CERTIFICATE OF RE-ENTRYOrbital Register™ · by Orbital Radar™
Entry no.
1972-0361
EXPLORER 41 (IMP-5)
EXPLORER 41 (IMP-5) (NORAD 3990) re-entered Earth’s atmosphere on 23 December 1972, after 3 years, 6 months in orbit.
Official date
NORAD number
3990
International designator
1969-053A
Object type
Spacecraft
Country
United States
Launched
21 Jun 1969Vandenberg
Re-entered (UTC)
23 Dec 1972UTC calendar day
Time in orbit
3 years, 6 months1,281 days
How it ended
Re-entered (natural decay)
Latitude range
—
Mass
79 kg
Operator
GSFC
Built by
GSFC
Bus
IMP
Programme
IMP
Where it came down
Not on recordNo position was recorded for this re-entry. Its final orbit is not on record.
Life in orbit
3 years, 6 monthsEXPLORER 41 (IMP-5)’s lowest and highest points above Earth, week by week, from its tracking history.
From the same launch
1969-053
Entered in the Orbital Register™, founding volume, September 2026.
Record version 1 · No corrections · orbitalradar.com/register/1972-0361
© 2026 Orbital Radar. Cite this entry by its number; the register itself may not be copied.
Record version 1 · No corrections · orbitalradar.com/register/1972-0361
© 2026 Orbital Radar. Cite this entry by its number; the register itself may not be copied.