Aeronautics and astronautics – Spacecraft – Attitude control
Reexamination Certificate
1999-06-03
2001-07-17
Barefoot, Galen L. (Department: 3644)
Aeronautics and astronautics
Spacecraft
Attitude control
C168S039001
Reexamination Certificate
active
06260806
ABSTRACT:
TECHNICAL FIELD
The present invention relates to attitude stabilization of a spacecraft during an eclipse. More specifically, the present invention relates to attitude stabilization of a spacecraft during an eclipse through the use of a momentum bias.
BACKGROUND ART
Currently, all spacecraft require constant power from an electrical power source to support the operation of control actuators, to power the payload, to maintain thermal stability, and to control a host of other functions. An example of such a spacecraft, employs a reaction wheel system that is configured in a pyramid for attitude control while utilizing photovoltaic arrays for electrical power. An inherent limitation of this system and others that rely on electrical power is that these systems cannot be used during a solar eclipse without the use of an auxiliary power source.
Accordingly, all current spacecraft require some source of stored electrical power or auxiliary power to maintain their subsystem functionalities during an eclipse in addition to requiring an electric power source to support the operation of normal spacecraft functions. These stored or auxiliary power sources include, for example, batteries or other similar devices. Currently, if a spacecraft does not utilize some source of stored or auxiliary power to control its attitude, the spacecraft will lose power upon entering an eclipse, potentially causing the spacecraft attitude to deteriorate to a state causing permanent damage to vital spacecraft systems. Moreover, these spacecrafts that carry auxiliary power sources, such as batteries, carry additional weight which can decrease the payload capacity and also increase the cost of manufacturing and operation of the spacecraft. Therefore, a spacecraft that can maintain stability through an eclipse without the need for auxiliary power would be desirable.
While the use of a momentum bias to induce passive attitude stabilization in a spacecraft is well known, there are, however, no known methods or apparatus that utilize a momentum bias for eclipse storage on a spacecraft without dependence on auxiliary power. Moreover, there are no known methods or apparatus that utilize a momentum bias for eclipse storage on a spacecraft that is designed to be actively controlled in three axis during periods of sunlight.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a spacecraft that provides passive attitude control of the spacecraft during a solar eclipse through the use of an angular momentum bias.
It is another object of the present invention to provide attitude control of a spacecraft during an eclipse without the need for a stored or auxiliary power source.
It is a further object of the present invention to provide a spacecraft that eliminates the need for an auxiliary power source to maintain subsystem functionalities during a solar eclipse by providing for thermal protection of the subsystem functionalities so that they will operate following the solar eclipse.
In accordance with these and other objects of the present invention, a method for controlling the attitude of a spacecraft without dependence on auxiliary power during a solar eclipse is provided. In anticipation of the solar eclipse, the spacecraft is configured so that it will receive solar power prior to and following the solar eclipse. The spacecraft is then spun to a desired rate of rotation and a desired angular momentum about a stable or neutrally stable body axis (the axes of maximum or minimum moment of inertia, respectively). The spacecraft is spun so that it maintains the desired angular momentum throughout the eclipse and provides passive stabilization of the attitude. After the solar eclipse has passed, the spacecraft power is restored and the spacecraft attitude is known. All spacecraft units are then powered up and thereafter, normal on-station attitude is re-established and normal spacecraft operations are established.
These and other features and advantages of the present invention will become apparent from the following description of the invention, when viewed in accordance with the accompanying drawings and appended claims.
REFERENCES:
patent: 3471105 (1969-10-01), Yarber et al.
patent: 3995801 (1976-12-01), Bond
patent: 4078748 (1978-03-01), Sen
patent: 4691882 (1987-09-01), Young
patent: 4725024 (1988-02-01), Vorlicek
patent: 4735382 (1988-04-01), Pinson
patent: 5337981 (1994-08-01), Bender
patent: 5890679 (1999-04-01), Chethik
S. Rangarajan, “Novel Experiences with Insat-1B Operations”, Spaceflight Dynamics 1993, vol. 84, Part II, Advances in the Astronomical Sciences.
Olsen Christopher D.
Salvatore Jeremiah O.
Wallace Troy D.
Williams Paul D.
Barefoot Galen L.
Gudmestad T.
Hughes Electronics Corporation
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