predicting closest approach between Earth and Mars

[cdeaglejr]

This HP Prime program can be used to predict closest approach between the Earth and Mars. The software will interactively request user inputs for an initial calendar year and a search duration in days.

The code will calculate and print the calendar date, UTC time and the Earth-to-Mars distance in both astronomical units and kilometers for any minima found during the search.

[StephenG1CMZ]

Since there are rovers on Mars, it would also be interesting to see the distance in light-time.