Laura Pirovano, NorthStar Earth & Space; Yashica Khatri, NorthStar Earth & Space; Narendra Gollu, NorthStar Earth & Space; Matteo Budoni, NorthStar Earth & Space; Guillermo Escribano Blázquez, NorthStar Earth & Space
Keywords: Fragmentation event, Break-up, Cataloguing, IOD
Abstract:
On October 19, 2024, the Intelsat 33E geosynchronous communications satellite experienced an explosive failure and fragmented into multiple pieces of debris (Rainbow, 2024). The event was detected soon after occurrence, determining the number and orbits of the pieces in the debris field proved challenging. The specific cause of the breakup was not known, so there were no estimates of the nature of the fragmentation, the forces that may have been applied to the objects, or the resulting delta-V’s. Estimates ran from twenty fragments initially to as many as hundreds. The scenario to be worked on resembled that of a surveillance effort: new fragments were very briefly observed, falling into the so-called very-short arc (VSA) problem, and re-observation only happened after long gaps of time, if ever.
Data providers were able to supply NorthStar with the UCT IDs they associated with the break-up. NorthStar’s automated pipeline initiated an N-Gooding algorithm (Henderson, 2010) for each UCT ID to perform an initial orbit determination (IOD), which was then automatically updated with an orbit determination (OD) through the extended Kalman filter (EKF) on the full perturbation model once new observations became available. Due to the VSA nature of the tracklets, the team also ran manual IODs leveraging the full arc length of the tracklets, including the use of batch least squares (BLSQ) to exploit all available data and obtain reliable states for the fragments. In addition, an Adaptive Robust Kalman Filter (ARKF) was used to adapt the orbit more quickly to the incoming new observations.
Twice a day, NorthStar generated a list of all the catalogued debris in the form of two-line elements (TLEs), and identified any future close approaches with operative satellites due to the new debris (a COMBO assessment).
The event tested the brand-new IOD pipeline which had been deployed a few days before the break-up. This aided in the success of the UCT handling, otherwise impossible with manual intervention. It also uncovered criticalities in handling borderline too-short arcs (TSAs) with predefined parameters, which made the team intervention necessary to ensure a successful IOD and OD on the fragments. The event has shaped NorthStar roadmaps to improve our automated cataloguing efforts to be able to handle such events and keep an accurate catalogue to ensure a safe utilization of space.
Henderson, M. D. (2010). Modifications to the gooding algorithm for angles-only initial orbit determination. AAS/AIAA Space Flight Mechanics Meeting.
Rainbow, J. (2024). Intelsat 33E break-up. Retrieved from spacenews.com: https://spacenews.com/exoanalytic-observes-500-pieces-of-debris-from-intelsat-33e-breakup/
Date of Conference: September 16-19, 2025
Track: Space Debris