On the morning of 12 November 2022, a Chang Zheng 6A rocket body disintegrated in Low Earth Orbit (LEO), contributing to space debris: the population of defunct artificially-created objects in space. This population includes old satellites and spent spacecraft components, as well as the fragments from their disintegration and collisions. The European Space Agency reports that 17985 objects are orbiting in LEO, with a particularly high-risk concentration at 850 km mean altitude and 70–80 degrees in inclination. Characterising fragment generation and the debris population is directly relevant to space operators, affecting both military and civilian space sectors and relating directly to economic and national security. The monitoring of uncontrolled or deliberate proliferation of space debris is a critical aspect of space situational awareness.

A Chang Zheng “Long March” 6A rocket (CZ-6A) was launched at 22:52 UTC on 11 November 2022 from Taiyuan, China. It deployed the Yunhai-3 satellite to a sun-synchronous orbit. However, on 13 November, the United States 18th Space Defence Squadron reported a breakup of the CZ-6A rocket body (NORAD number #54236, 2022-151B). As it was a large fragmentation and had been noted sufficiently early, rapid observational responses could be made by multiple actors. It would allow independent data to be obtained before the debris had dispersed (which would have made attribution uncertain) and confirm the nature of the breakup.

The instrument used was the EISCAT UHF incoherent scatter radar, located at Ramfjordmoen, Norway (Lat=69.586 deg N, Long=19.227 deg E), as it is suitable for for detecting small-size fragments. The measurements were carried out using a “beampark” observation: holding the antenna at a fixed position and letting the debris pass through the radar beam.

To predict the required beam direction and time, forward propagation of the potential debris cloud was made, based on the CZ-6A rocket body’s two-line element (TLE) parameters but with a uniformly distributed mean anomaly. Data were cross-checked using different software packages: SORTS, AstroPy and PyEphem. The UHF radar was fixed at Az=90, El=75 degrees and the observation ran from 12:52 to 16:45 UT on 16 November 2022. During the observation a total of 273 events were registered.

The relatively-low number of fragments, combined with the low dispersal of them in altitude, is in agreement with a breakup of the CZ-6A rocket body caused by self fragmentation. What can be ruled out is a collision with a large existing object, or an ASAT missile strike; both of these scenarios result in a larger number of fragments and a larger dispersal in altitude.

With the rising number of LEO satellites, future classification and analysis of incidents will become increasingly important. Accident investigation will help us identify causes and establish practices and policies to mitigate further catastrophes. This is important for modelling future events and predicting the ongoing deterioration of the LEO space environment due to space debris.