Lunar Lander (LEM) – original BASIC/FOCAL version

One of the most popular games of the late 1970’s was Lunar Lander (also known as Rocket, LEM, Apollo and what-have-you). The general idea was always to land a Lunar Excursion Module (LEM) on the surface of the moon (or other planet) by adjusting the burn rate of retro-rockets in order to control deceleration and effect a nice soft touchdown.

The version presented here uses a set of calculations based on a program called LUNAR written by Jim Storer for the PDP-8 while a student at Lexington High School in the USA in 1969. It was converted from the original FOCAL into BASIC by Dave Ahl (then publisher of Creative Computing magazine) in the late 1973.

As far as I can tell, I have disentangled the calculations well enough to preserve the original’s look-and-feel, though it required a complete re-write for Java (which does not support the GOTO statement for program logic flow control). I couldn’t say that the calculations are accurate to life, but a good attempt at realism was made in the original. If anyone from NASA would care to comment please drop me a note.

You will need to click on the window in order to use the keyboard.

Leave a Reply

Your email address will not be published. Required fields are marked *