Abstract: A spacecraft control system and method for determining the necessary delta-V and timing for impulsive maneuvers to change the plane of an orbit or the size of the orbit of a secondary spacecraft that is in an orbit around a primary spacecraft. The system and method uses an apocentral coordinate system for the relative orbital motion and geometric relative orbital elements to determine the required impulsive velocity change and time to maneuver, for relative orbital changes in which only one of slant or colatitude of the sinilaterating node changes.

Abstract: A spacecraft control system and method for determining the necessary delta-V and timing for impulsive maneuvers to change the plane of an orbit or the size of the orbit of a secondary spacecraft that is in an orbit around a primary spacecraft. The system and method uses an apocentral coordinate system for the relative orbital motion and geometric relative orbital elements to determine the required impulsive velocity change and time to maneuver, for relative orbital changes in which only one of slant or colatitude of the sinilaterating node changes.

Abstract: A radio-frequency interferometry method for determining parameters of motion of a moving object from phase difference information from an antenna baseline formed of two antennas. At each of a plurality of observation events, compute a posterior probability density function from the phase differences from the baseline, separate the modes with a threshold value of probability density, and compute a probability of each mode. For each possible sequence of modes, determine a mode sequence probability as the product of the probabilities of each mode in that sequence, estimate a ?2 goodness of fit function based on an assumed type of motion. Determine the net probability of each possible sequence of modes as the product of a relative probability derived from the ?2 and the mode sequence probability. Alternately, two or more parallel or colinear baselines are used, and the posterior PDF is a combined PDF over each of the baselines.

Abstract: A technique to assist guidance techniques for a free-flying inspection vehicle for inspecting a host satellite. The method solves analytically in closed form for relative motion about a circular primary for solutions that are non-drifting, i.e., the orbital periods of the two vehicles are equal, computes the impulsive maneuvers in the primary radial and cross-track directions, and parameterizes these maneuvers and obtain solutions that satisfy constraints, for example collision avoidance or direction of coverage, or optimize quantities, such as time or fuel usage. Apocentral coordinates and a set of four relative orbital parameters are used. The method separates the change in relative velocity (maneuvers) into radial and crosstrack components and uses a waypoint technique to plan the maneuvers.

Abstract: A technique to assist guidance techniques for a free-flying inspection vehicle for inspecting a host satellite. The method solves analytically in closed form for relative motion about a circular primary for solutions that are non-drifting, i.e., the orbital periods of the two vehicles are equal, computes the impulsive maneuvers in the primary radial and cross-track directions, and parameterizes these maneuvers and obtain solutions that satisfy constraints, for example collision avoidance or direction of coverage, or optimize quantities, such as time or fuel usage. Apocentral coordinates and a set of four relative orbital parameters are used. The method separates the change in relative velocity (maneuvers) into radial and crosstrack components and uses a waypoint technique to plan the maneuvers.