Home›Maneuver Tracker›Close Approaches›SJ-29B ⟷ ESIAFI 1 (COMSTAR 4)
HighCross-border
On permanent record
Final forecastFinal forecast, made 6 min before the pass.
Closest approach6 Nov 202600:01 UTC
Drift speed621 m/s2,235 km/h, seen from ESIAFI 1 (COMSTAR 4)
Altitude35,789 kmnear the geostationary belt
Last confirmed5 Nov23:55 UTC · final forecast

CN SJ-29B and US ESIAFI 1 (COMSTAR 4) were predicted to reach a closest approach of 4.33 km at 2026-11-06 00:01 UTC, drifting past at about 621 m/s (2,235 km/h) as seen from ESIAFI 1 (COMSTAR 4). Final forecast, made 6 min before the pass. This is a cross-border encounter between objects of different nations, the kind of event closely watched for space-security implications. 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
SJ-29BPayload
NORAD 67403
CountryPRC
Launched2025-12-30
COSPAR2025-315C
Maneuver capableUnknown
NORAD 12309
CountryUS
Launched1981-02-21
COSPAR1981-018A
Maneuver capableUnknown

Where This Happens

Altitude context
GEO BELT 35,786 KMTHIS PASS · 35,789 KMLEOMEOGEO

This pass happens near the geostationary belt, where satellites hold fixed longitude slots and relative speeds are low. Close approaches here are usually slow drifts rather than crossing passes. About GEO →

History Between This Pair

1 predicted pass under 10 km
Pair history · SJ-29B ⟷ ESIAFI 1 (COMSTAR 4)
2026-11-06 00:014.33 km Final forecast0.62 km/s35,789 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 Nothing is overwritten: a withdrawn forecast keeps its figure, with the newer check beside it, and the best estimate after the pass is a row of its own.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
5 Nov 09:11 UTC4.33 km Forecast6 Nov 00:01 UTC4 Nov 21:47 UTCRe-check
5 Nov 00:11 UTC4.44 km Forecast6 Nov 00:01 UTC3 Nov 23:32 UTCScreen

These Objects Elsewhere

Other screened approaches · 7 days
7.27 km11-04 00:09 UTC
SJ-29AESIAFI 1 (COMSTAR 4)

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 →

✓ Permanent record. This encounter met the notability thresholds and keeps an archived page after the pass.