Originally Posted by Larry Jacks

For one thing, Ron Howard used actual weightlessness to show weightlessness. Those weightless scenes were filmed in the Vomet Comet*. Second, while the movie did contain some errors, it's probably the most accurate representation of space flight ever presented in a non-documentary film. In all, it was an excellent movie. That's just my opinion, of course.

*Think of the challenges this presented. The weightlessness only lasts for about 45 seconds, so the actors had to very quickly hit their marks and do the required actions and say their lines before they were hit with a roughly 2G pullout. It took dozens of arcs (I've heard it was over 100) to shoot all of the scenes. That alone is a pretty remarkable piece of film work, IMO.