Home›Maneuver Tracker›Close Approaches›COSMOS 2158 ⟷ COSMOS 940
MediumProximity
RussiaCOSMOS 2158NORAD 21729 · launched Sep 1991Military payload
5.14kmPredicted miss distance
RussiaCOSMOS 940NORAD 10286 · launched Aug 1977Military payload
Final forecastFinal forecast, made 19 min before the pass.
After the passBest estimate, from the orbit data published nearest its time: 5.15 km at 7 Nov 18:30 UTC.
Closest approach7 Nov 202618:30 UTC
Relative speed12.43 km/sat the closest approach
Altitude1,420 kmlow Earth orbit
Last confirmed7 Nov18:11 UTC · final forecast
Track COSMOS 2158Track COSMOS 940All approaches
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RU COSMOS 2158 and RU COSMOS 940 were predicted to reach a closest approach of 5.14 km at 2026-11-07 18:30 UTC, at a relative speed of 12.43 km/s. Final forecast, made 19 min before the pass. Best estimate after the pass, from the orbit data published nearest its time: 5.15 km at 7 Nov 18:30 UTC. 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 2158Payload
NORAD 21729
CountryCIS
Launched1991-09-28
OrbitLEO · 1,401 × 1,411 km
COSPAR1991-068B
Maneuver capableUnknown
Profile →Globe →
COSMOS 940Payload
NORAD 10286
CountryCIS
Launched1977-08-24
OrbitLEO · 1,393 × 1,462 km
COSPAR1977-079B
Maneuver capableUnknown
Profile →Globe →

Where This Happens

Altitude context
DEBRIS BELT 700–1000 KM2006001,0001,5002,000 kmTHIS PASS · 1420 KMISS 420Starlink 550

At 1420 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 2158 ⟷ COSMOS 940
2026-11-07 18:305.14 km Final forecast · after: 5.15 km12.43 km/s1,420 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
12 Nov 02:38 UTC5.15 km Best estimate7 Nov 18:30 UTC7 Nov 21:37 UTCBest estimate
7 Nov 12:51 UTC5.14 km Forecast7 Nov 18:30 UTC7 Nov 06:40 UTCRe-check
7 Nov 09:18 UTC5.14 km Forecast7 Nov 18:30 UTC6 Nov 20:48 UTCRe-check
7 Nov 00:14 UTC5.16 km Forecast7 Nov 18:30 UTC6 Nov 18:39 UTCRe-check
6 Nov 23:54 UTC5.46 km Forecast7 Nov 18:30 UTC6 Nov 18:39 UTCScreen

These Objects Elsewhere

Other screened approaches · 7 days
4.08 km11-07 18:31 UTC
COSMOS 2301COSMOS 940
6.30 km11-07 16:40 UTC
COSMOS 2158COSMOS 1830
9.40 km11-11 21:53 UTC
COSMOS 2118COSMOS 940

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 →