How accurate is NASA SkyWatch?
NASA SkyWatch has a high fidelity numerical integrator along with very accurate acquisition classes that take into account orbital drag and gravity effects of the sun and moon on the satellite. However, the results are only as accurate as the inputs you provide. The most critical input is the state vector. NASA maintains vectors for ISS and the space shuttle and using vectors that are provided by NASA SkyWatch is highly recommended. If you decide to use your own vector or two-line element set, the most recent vector available should be used. Since vector accuracy will degrade over time, vectors more than a week old should be discarded in favor of more up to date data. Translational maneuvers (orbit shaping) should also be accounted for. If you retrieve a vector for ISS or the space shuttle, maneuvers are already accounted for. If you manually input a vector, no maneuvers will be implemented and results may be significantly in error if the vehicle either raises or lowers its orbit. This
