In "The Martian", Rich Parnell uses a supercomputer to calculate a life saving slingshot trajectory that allows Watney to be saved.
The entire film is renowned for its scientific care, so I was really surprised at this. The Hermes is travelling between Earth and Mars, so even allowing for an extended journey and slingshot, there are very few bodies that are materially relevant to its journey. The time scale is short by cosmology standards. Flight and delta-v calculations don't seem like they need supercomputing capability for something like this, as the calculations just don't seem complex enough to need that level of resources. The main question would be risk evaluation (excess fuel, risk of incidents) not trajectory calculations or simple flight viability.
Would a calculation like this really have needed a supercomputer? It seems like something that wouldn't be unreasonable to expect to be calculable on a much more mundane computer.
Hard science answers appreciated! It won't spoil the film to be told if this was a minor exaggeration for effect, or to learn it's actually a lot harder in real life than it seems!