TETHER-ASSISTED SPACE DEBRIS REMOVAL WITH AN AEROBRAKE: PRELIMINARY ESTIMATION OF MISSION PARAMETERS

Abstract

This paper investigates the application of an aerobrake in a tether system for space debris removal and provides a preliminary assessment of the key mission parameters. Tether system stability is analyzed using a one degree of freedom mathematical model. Corresponding drag requirements are determined. The results indicate that systems with longer tethers at higher altitudes would require higher drag coefficients to maintain stability. The relative motion of the target with respect to the tug following separation is examined using the Clohessy-Wiltshire equations. Based on the resulting trajectories, the relationship between maximum tether elongation and the target's initial velocity is established. The orbital motion of the tether system during the descent phase is studied through numerical simulations. The descent duration is evaluated for three tether system configurations with different aerodynamic coefficients at three initial altitudes. A ±15%  variation in atmospheric density is applied to account for atmospheric density uncertainty. The results demonstrate that increasing the drag coefficient through an increase in surface area significantly reduces the descent duration across all investigated cases, demonstrating the potential of aerobraking to improve the de-orbiting performance of tether systems.