In the film, the four astronauts appear together on "The Tonight Show with Jay Leno" (1992). To promote the film, they all appeared together on the same show.
The night scenes where Tommy Lee Jones and Marcia Gay Harden are alone together was filmed in the University of Houston - Downtown campus satellite parking lot; permission from the university was needed to film the night scenes. Clint Eastwood met with UHD president Dr. Maximillian Castillo in person in late 1998 before filming began.
Clint Eastwood wrote the theme that plays at the beginning of the movie and it was worked into the score by Lennie Niehaus.
The modeling department put a Space Mr. Coffee in the cargo bay of the shuttle. This was the idea of chief modelmaker 'Adam Savage (II)', now co-host of _"MythBusters" (2003)_ on the Discovery Channel.
Originally Sean Connery was supposed to play Jerry O"Neil and Jack Nicholson was supposed to play Tank Sullivan.
Chosen by "Les Cahiers du cinéma" (France) as one of the 10 best pictures of 2000 (#09)
The film opened the Venice Film Festival in 2000.
According to film editor Joel Cox, director Eastwood, a notoriously quick director, would routinely film as many as 35 to 40 set-ups in a single day.
Tommy Lee Jones is seen wearing a "Cowboy Bar" shirt which is from the Million Dollar Cowboy Bar in Jackson, Wyoming. This was a favorite bar for Clint Eastwood and where he shot one of his last scenes in Any Which Way You Can (1980).
NASA 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.