FWIW…
While watching a recording of yesterday's (1/6/04) PBS Nova show about the NASA Mars lander, I saw a 2 or 3 second view of a calculator on the worktable. The machine was partially obscured by papers on top of the upper third of the machine. Unfortunately, it appears to not have been an HP. Judging from size, coloring, and arrangement of buttons, my best guess is that it was a 1992 TI-36X SOLAR, or possibly a 1991 TI-35X.
For others who may have a recording of the show, the scene in question took place about 37 minutes into the show (I say "about" because my recording did not begin at the exact beginning of the show.), just after they discovered "squidding" problems in their parachute.
Larry