Satellite · NORAD 889 · COSPAR 1964-060A
EXPLORER 21 (IMP-2)
- Operator United States
- Constellation —
- Country United States
Altitude now
—
object decayed
Velocity
—
Inclination
33.72°
Period
1.4 d
2,080.3 min
Perigee
917km
Apogee
94,291km
orbit unavailableNo orbital element set on file — decayed 30 Jan 1966.· Metadata updated 10 h ago
Live position
Live position
Live position unavailable — this object re-entered the atmosphere on 30 Jan 1966 and is no longer tracked.
Mission
Mission & classification
- Mission type derived
- Unknown
- Object type
- Payload
- SATCAT ops status
- Decayed [D]
- Radar cross-section
- —
CelesTrak groups
Not listed in any CelesTrak group.
Aliases
- EXPLORER 21 (IMP-2)Celestrak Satcat
Ownership
Operator & country
- Operator
- —
- SATCAT owner code
- US · United States
- Country
- United States US
Launch
Launch
- Launch date
- 04 Oct 1964
- COSPAR launch id
- 1964-060
Objects from the same launch
No other catalogued object is linked to this launch.
Change log
History
No changes recorded since first ingestion on 11 Sept 2026 18:54 UTC. Status, orbit class, name and ownership changes are logged here as sources are re-ingested.
Regulatory
UN registration
Transparency
Sources & provenance
No source is linked to this record yet — the catalogue row exists but no provenance entry has been written for it.
Field provenance
No field-level provenance recorded.
Timeline
Events
No events detected for this object yet. Launches, decays and orbit changes are generated by the derived-analytics connector.
Reference
Identifiers
- NORAD catalogue number
- 889
- COSPAR / international designator
- 1964-060A
- SatelliteIndex id
- sat_01M28X3JJDHZBK46B4JZ202Y5Z
- Canonical slug
- explorer-21-imp-2-889
Orbit class, mission type and constellation membership are derived by SatelliteIndex (Unknown) — see the methodology. Positions are propagated estimates, not tracking measurements; never use them for conjunction assessment.