CERTIFICATE OF RE-ENTRYOrbital Register™ · by Orbital Radar™
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Entry no.
1981-0309

EXPLORER 39 (ADI-3)

EXPLORER 39 (ADI-3) (NORAD 3337) re-entered Earth’s atmosphere on 22 June 1981, after 12 years, 10 months in orbit.

Official date
NORAD number
3337
International designator
1968-066A
Object type
Spacecraft
Country
United States
Launched
8 Aug 1968Vandenberg
Re-entered (UTC)
22 Jun 1981UTC calendar day
Time in orbit
12 years, 10 months4,701 days
How it ended
Re-entered (natural decay)
Latitude range
80.5°N to 80.5°SFinal inclination 80.5°
Mass
16 kg
Operator
NASA LaRC
Built by
Schjeldahl
Bus
12' Sphere
Programme
Explorer AD

Where it came down

Latitude band its orbit allowed
Exact position not recorded

No position was recorded for this re-entry. Its final orbit, inclined at 80.5°, allowed a re-entry anywhere between 80.5°N and 80.5°S.

Life in orbit

12 years, 10 months

EXPLORER 39 (ADI-3)’s lowest and highest points above Earth, week by week, from its tracking history.

Also ended on 22 Jun 1981

8 entries
1981-0312Kosmos-1186 SS 131981-0313Kosmos-1186 SS 161981-0310THORAD AGENA D DEB1981-0311SALYUT 6 DEB1981-0314SL-6 DEB1981-0315SL-4 DEB1981-0316SL-4 DEB1981-0317COSMOS 1249 DEB (ANTENNA

From the same launch

1968-066
In orbitInjun 5
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Entered in the Orbital Register™, founding volume, September 2026.
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