HP 48 Series -- interseries compatibility?

[johnb]

The best part (for HP fans) is when I present a scene from "Rocket Girls."

A young prospective astronaut is in a classroom, and they're covering Hohmann transfer orbits (and the equations on the whiteboard in the scene are correct!)

The prof asks her for the value of a couple of variables. "Use your calculator!"

And she says, "What the Heck? This calculator has no equals key!"

And they've clearly rendered an HP-41cv.