IRIDIUM 33

About This Satellite

Iridium 33 was an active commercial communications satellite when it collided with the derelict Cosmos 2251 on February 10, 2009. NASA's technical analysis describes the event as the first known unintentional hypervelocity collision between intact satellites. This is a historical mission record, not a listing of a functioning Iridium communications relay.

Why the collision speed was 11.6 kilometres per second

The analysis places the collision near 790 km altitude over Siberia, at a relative speed of 11.6 km/s. Relative speed describes how quickly the two objects approached each other along their different trajectories. It is not the speed that should be assigned to Iridium 33 alone in a normal orbital snapshot.

A breakup produced many trajectories, not one replacement orbit

The researchers examined debris size, mass, area-to-mass ratio, and velocity distributions. A single original satellite identifier cannot stand for all those fragments. Any retained elements on this page refer only to the associated catalog record, not to a restored spacecraft or a complete map of its debris cloud.

Mission reference: NASA NTRS: Analysis and Consequences of the Iridium 33-Cosmos 2251 Collision. Editorial review: 2026-09-14.

A predicted miss distance was not a guarantee of safety

NASA's account of conjunction assessment recounts a predicted separation before the Iridium accident, followed by loss of contact and radar detection of debris. It illustrates why nominal trajectories and their uncertainties must be considered together. This catalog's ground tracks lack the operational covariance analysis and decision process used for collision assessment; two lines appearing apart on a map cannot certify that an encounter is safe.

Reference: NASA: Iridium collision as a lesson in conjunction prediction and uncertainty.

One fragment affected ISS operations six years later

NASA reports that Iridium 33 fragment 34356 prompted an ISS avoidance maneuver on July 26, 2015, using a visiting Progress vehicle. Its higher atmospheric drag caused the concern to emerge less than eight hours before the predicted encounter. Additional tracking later reduced the estimated risk, but the burn continued once attitude control was underway. This dated example shows the long operational consequences of a breakup, not the present position or hazard level of that fragment.

Reference: NASA Safety and Mission Assurance: Iridium 33 fragment 34356 and the July 2015 ISS maneuver.

Reading this orbital snapshot

Based on TLE epoch: 2026-09-05. Estimated altitude ranges from 767 km at perigee to 782 km at apogee, a difference of 14 km. The orbital period is about 100.3 minutes. Eccentricity 0.00099 indicates a nearly circular path. In a two-body approximation, perigee speed is 1.00 times apogee speed. These are mean-element estimates, not instantaneous measurements. Distance per orbit uses an ellipse approximation.

Saved build snapshot. If a valid TLE is retrieved, this explanation and the orbit panel update together. Otherwise this dated snapshot is retained.

Ground track is not sensor coverage

An inclination of 86.39 degrees implies approximate geocentric ground-track limits of 86.4 degrees north and south. This is a prograde orbit, moving in the same general direction as Earth rotation. The plotted line marks the point beneath the object. It does not represent camera coverage, radio reception, or a guaranteed visible pass.

Accuracy and missing information

The introductory record describes the build snapshot. The orbital snapshot explanation and orbit panel share any successfully retrieved TLE; check the displayed epoch. Reentered objects retain historical data only. Mission history is not rewritten by TLE updates. TLE/SGP4 positions are predictions and can change after maneuvers or updated observations. The 14-day stale-data cutoff is a display safeguard, not an accuracy guarantee. Local passes are geometric predictions, not a visibility forecast. No verified operator or mission status means unknown, not active. Do not use this catalog for collision avoidance or operational flight decisions.

Catalog sources: CelesTrak SATCAT: NORAD 24946 · GCAT: S24946 (source update 2026 Sep 4 2345:57). Supplementary metadata: SatNOGS DB, retrieved 2026-09-05T12:57:25.375Z. Page assembled 2026-09-15. GCAT phase codes describe trajectory phases, not mission health.

Learn more: TLE data · Perigee and apogee · Ground tracks · JOT (Jewawud Live Orbital Map)

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