## Session

Technical Session VIII: Frank J. Redd Student Scholarship Competition

## Abstract

A de-orbiting strategy for small satellites, in particular CubeSats, is proposed which exploits the effect of solar radiation pressure to increase the spacecraft orbit eccentricity so that the perigee falls below an altitude where atmospheric drag will cause the spacecraft orbit to naturally decay. This is achieved by fitting the spacecraft with an inflatable reflective balloon. Once this is fully deployed, the overall area-to-mass ratio of the spacecraft is increased; hence solar radiation pressure and aerodynamic drag have a greatly increased effect on the spacecraft orbit. An analytical model of the orbit evolution due to solar radiation pressure and the J2 effect as a Hamiltonian system shows the evolution of an initially circular orbit. The maximum reachable orbit eccentricity as a function of semi-major axis and area-to-mass ratio can be found and used to determine the size of balloon required for de-orbiting from circular orbits of different altitudes. A system design of the device is performed and the feasibility of the proposed de-orbiting strategy is assessed and compared to the use of conventional thrusters. The use of solar radiation pressure to increase the orbit eccentricity enables passive de-orbiting from significantly higher altitudes than conventional drag augmentation devices.

*Presentation Slides*

A Passive High Altitude Deorbiting Strategy

A de-orbiting strategy for small satellites, in particular CubeSats, is proposed which exploits the effect of solar radiation pressure to increase the spacecraft orbit eccentricity so that the perigee falls below an altitude where atmospheric drag will cause the spacecraft orbit to naturally decay. This is achieved by fitting the spacecraft with an inflatable reflective balloon. Once this is fully deployed, the overall area-to-mass ratio of the spacecraft is increased; hence solar radiation pressure and aerodynamic drag have a greatly increased effect on the spacecraft orbit. An analytical model of the orbit evolution due to solar radiation pressure and the J2 effect as a Hamiltonian system shows the evolution of an initially circular orbit. The maximum reachable orbit eccentricity as a function of semi-major axis and area-to-mass ratio can be found and used to determine the size of balloon required for de-orbiting from circular orbits of different altitudes. A system design of the device is performed and the feasibility of the proposed de-orbiting strategy is assessed and compared to the use of conventional thrusters. The use of solar radiation pressure to increase the orbit eccentricity enables passive de-orbiting from significantly higher altitudes than conventional drag augmentation devices.