EU SST confirms re-entry of space object CZ-5B

The EU Space Surveillance and Tracking (EU SST) has monitored the re-entry of large space object CZ-5B (2022-085B), the core stage of the rocket that launched Wentian – the second module of the Chinese large modular space station – on 24 July 2022. The EU SST network of sensors observed the object closely, and its radars narrowed down its re-entry window to 30 July.

Latest update: 2022-07-30 21:50 UTC+2

Based on EU SST analysis and external information, EU SST confirms that object CZ-5B decayed on 2022-07-30 16:45 UTC ±15 minutes.

Re-entry window evolution of object CZ-5B as of 30 July 2022.

EU SST contributing sensors confirmed that the object was tumbling. The below figure shows the Velocity Time Intensity (VTI) of the object during the pass observed by the MFDR radar, with a tumbling speed of 3.3 seconds per revolution, which suggested a fairly fast rotation. Due to its inclination (41.47 degrees), the object could re-enter within the latitude band ±41.47 deg. These predictions however came with uncertainties as the object was uncontrolled, and a better estimation was only possible a few hours before the actual re-entry.

Velocity Time Intensity (VTI) of the object detected by MFDR radar during the pass, with a tumbling speed of 3.3 seconds per revolution.

Map of radars from the EU SST sensors network contributing to the event as of 30 July 2022

The below figure shows the ground track for the last estimated re-entry window 2022-07-30 17:24:11 UTC ±58 minutes.

Map of the whole ground track.
Green lines: ground track during the re-entry window. Red lines: part of ground track over EU Member States. Marker: centre of the predicted re-entry window.
Note: possible re-entry locations lie anywhere along the green lines. The re-entry point was considered to be at an altitude of 80 km.

Object CZ-5B had a mass ranging from 17 to 23 tonnes and a size of about 30 m, which made it one of the largest pieces of debris re-entering in the near past and therefore it deserved careful monitoring.

Note: this article will be updated with the latest information provided by EU SST’s Operations Centres.

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