Home›Maneuver Tracker›Close Approaches›COSMOS 2143 ⟷ SL-14 R/B
HighProximity
RussiaCOSMOS 2143NORAD 21299 · launched May 1991Military payload
3.55kmPredicted miss distance
RussiaSL-14 R/BNORAD 19791 · launched Feb 1989Rocket body
Final forecastFinal forecast, made 8 min before the pass.
Closest approach11 Nov 202607:54 UTC
Relative speed14.11 km/sat the closest approach
Altitude1,423 kmlow Earth orbit
Last confirmed11 Nov07:46 UTC · final forecast
Track COSMOS 2143Track SL-14 R/BAll approaches
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RU COSMOS 2143 and RU SL-14 R/B were predicted to reach a closest approach of 3.55 km at 2026-11-11 07:54 UTC, at a relative speed of 14.11 km/s. Final forecast, made 8 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 mattersOne side of this pass cannot maneuver, so any avoidance decision rests with the other operator. Screening continues as new element sets arrive.

The Two Objects

Dossiers from the satellite directory
COSMOS 2143Payload
NORAD 21299
CountryCIS
Launched1991-05-16
OrbitLEO · 1,396 × 1,418 km
COSPAR1991-033A
Maneuver capableUnknown
Profile →Globe →
SL-14 R/BR/B
NORAD 19791
CountryCIS
Launched1989-02-10
OrbitLEO · 1,418 × 1,471 km
COSPAR1989-009G
Maneuver capableNo
Spent rocket stage: uncontrolled, tracked by the public catalogue.
Profile →Globe →

Where This Happens

Altitude context
DEBRIS BELT 700–1000 KM2006001,0001,5002,000 kmTHIS PASS · 1423 KMISS 420Starlink 550

At 1423 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 2143 ⟷ SL-14 R/B
2026-11-11 07:543.55 km Final forecast14.11 km/s1,423 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 Nothing is overwritten: a withdrawn forecast keeps its figure, with the newer check beside it, and the best estimate after the pass is a row of its own.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
10 Nov 22:02 UTC3.55 km Forecast11 Nov 07:54 UTC10 Nov 05:28 UTCRe-check
10 Nov 21:42 UTC5.88 km Forecast11 Nov 07:54 UTC10 Nov 05:28 UTCScreen

These Objects Elsewhere

Other screened approaches · 7 days
2.44 km11-08 23:25 UTC
COSMOS 2143GLOBALSTAR M082
3.71 km11-07 22:17 UTC
COSMOS 2143GLOBALSTAR M096
3.82 km11-07 22:15 UTC
COSMOS 2143COSMOS 81

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 →