CERTIFICATE OF RE-ENTRYOrbital Register™ · by Orbital Radar™
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Entry no.
1968-0179

EXPLORER 28 (IMP-3)

EXPLORER 28 (IMP-3) (NORAD 1388) re-entered Earth’s atmosphere on 4 July 1968, after 3 years, 1 month in orbit.

Official date
NORAD number
1388
International designator
1965-042A
Object type
Spacecraft
Country
United States
Launched
29 May 1965Cape Canaveral
Re-entered (UTC)
4 Jul 1968UTC calendar day
Time in orbit
3 years, 1 month1,132 days
How it ended
Re-entered (natural decay)
Latitude range
—
Mass
59 kg
Operator
GSFC
Built by
GSFC
Bus
IMP
Programme
IMP

Where it came down

Not on record

No position was recorded for this re-entry. Its final orbit is not on record.

Life in orbit

3 years, 1 month

Also ended on 4 Jul 1968

2 entries
1968-0180COSMOS 2291968-0181SL-3 R/B
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Entered in the Orbital Register™, founding volume, September 2026.
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