-2 / Interplanetary Monitoring Platform B), a NASA magnetospheric and solar-wind research satellite. Thor Delta C from Cape Canaveral launched it on 4 October 1964 into a lower-than-planned highly elliptical orbit after a partial upper-stage shortfall; it still returned useful data into 1965.
- Outcome
- Success
- Orbit
- Elliptical
- Elliptical orbit
- Payload to orbit
- 62 kg
- Flight
- 2nd
- of 10 Thor Delta C flights
- Date and time
- 4 October 1964, 03:45 UTC
- Rocket
- Thor Delta C
- Builder
- McDonnell Douglas
- Launch site
- Space Launch Complex 17A, Cape Canaveral SFS, FL, USA
- Payload
- Astrophysics
- International designator
- 1964-060
- Launches in 1964
- 70th of 100
See it in orbit
Space Atlas shows the satellites and rocket stages from this launch in 3D.
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