US4837699A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for controlling the spin axis attitude of a spinning spacecraft
Assignee: The AT&T MVPD Group LLC
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Filing: 1988-07-05
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Granted: 1989-06-06
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Expires: 2008-07-05
Abstract
Abstract A system located on board a geosynchronous satellite for detecting spin axis precession and developing thruster control signals for restoring the spin axis to the desired attitude. Fuel economy is enhanced by performing the major attitude correction at a time when the fuel expended contributes to that required for orbit inclination control.
Inventors
- 👤 John W. Smay
- 👤 William F. Hummel, Jr.
- 👤 Carl L. Chen
- 👤 Loren I. Slafer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 01:01
CPC Classifications
B; B64; B64G; B64G1/00; B64G1/22; B64G1/24; B64G1/26; B64G1/244
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
125 words
A method for controlling the spin axis attitude and orbit inclination of a spinning spacecraft in a geosynchronous orbit comprising the steps of: sensing the direction of the earth from the spacecraft to detect deviations of the spacecraft spin plane from coincidence with the spacecraft orbital plane and developing signals in accordance with the detected deviation; generating signals for controlling the activation of spacecraft thrusters in response to said detected deviation signals; and selectively applying the thruster control signals to activate a selected thruster when the spacecraft is in the vicinity of a descending orbit node and at a predetermined point on the rotation of the spacecraft to develop an element of orbit plane adjustment and a correction of the deviation of the spin axis.
Claim 2
Independent Claim
125 words
A method for controlling the spin axis attitude and orbit inclination of a spinning spacecraft in a geosynchronous orbit comprising the steps of: sensing the direction of the earth from the spacecraft to detect deviations of the spacecraft spin plane from coincidence with the spacecraft orbital plane and developing signals in accordance with the detected deviation; generating signals for controlling the activation of spacecraft thrusters in response to said detected deviation signals; and selectively applying the thruster control signals to activate a selected thruster when the spacecraft is in the vicinity of a descending orbit node and at a predetermined point on the rotation of the spacecraft to develop an element of orbit plane adjustment and a correction of the deviation of the spin axis.
Claim 3
Dependent Claim
71 words
The method of claim 1 and further including the step of performing a series of minor spin axis attitude error corrections symmetrically positioned about the descending orbit node to maintain the spin axis attitude error within a specified range and wherein the thruster activation in the vicinity of the descending orbit node is controlled to develop a major spin axis attitude correction in response to substantial spin axis attitude error measurements.
Claim 4
Dependent Claim
29 words
The method of claim 1 wherein the step of selectively applying the thruster control signals is performed a predetermined number of times on opposite sides of the orbit node.
Claim 5
Independent Claim
140 words
A method for controlling the spin axis attitude and orbit plane inclination of a spinning spacecraft in a geosynchrous orbit comprising the steps of: sensing the direction of the earth from the spacecraft to detect deviations of the spacecraft spin plane from coincidence with the spacecraft orbital plane and developing signals in accordance with the detected deviation; generating signals for controlling the activation of spacecraft thrusters in response to the detected deviation signals; performing a plurality of minor spin axis attitude error corrections symmetrically positioned about the descending orbit node in response to the thruster control signals to maintain the spin axis attitude error within a specified threshold range; and applying the thruster control signals in the vicinity of the descending orbit node to develop a major spin axis attitude correction in response to substantial spin axis attitude error measurements.
Claim 6
Independent Claim
140 words
A method for controlling the spin axis attitude and orbit plane inclination of a spinning spacecraft in a geosynchrous orbit comprising the steps of: sensing the direction of the earth from the spacecraft to detect deviations of the spacecraft spin plane from coincidence with the spacecraft orbital plane and developing signals in accordance with the detected deviation; generating signals for controlling the activation of spacecraft thrusters in response to the detected deviation signals; performing a plurality of minor spin axis attitude error corrections symmetrically positioned about the descending orbit node in response to the thruster control signals to maintain the spin axis attitude error within a specified threshold range; and applying the thruster control signals in the vicinity of the descending orbit node to develop a major spin axis attitude correction in response to substantial spin axis attitude error measurements.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-06-05 | 1992-12-05 | 1993-06-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-06-05 | 1996-12-05 | 1997-06-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-06-05 | 2000-12-05 | 2001-06-06 | $7700.00 | Window Closed / Lapsed |