Replay
Rewind any orbit, any epoch, frame by frame.
Rewind the sky
Missed a conjunction? Want to see where a satellite was the moment a photo was taken? Replay pulls historical ephemerides and re-runs the sky for any moment you choose.
What replay does
input any UTC timestamp source archived TLE history output a rendered frame of the sky, then scrub play forward or back at any speed
For the investigators
Astrophotographers use it to trace a streak back to its object. Historians use it to confirm "what was that light?" We just think it's beautiful to watch the past move.