초록 ▼

Spacecraft thruster systems are provided that can realize station changing, station keeping and momentum dumping in spacecraft while minimizing loss of spacecraft service time. The systems are formed with pairs of E and W thrusters, NE and SE thrusters and NW and SW thrusters whose thrust directions

Spacecraft thruster systems are provided that can realize station changing, station keeping and momentum dumping in spacecraft while minimizing loss of spacecraft service time. The systems are formed with pairs of E and W thrusters, NE and SE thrusters and NW and SW thrusters whose thrust directions are each defined by respective polar angles .phi. and slew angles .alpha.. The E and W thrusters are especially suited for rapid station changing while the remaining thrusters generate normal, tangential and radial thrust components required for station keeping. Because all thrusters are directed through the spacecraft's center of mass during station changing and station keeping firings, the spacecraft's attitude is not disturbed and loss of service time is avoided. The thrusters are preferably gimbaled so that they can track spatial changes of the spacecraft's center of mass or, for momentum dumping, be offset from that center of mass. The normal tangential and radial thrust components of the thruster systems are arranged so that station changing, station keeping and momentum dumping are still realized after the failure of any thruster pair.

대표청구항 ▼

1. A thruster system that facilitates station changing, station keeping and momentum dumping for a spacecraft when it is in an orbital plane with its yaw axis directed substantially at the earth, its roll axis directed substantially along the spacecraft's velocity vector and its pitch axis directed

1. A thruster system that facilitates station changing, station keeping and momentum dumping for a spacecraft when it is in an orbital plane with its yaw axis directed substantially at the earth, its roll axis directed substantially along the spacecraft's velocity vector and its pitch axis directed substantially normal to said orbital plane, the system comprising:a northeast (NE) thruster that is tilted southward from said pitch axis by a NE polar angle that is less than 80.degree. and rotated eastward from said yaw axis by a NE slew angle that is less than 80.degree.; a southeast (SE) thruster that is tilted northward from said pitch axis by a SE polar angle that is less,than 80.degree. and rotated eastward from said yaw axis by a SE slew angle that is less than 80.degree.; an east (E) thruster that is tilted southward from said pitch axis by an E polar angle that is sufficient to position said E thruster between said NE and SE thrusters and rotated eastward from said yaw axis by an E slew angle that is less than 80.degree.; a northwest (NW) thruster that is tilted southward from said pitch axis by a NW polar angle that is less than 80.degree. and rotated westward from said yaw axis by a NW slew angle that is less than 80.degree.; a southwest (SW) thruster that is tilted northward from said pitch axis by a SW polar angle that is less than 80.degree. and rotated westward from said yaw axis by a SW slew angle that is less than 80.degree.; and a west (W) thruster that is tilted southward from said pitch axis by a W polar angle that is sufficient to position said W thruster between said NW and SW thrusters and rotated westward from said yaw axis by a W slew angle that is less than 80.degree..