Tae Lim, United States Naval Academy; Francis Chun, U.S. Air Force Academy; Benjamin Roth, U.S. Air Force Academy; David Strong, Strong EO Imaging, Inc.; Timothy Giblin, i2 Strategic Services LLC
Keywords: Rocket body rotational motion characterization, photometric observation, Falcon Telescope Network, space debris removal
Abstract:
To ensure safe operating environment, mitigation and removal strategies and technologies for space debris are in development. Of particular interest are the rocket bodies (R/Bs) left in orbit after launching satellites as they pose significant potential threats to space assets due to their lack of maneuvering capabilities to avoid collision. To remove them safely, debris removal technology requires knowledge of their rotational motion profiles such as tumble rates, spin stability, and attitude. The Center for Space Situational Awareness Research in the Department of Physics and Meteorology at the U.S. Air Force Academy has been conducting research in space object characterization using non-imaging photometric observation data. A network of small aperture telescopes located around the globe, called the Falcon Telescope Network (FTN) was developed to conduct observation of various resident space objects in low earth orbits (LEOs) as well as geosynchronous earth orbits. The objective of this research is to develop modeling and simulation capabilities for R/Bs in LEO to characterize and validate their rotational motion profiles using the correlation of the model predictions against the observed photometric data available from the FTN, known as light curves. This modeling process incorporates four major contributors to the photometric measurements: rotational motion, R/B geometry, optical properties and reflections, and R/B observation geometry. To characterize rotational motion, which is the primary objective of this paper, R/B was treated as an axisymmetric cylindrical rigid body. This approach provides a systematic means to explore attitude dynamics and resulting motion of various R/Bs. It allows correlation of inertia properties with rotation behavior and provides a single framework that can explore minor axis spin, major axis spin, nutation/coning motion. Initial investigation indicates that the length over diameter (L/D) ratio of R/B has a significant impact on rotation behavior, thus resulting photometric light curves. R/Bs with larger L/D ratio tend to have a longer oscillation period in the light curves. For the same object, oscillation frequencies observed in the light curves can change by a factor of two solely by changing the orientation of sun vector with respect to its angular momentum vector, which was observed in the measured light curves. To support the effort, a parametric study model was developed to include the four components mentioned above.
Date of Conference: September 16-19, 2025
Track: Satellite Characterization