The purpose of many spacecraft is to observe and/or communicate with
subjects on or near the surface of the Earth.
The visibility of a subject from a spacecraft will depend both on the
location of the subject and the type of orbit that the spacecraft is
The orbit can be altered if propulsion is available on the spacecraft.
When dealing with multiple spacecraft working together (as in a
constellation) an optimization can be performed to determine
which spacecraft should alter their orbit by how much. This research is
To visually inspect the results of the research, I extended my prior Orbital Simulation
to arrive at a spacecraft simulator
which has been quite valuable at better understanding the geometries
and orbital maneuvering.