Filming was hard on the actors: James Garner dislocated his shoulder, and Donald Sutherland cracked a knee.
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.
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".
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.
The Mission Control set was built using blueprints of the real Mission Control, provided by N.A.S.A.