A simple, robust algorithm for power acquisition for power, thermal, and
momentum safety for high heater-power spacecraft uses current sensors
rather than sun sensors and includes a wing sun search phase, an xz slew
phase, and a safe hold phase. Solar wing current is continuously monitored
against a high current threshold and a low current threshold. Wing sun
search phase transitions either to xz slew phase or safe hold phase. When
current is too low, the xz slew phase is entered and slews the spacecraft
about an axis in the xz plane until current is high enough. When current
is high enough, the algorithm transitions or remains in safe hold phase
and the spacecraft is spun about its wing axis. A low current persistence
timer is longer than a high current persistence timer in order to bias the
algorithm to prefer safe hold phase over xz slew phase.