Safing mode for high momentum states in body stabilized spacecraft
US6550721B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 9, 2001 |
| Grant date | Apr 22, 2003 |
| Priority date | — |
| Expiry date | Mar 9, 2021 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB64G1/247
- WIPO fieldTransport
- WIPO sectorMechanical engineering
Abstract
A spacecraft with a reaction wheel system can be autonomously safed by setting the solar wings to continuous tracking, determining a slew rate vector based on the total angular momentum, and slewing the spacecraft using the slew rate vector until commanded to stop autonomous safing. When the total angular momentum of the spacecraft to large to be handled by rotisserie, then the spacecraft is reoriented to align a suitable rotation vector with the system momentum. In a typical application, the spacecraft has a reaction wheel assembly with four wheels arranged to form a right regular pyramid. Two reaction wheels on opposite edges of the pyramid form a first pair and the two remaining reaction wheels forming a second pair. The slew axis of rotation is found by determining as a selected pair the first pair if either reaction wheel in the second pair is inoperative, otherwise determining as the selected pair the second pair and determining as the slew axis of rotation the normalized projection of the axes of rotation of the selected pair onto the base. The slew direction is determined by the sign of the total angular momentum component along the slew axis of rotation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.