CERTIFICATE OF RE-ENTRYOrbital Register™ · by Orbital Radar™
Entry no.
1965-0404
EXPLORER 18 (IMP-1)
EXPLORER 18 (IMP-1) (NORAD 693) re-entered Earth’s atmosphere on 30 December 1965, after 2 years, 1 month in orbit.
Official date
NORAD number
693
International designator
1963-046A
Object type
Spacecraft
Country
United States
Launched
27 Nov 1963Cape Canaveral
Re-entered (UTC)
30 Dec 1965UTC calendar day
Time in orbit
2 years, 1 month764 days
How it ended
Re-entered (natural decay)
Latitude range
—
Mass
63 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
2 years, 1 monthEXPLORER 18 (IMP-1)’s lowest and highest points above Earth, week by week, from its tracking history.
Entered in the Orbital Register™, founding volume, September 2026.
Record version 1 · No corrections · orbitalradar.com/register/1965-0404
© 2026 Orbital Radar. Cite this entry by its number; the register itself may not be copied.
Record version 1 · No corrections · orbitalradar.com/register/1965-0404
© 2026 Orbital Radar. Cite this entry by its number; the register itself may not be copied.