Public Domain Aeronautical Software (PDAS)  

This program evaluates the communications link between the Viking Orbiter and Lander vehicles. The program calculates the trajectory of the Orbiter and Lander simultaneously. Using data from both vehicles, this program calculates communication geometry. (Martin Marietta Corp. for NASA Langley)

This program was released by NASA through COSMIC as LAR-10658. The italicized text above is from the official NASA release.

Public Domain Aeronautical Software (PDAS)