I'm a big fan of space movies, especially when they're based on actual science and/or near-future. So of course I went to see Ad Astra (IMDB). In a nutshell, Brad Pitt's character flies into an orbit around Neptune on a rescue mission. This involved flying to the Moon to get on a rocket to Mars then blast off in a heavy rocket to make the actual trip.
My main issue with the movie was that, according to my limited understanding of space exploration (primarily thanks to KSP), the Moon would offer a better launch as the thrust requirements to get back into space should be significantly lower than Mars. My girlfriend's argument, somewhat as devil's advocate, is that Mars is better because it's closer to Neptune. The only reason I can think of to use Mars instead of the Moon is if the transfer window for Earth-Neptune is closed but Earth-Mars is good and Mars-Neptune is also good.
Which location would serve better for deep space vehicles, the Moon or Mars?