Abstract: A space telescope having a primary mirror for focusing and reflecting electromagnetic radiation, multiple secondary mirrors and, optionally, multiple tertiary mirrors, for receiving the focused and reflected electromagnetic radiation from the primary mirror and reflecting the electromagnetic radiation, and multiple focal plane arrays for receiving the focused and reflected electromagnetic radiation from the secondary mirrors or tertiary mirrors. The use of a multiple secondary mirrors and multiple focal plane arrays allows the telescope to observe multiple fields of regard simultaneously in selected celestial regions or on an orbited celestial body, such as the Earth.

Abstract: A structureless space telescope is disclosed. The structureless primary mirror includes a plurality of mirror elements for focusing and reflecting electromagnetic radiation, and the telescope further includes at least one secondary mirror and possibly a tertiary mirror for receiving the focused and reflected electromagnetic radiation from the structureless primary mirror and reflecting the electromagnetic radiation, and at least one focal plane array for receiving the focused and reflected electromagnetic radiation from the secondary mirror or tertiary mirror, wherein the plurality of mirror elements, the secondary mirror and the focal plane array are coordinated and controlled without a physical structure connecting the plurality of mirror elements.

Abstract: A method for increasing the payload that can be delivered by a given launch vehicle to a selected target in an interplanetary space mission, without increasing the transfer time to reach the target. In accordance with the disclosed method, a conventional multi-stage launch vehicle is used to accelerate a payload spacecraft to near earth's escape velocity. Then the spacecraft is separated from the upper stage of the launch vehicle and is further accelerated by applying a velocity impulse with an onboard propulsion system into a transfer trajectory that takes the spacecraft to the target planet. Because the upper stage of the launch vehicle is not accelerated into the same transfer trajectory, a larger payload mass can be delivered to the target planet without increasing the transfer time. Alternatively, the transfer time can be reduced without decreasing the payload mass or changing the launch vehicle configuration.

Abstract: A technique for maintaining a satellite in an assigned orbit without control or intervention from the ground. Autonomously obtained navigational data provide a measurement of the actual orbit in which the satellite is traveling. So long as the measured orbit conforms to a desired orbit to within a preselected tolerance, periodic corrections of equal magnitude are made to the satellite's velocity, based on a prediction of the effect of atmospheric drag on the orbit. Measurement of the orbit is made by observation of the time that the satellite passes a reference point in the orbit, such as by crossing the ascending node. If the measured orbit departs from the desired orbit by more than the preselected tolerance, a velocity correction of a magnitude different from the one based on prediction is applied to the satellite. For a decaying orbit, the magnitude of the velocity correction is increased above the correction value based on prediction.

Abstract: A technique for maintaining a satellite in an assigned orbit without control or intervention from the ground. Autonomously obtained navigational data provide a measurement of the actual orbit in which the satellite is traveling. So long as the measured orbit conforms to a desired orbit to within a preselected tolerance, periodic corrections of equal magnitude are made to the satellite's velocity, based on a prediction of the effect of atmospheric drag on the orbit. Measurement of the orbit is made by observation of the time that the satellite passes a reference point in the orbit, such as by crossing the ascending node. If the measured orbit departs from the desired orbit by more than the preselected tolerance, a velocity correction of a magnitude different from the one based on prediction is applied to the satellite. For a decaying orbit, the magnitude of the velocity correction is increased above the correction value based on prediction.

Abstract: A method and corresponding apparatus for providing spacecraft attitude, position and orbit data without the need for externally supplied data. Using onboard observations of the earth, sun and moon, the system determines spacecraft attitude, instantaneous position, and the orbit based on multiple position estimates. Position and orbit data are derived by multiple deterministic solutions, including some that employ star sensors and gyros, and the multiple solutions are accumulated in a Kalman filter, to provide continuous estimates of position and orbit for use when the sun or moon is not visible. The best estimate of position is selected from the multiple deterministic solutions and the Kalman filter solution, and can be used to control the spacecraft in various ways, without having to rely on ground-based equipment or other spacecraft for the determination of position and orbit.

Abstract: A controller for effecting transistion of a spacecraft from one orbit to another without reliance on ground-based control stations. The controller as disclosed includes at least two conical earth sensors which are normally employed for detection and control of spacecraft orientation, to provide signals indicative of altitude. When the spacecraft altitude is below a selected threshold, the controller activates a rocket motor to raise the high point of the orbit. A second comparison, with a low threshold value of sensed angular diameter of the earth, indicates when a desired orbital altitude is first reached. The controller, and a related method for its use, enable a spacecraft to effect a transistion between orbits without complex on-board computers and without significant control from the ground.