  This paper introduces an algorithm to perform optimal reorientation of a
spacecraft during a high speed flyby mission that maximizes the time a certain
target is kept within the field of view of scientific instruments. The method
directly handles the nonlinear dynamics of the spacecraft, sun exclusion
constraint, torque and momentum limits on the reaction wheels as well as
potential faults in these actuators. A sequential convex programming approach
was used to reformulate non-convex pointing objectives and other constraints in
terms of a series of novel convex cardinality minimization problems. These
subproblems were then efficiently solved even on limited hardware resources
using convex programming solvers implementing second-order conic constraints.
The proposed method was applied to a scenario that involved maximizing the
science time for the upcoming Comet Interceptor flyby mission developed by the
European Space Agency. Extensive simulation results demonstrate the capability
of the approach to generate viable trajectories even in the presence of
reaction wheel failures or prior dust particle impacts.
