## Abstract

A technique for earth escape using a solar sail is derived and numerically simulated. The sail is assumed to be initially placed in a geosynchronous transfer orbit (GTO). A sail force vector control algorithm is derived and implemented that continuously orients the sail in three-dimensions to maximize the component of sail force along the velocity vector at each point along the trajectory. This approach maximizes the instantaneous rate of increase of the total orbital energy. The equations of motion for the trajectory are expressed in modified equinoctial orbital elements, which are well-behaved as the trajectory goes from elliptic to hyperbolic during escape. This is a preliminary study in which a spherical gravity model for the earth is assumed. Atmospheric drag, shadowing effects of the earth, and lunar/solar gravitation are neglected. No sail angle, sail angle rate, or minimum perigee radius constraints are included. Numerical results confirm that escape does occur, with the escape time highly dependent on the sail acceleration magnitude and somewhat dependent on the initial orbit geometry.

Original language | English (US) |
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Pages (from-to) | 507-519 |

Number of pages | 13 |

Journal | Advances in the Astronautical Sciences |

Volume | 103 |

Issue number | PART 1 |

State | Published - Dec 1 2000 |

## ASJC Scopus subject areas

- Aerospace Engineering
- Space and Planetary Science