Minimum-Time, Constant-Thrust Orbit Transfers with Noncircular Boundary Conditions

摘要

It has been shown previously that the accumulated velocity change of a spacecraft under continuous thrust is nearly constant over a wide range of thrust magnitudes for multi-revolution, time-optimal orbit transfers, approximately equal to the difference in initial and final circular velocities. This -same behavior exists for multi-revolution transfers between non-circular orbits, but the value of the accumulated velocity change must be determined numerically. For continuous-thrust transfers of less than one revolution, the approximate initial Lagrange costates and final flight times for minimum-time orbit transfers have been shown to reduce to simple algebraic expressions which may be used to initialize continuation methods. If the smaller of either the initial or final orbits is noncircular, chaotic behavior may be observed using continuation methods. This paper examines chaotic discontinuities and local minima in the continuation method and offers techniques to help automate parameter searches for minimum-time, continuous-thrust orbit transfers.