CERTIFICATE OF RE-ENTRYOrbital Register™ · by Orbital Radar™
Entry no.
1981-0287
EXPLORER 55 (AE-5)
EXPLORER 55 (AE-5) (NORAD 8440) re-entered Earth’s atmosphere on 10 June 1981, after 5 years, 6 months in orbit.
Official date
NORAD number
8440
International designator
1975-107A
Object type
Spacecraft
Country
United States
Launched
20 Nov 1975Cape Canaveral
Re-entered (UTC)
10 Jun 1981Recorded time 13:57 UTC
Time in orbit
5 years, 6 months2,029 days
How it ended
Re-entered (natural decay)
Latitude range
19.6°N to 19.6°SFinal inclination 19.6°
Mass
720 kg
Operator
GSFC
Built by
RCA/East Windsor
Bus
AE-C
Programme
Explorer AE
Where it came down
Latitude band its orbit allowedExact position not recorded
No position was recorded for this re-entry. Its final orbit, inclined at 19.6°, allowed a re-entry anywhere between 19.6°N and 19.6°S.
Life in orbit
5 years, 6 monthsEXPLORER 55 (AE-5)’s lowest and highest points above Earth, week by week, from its tracking history.
From the same launch
1975-107
Entered in the Orbital Register™, founding volume, September 2026.
Record version 1 · No corrections · orbitalradar.com/register/1981-0287
© 2026 Orbital Radar. Cite this entry by its number; the register itself may not be copied.
Record version 1 · No corrections · orbitalradar.com/register/1981-0287
© 2026 Orbital Radar. Cite this entry by its number; the register itself may not be copied.