Home›Maneuver Tracker›Close Approaches›COSMOS 2129 ⟷ COSMOS 1797
MediumProximity
RussiaCOSMOS 2129NORAD 21104 · launched Feb 1991Military payload
5.42kmPredicted miss distance
RussiaCOSMOS 1797NORAD 17141 · launched Nov 1986Military payload
Final forecastFinal forecast, made 17 min before the pass.
Closest approach22 Oct 202605:41 UTC
Relative speed6.77 km/sat the closest approach
Altitude1,440 kmlow Earth orbit
Last confirmed22 Oct05:24 UTC · final forecast
Track COSMOS 2129Track COSMOS 1797All approaches
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RU COSMOS 2129 and RU COSMOS 1797 were predicted to reach a closest approach of 5.42 km at 2026-10-22 05:41 UTC, at a relative speed of 6.77 km/s. Final forecast, made 17 min before the pass. Miss distance and time of closest approach are computed by propagating the latest published orbital elements for both objects, and each pass is re-checked every 20 minutes as new element sets are published. See the Satellite Maneuver Tracker for the live picture and space situational awareness for context.

Why it mattersBoth objects are catalogued as payloads. Screening continues as new element sets arrive; operators act on their own conjunction data.

The Two Objects

Dossiers from the satellite directory
COSMOS 2129Payload
NORAD 21104
CountryCIS
Launched1991-02-12
OrbitLEO · 1,429 × 1,468 km
COSPAR1991-009E
Maneuver capableUnknown
Profile →Globe →
COSMOS 1797Payload
NORAD 17141
CountryCIS
Launched1986-11-21
OrbitLEO · 1,444 × 1,472 km
COSPAR1986-092D
Maneuver capableUnknown
Profile →Globe →

Where This Happens

Altitude context
DEBRIS BELT 700–1000 KM2006001,0001,5002,000 kmTHIS PASS · 1440 KMISS 420Starlink 550

At 1440 km this pass sits in low Earth orbit. Objects here stay up for decades: there is too little atmospheric drag to clean the band naturally. Why crowded bands matter →

History Between This Pair

1 predicted pass under 10 km
Pair history · COSMOS 2129 ⟷ COSMOS 1797
2026-10-22 05:415.42 km Final forecast6.77 km/s1,440 kmShown above

Repeat encounters are common for objects in near-intersecting orbital planes. Each pass is re-screened as fresh element sets arrive; "Final forecast" means the screening still predicted it within 45 minutes of its time, "Not re-confirmed" means later screening stopped finding it.

Forecast Record

Every figure published for the pass shown above, newest first. Nothing is overwritten: a withdrawn forecast keeps its figure, with the newer check beside it, and the best estimate after the pass is a row of its own.
Computed · figure · predicted time · orbit data · by
22 Oct 02:04 UTC5.42 km Forecast22 Oct 05:41 UTC21 Oct 10:14 UTCRe-check
21 Oct 13:30 UTC5.41 km Forecast22 Oct 05:41 UTC21 Oct 06:20 UTCRe-check
21 Oct 09:46 UTC5.37 km Forecast22 Oct 05:41 UTC20 Oct 21:02 UTCRe-check
21 Oct 09:27 UTC8.20 km Forecast22 Oct 05:41 UTC20 Oct 21:02 UTCScreen

These Objects Elsewhere

Other screened approaches · 7 days
2.55 km10-16 14:48 UTC
COSMOS 2129COSMOS 1523
4.45 km10-23 06:33 UTC
COSMOS 2129COSMOS 619
4.80 km10-22 16:10 UTC
COSMOS 2129THORAD DELTA 1 DEB

How These Numbers Are Computed

Miss distance and TCA come from propagating the latest published orbital elements for both objects and searching for the minimum separation over the screening window. Element sets carry kilometre-scale uncertainty, so figures here describe a close pass, not a collision prediction; a change in either object's published elements re-computes the pass automatically. What is a conjunction? → How conjunction assessment works →

Cite this encounter: Orbital Radar — “COSMOS 2129 ⟷ COSMOS 1797: 5.42 km predicted close approach”, https://orbitalradar.com/conjunction/17141-21104 (accessed 2026-10-22).