Filming was hard on the actors: James Garner dislocated his shoulder, and Donald Sutherland cracked a knee.
Clint Eastwood was initially just going to star in and produce this movie, not direct it. After potential directors thought filming space travel would be too difficult, he decided to do it himself.
As it approaches the Kennedy Space Center, the Daedalus Orbiter makes a double sonic boom. This is because the Orbiter creates two shock waves, the bow wave and the tail wave, which are heard as separate "booms".
According to Adam Savage, in order to replicate the appearance of gold foil on camera, the special effects team tested various materials and found that the gold-colored wrappers of Rolo candies worked best.
N.A.S.A. offered their "vomit comet" plane that can create weightlessness, for filming (it was previously used in Apollo 13 (1995) for the weightless scenes). Clint Eastwood turned down the offer for fear that the older actors would be made too sick to film.