A spacecraft power/sun acquisition method includes a pitch search phase in
which the spacecraft is rotated about a pitch axis, stopped, quaternions
reset to remember position, and yaw search phase is entered when a first
TOA occurs from a first slit sun sensor, and a keyhole slew is performed
when the first TOA does not occur. The method also includes yaw search
phase in which a keyhole slew is performed by rotating the spacecraft
about a yaw axis, stopping the spacecraft, and entering pitch search phase
when the first TOA does not occur, and in which the spacecraft is rotated
about a yaw axis, stopped, quaternions reset, and sun hold phase is
entered when a second TOA occurs from a second slit sun sensor. Lastly,
the method includes a sun hold phase in which the spacecraft is oriented
to the sun and placed in spin at power safe attitude.