Home›Maneuver Tracker›Close Approaches›DMSP 5D-3 F16 (USA 172) ⟷ THOR BURNER 2 R/B
HighProximity
Final forecastFinal forecast, made minutes before the pass.
Closest approach8 Nov 202610:56 UTC
Relative speed14.67 km/sat the closest approach
Altitude846 kmlow Earth orbit
Last confirmed8 Nov10:55 UTC · final forecast

US DMSP 5D-3 F16 (USA 172) and US THOR BURNER 2 R/B were predicted to reach a closest approach of 3.32 km at 2026-11-08 10:56 UTC, at a relative speed of 14.67 km/s. Final forecast, made minutes 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
NORAD 28054
CountryUS
Launched2003-10-18
COSPAR2003-048A
Maneuver capableUnknown
NORAD 7817
CountryUS
Launched1975-05-24
COSPAR1975-043B
Maneuver capableNo
Spent rocket stage: uncontrolled, tracked by the public catalogue.

Where This Happens

Altitude context
DEBRIS BELT 700–1000 KM2006001,0001,5002,000 kmTHIS PASS · 846 KMISS 420Starlink 550

At 846 km this pass sits inside the most congested band in low Earth orbit, home to the debris left by the 2007 ASAT test and the 2009 collision. 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 · DMSP 5D-3 F16 (USA 172) ⟷ THOR BURNER 2 R/B
2026-11-08 10:563.32 km Final forecast14.67 km/s846 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 Nothing is overwritten: a withdrawn forecast keeps its figure, with the newer check beside it, and the best estimate after the pass is a row of its own.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
8 Nov 10:37 UTC3.32 km Forecast8 Nov 10:56 UTC7 Nov 23:32 UTCRe-check
8 Nov 10:28 UTC9.29 km Forecast8 Nov 10:56 UTC7 Nov 23:32 UTCScreen

These Objects Elsewhere

Other screened approaches · 7 days
3.44 km11-11 20:27 UTC
DMSP 5D-3 F16 (USA 172)COSMOS 1275 DEB
4.44 km11-04 22:26 UTC
DMSP 5D-3 F16 (USA 172)FENGYUN 1C DEB
4.62 km11-05 06:05 UTC
DMSP 5D-3 F16 (USA 172)FENGYUN 1C 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 →