The classic DOS satellite tracking program InstantTrack by Franklin Antonio, N6NKF (and later maintained by me, Paul Williamson, KB5MU) is now free to download and distribute. See http://instanttrack.com for download links, documentation, and related files.
The latest version remains 1.55, released as an open beta on May 12, 2002. InstantTrack is still a plain old-style 16-bit DOS program. It ran under Windows up to Windows XP or so, but won't run directly on recent versions of Windows. It can still be run on nearly any computer by using DOSBOX.
From its initial release in November 1989, InstantTrack was sold by
AMSAT-NA and other AMSAT organizations around the world as a fundraiser. All proceeds from InstantTrack went to support the amateur satellite program. This income stream has dwindled to a tiny trickle, and all the AMSAT organizations (as far as I know) stopped offering InstantTrack years ago. It was still available online through one of the old-school shareware fulfillment sites, until that site went offline recently. Rather than rehost InstantTrack for sale on another platform, Franklin and I have agreed to release it for free download and distribution.
73 -Paul KB5MU