10. The Algorithm of the Two-Impulse Time-Fixed Noncoplanar Rendezvous with Drag and Oblateness Effects

The algorithm that generates the exact solution of the two-impulse noncoplanar rendezvous in general elliptic orbit is presented in this chapter. The motion of the maneuvering spacecraft is referred to a rotating reference frame attached to the passive spacecraft, and dragging and precessing at the same rate as that spacecraft. An iterative scheme is devised to find the magnitude and orientation of the initiating impulse that brings the active spacecraft to a desired target point in the vicinity of the passive spacecraft in a given time. When the rendezvous point is in the vicinity of the passive spacecraft and not at the passive vehicle location itself, the linear distance between the two vehicles will exhibit variations along their post-rendezvous common orbit which can be of the order of kilometers for highly eccentric orbits. These natural oscillations can be minimized by targeting the active vehicle to the immediate proximity of the passive spacecraft, and be totally eliminated by targeting to the passive vehicle location itself.