MISSION OVERVIEW
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.
LAUNCH DETAILS
VEHICLE
Thor Delta CAGENCY
United States Air ForceMISSION
Explorer 21
MISSION TYPE
Astrophysics
TARGET ORBIT
Elliptical Orbit
LAUNCH PAD
Space Launch Complex 17ALAUNCH SITE
Cape Canaveral SFS, FL, USACOUNTRY
USA
LAUNCH TIME VERIFICATION
CONFIRMEDPrecision: Minute
LAUNCH LIBRARY 2 PRIMARY
API ID: 40378bed-00c8-4cbf-916e-540b40eaa8b9
Reported date: Oct 4, 1964 at 03:45 UTC
Last synced: 8 minutes ago
This launch date and time are confirmed by the launch provider. Countdown is active.
LAUNCH MAP
PAD WEATHER
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VEHICLE — Thor Delta C →
MANUFACTURER
McDonnell Douglas
VARIANT
Delta C
FLIGHTS
10
SUCCESSES
8
SUCCESS RATE
80%
American orbital launch vehicle family with Thor first stage and a delta second stage.
FREQUENTLY ASKED QUESTIONS
When is the Thor Delta C | Explorer 21 launch?
The Thor Delta C | Explorer 21 is scheduled for Sunday, October 4, 1964 at 3:45 AM UTC. This is the NET (No Earlier Than) time and may be subject to change. Current status: SUCCESS.
What rocket is being used for Explorer 21?
The Thor Delta C | Explorer 21 mission uses the Thor Delta C rocket, manufactured by McDonnell Douglas. The Thor Delta C has flown 10 times with a 80% success rate.
Where is the Thor Delta C | Explorer 21 launching from?
The launch takes place from Space Launch Complex 17A at Cape Canaveral SFS, FL, USA.
What orbit is Explorer 21 going to?
The Explorer 21 mission is targeting Elliptical Orbit.
Who is launching Explorer 21?
The Thor Delta C | Explorer 21 is operated by United States Air Force.
Can I watch the Thor Delta C | Explorer 21 launch live?
Yes. Visit the launch detail page on Space Launch Live for embedded YouTube webcasts, replay videos, and links to live coverage from SpaceX, NASA, NASASpaceflight, and other channels.
LAUNCH TIMELINE
Mar 28, 2026 20:13 UTC
Launch added to tracker
Imported from Launch Library 2 API
Mar 28, 2026 20:13 UTC
Launch date set: Oct 4, 1964 at 03:45 UTC
NET (No Earlier Than) confirmed by United States Air Force
Mar 28, 2026 20:13 UTC
Launch completed successfully
Updated via Launch Library 2
LIVE DATA SOURCES
Last data sync: 8 minutes ago
●Launch Library 28 minutes ago
Launch ID: 40378bed-00c8-4cbf-916e-540b40eaa8b9
●Open-Meteo Weather17 hours ago
Pad weather at 28.45, -80.57
