Home›Maneuver Tracker›Close Approaches›TJS-27A ⟷ DELTA 1 DEB
HighCross-border
On permanent record
Live forecastConfirmed by the latest screening, 21 Oct 13:51 UTC.
Closest approach22 Oct 202604:28 UTC
Relative speed13.87 km/sat the closest approach
Altitude1,156 kmlow Earth orbit
Separation now—live

CN TJS-27A and US DELTA 1 DEB are predicted to reach a closest approach of 4.16 km at 2026-10-22 04:28 UTC, at a relative speed of 13.87 km/s. Confirmed by the latest screening, 21 Oct 13:51 UTC. 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 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
TJS-27APayload
NORAD 100174
CountryPRC
Launched2026-07-30
COSPAR2026-173A
Maneuver capableUnknown
NORAD 21281
CountryUS
Launched1975-06-12
COSPAR1975-052S
Maneuver capableNo
Uncontrolled debris fragment tracked by the public catalogue. About space debris →

Where This Happens

Altitude context
DEBRIS BELT 700–1000 KM2006001,0001,5002,000 kmTHIS PASS · 1156 KMISS 420Starlink 550

At 1156 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 · TJS-27A ⟷ DELTA 1 DEB
2026-10-22 04:284.16 km Live forecast13.87 km/s1,156 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 Nothing is overwritten: a withdrawn forecast keeps its figure, with the newer check beside it, and the best estimate after the pass is a row of its own.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
21 Oct 13:30 UTC4.16 km Forecast22 Oct 04:28 UTC21 Oct 06:30 UTCRe-check
21 Oct 12:26 UTC4.18 km Forecast22 Oct 04:28 UTC21 Oct 02:08 UTCScreen

These Objects Elsewhere

Other screened approaches · 7 days
3.75 km10-21 03:04 UTC
TJS-27ACOSMOS 2499 DEB
4.71 km10-20 23:14 UTC
TJS-27AHULIANWANG DIGUI-109
4.96 km10-22 06:34 UTC
TJS-27AHULIANWANG DIGUI-90

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 — “TJS-27A ⟷ DELTA 1 DEB: 4.16 km predicted close approach”, https://orbitalradar.com/conjunction/100174-21281 (accessed 2026-10-21).
✓ Permanent record. This encounter met the notability thresholds and keeps an archived page after the pass.