This DOS program maintains its own satellite database of up to 20,000 sats. This allows the user to sort satellites into groups of their own choosing. The database can be quickly updated from any TLE file including the large files provided by Molczan, McCants or Thomson. The program can fly up to 200 sats simultaneously. A large part of STK has an orbital analysis suite.
Registration is required.
AGI hopes to make its STK software a reference tool for space industry worldwide. SatEvo Alan Pickup produced a program that computes the decay and re-entry time of earth satellites. Mir Alphonse Pouplier's DOS program tracks a given satellite across the star filled sky in real time making this program especially useful for beginner observers. Iridium Flares Randy John and Rob Matson have separately developed their own DOS programs that will predict reflective flares from the Iridium satellites. The above link will take you to their respective links and information on viewing the Iridium satellites.