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HighProximity
RussiaCOSMOS 2170NORAD 21784 · launched Nov 1991Military payload
3.18kmPredicted miss distance
RussiaSL-8 R/BNORAD 7426 · launched Aug 1974Rocket body
Final forecastFinal forecast, made 12 min before the pass.
After the passBest estimate, from the orbit data published nearest its time: 3.18 km at 25 Oct 09:22 UTC.
Closest approach25 Oct 202609:22 UTC
Relative speed13.33 km/sat the closest approach
Altitude1,417 kmlow Earth orbit
Last confirmed25 Oct09:10 UTC · final forecast
Track COSMOS 2170Track SL-8 R/BAll approaches
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RU COSMOS 2170 and RU SL-8 R/B were predicted to reach a closest approach of 3.18 km at 2026-10-25 09:22 UTC, at a relative speed of 13.33 km/s. Final forecast, made 12 min before the pass. Best estimate after the pass, from the orbit data published nearest its time: 3.18 km at 25 Oct 09:22 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 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 2170Payload
NORAD 21784
CountryCIS
Launched1991-11-12
OrbitLEO · 1,410 × 1,415 km
COSPAR1991-077F
Maneuver capableUnknown
Profile →Globe →
SL-8 R/BR/B
NORAD 7426
CountryCIS
Launched1974-08-29
OrbitLEO · 1,352 × 1,421 km
COSPAR1974-069B
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 · 1417 KMISS 420Starlink 550

At 1417 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 2170 ⟷ SL-8 R/B
2026-10-25 09:223.18 km Final forecast13.33 km/s1,417 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
27 Oct 21:23 UTC3.18 km Best estimate25 Oct 09:22 UTC25 Oct 23:02 UTCBest estimate
25 Oct 08:51 UTC3.18 km Forecast25 Oct 09:22 UTC24 Oct 04:03 UTCRe-check
25 Oct 08:34 UTC6.39 km Forecast25 Oct 09:22 UTC24 Oct 04:03 UTCScreen

These Objects Elsewhere

Other screened approaches · 7 days
201 m10-22 09:36 UTC
COSMOS 1998SL-8 R/B
3.07 km10-22 04:10 UTC
COSMOS 2170COSMOS 2201
4.61 km10-29 19:41 UTC
COSMOS 2167COSMOS 2170

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 2170 ⟷ SL-8 R/B: 3.18 km predicted close approach”, https://orbitalradar.com/conjunction/21784-7426 (accessed 2026-10-28).