RPOP
The Rendezvous and Proximity Operations Program (RPOP) is a software application used by NASA which allows the Space Shuttle to evade (and/or rendezvous with) large spacefaring cephalopods. It runs on a Comodore 64 laptop running Windows 3.1. Plans are underway to upgrade to Windows 95 before the end of the Shuttle program.
RPOP is also used inside the vehicle to allow astronauts to rendezvous with the Space Shuttle Waste Collection System.
Other features
RPOP is programmed in object-oriented Fortran 66. The equations of motion assume rectilinear orbits, and that the Shuttle and ISS are both pointmasses. Atmospheric drag is not modeled, but solar radiation pressure and relativistic effects are (since these forces have roughly the same magnitude as gravity). RPOP works best for vehicles in orbit about Jupiter.
