During the period this movie was being made and released, CIA agent Aldrich Ames was beginning to engage in his espionage activities, selling secrets to the Soviet Union. In 1998 these events would be dramatized in Aldrich Ames: Traitor Within (1998), which also starred Timothy Hutton in the role of Aldrich Ames.
In 1986, this movie became associated with one of the most famous hacking incidents in television history. On the night of April 27, 1986 at about 12:30am, a Florida satellite TV dealer named John MacDougall was working late at Central Florida Teleport which up-links pay cable services to satellites. At the time, he was up-linking Pee-wee's Big Adventure (1985) but before he left, he pointed the dish directly upwards toward the location of HBO's Galaxy 1 satellite and for four and a half minutes, East Coast subscribers who had been watching The Falcon and the Snowman saw a message on a colored test pattern which read: GOODEVENINGHBO FROM CAPTAIN MIDNIGHT $12.95/MONTH? NO WAY! [SHOWTIME/MOVIECHANNEL BEWARE!]. MacDougall had performed the stunt as a protest of satellite subscribers being forced to pay higher fees than regular cable subscribers. He turned himself in, was charged a $5,000 fine and placed on one year probation.
Timothy Hutton spent six months in Santa Cruz, California learning falconry with technical advisor John Moran. Moreover, Hutton also studied countless press clippings from Christopher Boyce's trial and watched hours of television interviews with Boyce as well as visiting Boyce at Marion Penitentiary in Illinois as research for his role.
Christopher Boyce uses a numeric cipher to send messages to the Soviets while keeping Daulton Lee unaware of their meaning. The cipher is nearly identical to the one the real Boyce used for this purpose (described by Robert Lindsey in his book, upon which this movie is based). In the movie, Boyce's cipher works like this. First, number the alphabet's letters sequentially - e.g., A = 1, G = 7, Y = 25. Second, multiply these numbers by seven (A, G, and Y become 7, 49, and 175 respectively). Finally, reverse the digits (so A, G, Y become 7, 94, and 571). The message Boyce photographs in his bathroom decrypts to "good will towards men the falcon"; and while his earlier encrypted message that "the courier is undependable" is more or less gibberish (perhaps because he's still calculating it), the last few numbers decrypt to "falcon." The real Boyce's cipher differed only in that the first step was to assign numbers to letters in reverse order - i.e., Z = 1, Y = 2, et cetera - but from there proceeds identically. Boyce did not receive instructions from the Soviets but invented this cipher himself, reasoning that it would be child's play for the Soviets to break but beyond Lee's ability to decrypt.
Sean Penn underwent a substantial physical transformation for his role as Andrew Daulton Lee: Penn wore deep blue contact lenses, trimmed his eyebrows back in a straight line with his eyes, used a set of dentures to make his teeth identical to Lee's, used nose spreaders to make his nose broader, grew a mustache, and even gained about fifty to twenty pounds.
When Daulton Lee hands over the envelope to the Soviets they are surprised to find photos of a partially nude woman. The photos are of Nancie Li Brandi, Playboy's Playmate of the Month for December 1975.
The trivia items below may give away important plot points.
The movie is based on actual events, but the character of Christopher Boyce is portrayed as a "white knight" fighting the system because he was disillusioned by Nixon-era foreign policy. Daulton Lee, on the other hand, is shown as a mentally unstable drug addict motivated only by money. After serving his prison sentence, Lee did not reoffend. Boyce, however, escaped from prison and went on a bank-robbing spree in the Pacific Northwest. These real life facts bring tarnish to the white knight's armor which was not included in the movie.
In this film Timothy Hutton's character is an American convicted of being of espionage acts while selling information to USSR. In Daniel (1983), he plays the son of a couple (based on Julius and Ethel Rosenberg) tried and convicted of similar acts he commits in this film.