While planning the famous EVA rescue scene (in which an oxygen bottle is used as a makeshift propulsion unit) the film makers considered using a shotgun as the means by which John Archer retrieves Warner Anderson when he drifts away from the rocket in space. Thankfully they changed their minds; a shotgun seems like an inappropriate piece of equipment to take to a lifeless, airless satellite. However, the shotgun concept was used in the final film during Woody Woodpecker's cartoon demonstration of rocket propulsion which is shown to the millionaire industrialist who finances the Moon trip.
I know one thing: unless these pills work, space travel isn't going to be... popular.
The astronauts go outside the ship to unfreeze a stuck antenna. When one goes adrift and has to be rescued, he is rescued using an oxygen bottle as a makeshift rocket. They go inside without any repair of the antenna being shown.
At the end of the film, a story of the first flight to the Moon, the words THIS IS THE END are displayed first, then OF THE BEGINNING is added.