Discovery and its Science Channel affiliate will air tributes to astronaut Neil Armstrong, who died last week. The first man to set foot on the moon, Armstrong is probably best remembered and appreciated for his avoidance of the limelight in the years since his Apollo spaceflight in July 1969. Although it seems trite to reduce his achievement to mere television, Armstrong can be seen as the “star” of the most widely watched event in the history of the medium. That he returned to a rather private life afterward speaks volumes about his character.

”One Giant Leap: A Neil Armstrong Tribute” (7 p.m. Saturday, Discovery; 9 p.m., Science) includes archival clips of the Apollo project and interviews with Armstrong and his fellow astronauts. The 2007 documentary “In the Shadow of the Moon” (7 p.m. Saturday, Science) also looks at the incomparable effort to put a man on the moon that began with President John F. Kennedy’s 1961 challenge and culminated with Armstrong’s “one small step” eight years later.

Discovery will also air the 2008 film “When We Left Earth” (6 p.m. Saturday), narrated by Gary Sinise. The film puts great emphasis on the unknowns surrounding the mission to the moon. Rocket science and physics told NASA that it could get there, but there was no certainty of surviving a landing on the lunar surface or successfully returning to Earth.

• Cesar Millan takes a victory lap of sorts through his final season of “The Dog Whisperer” (7 p.m. Saturday, Nat Geo Wild). He visits, and trains, the dogs of NASCAR drivers and their families.

It’s hard not to associate the stock car circuit with a certain machismo. Take for instance, Saturday’s race, the NRA American Warrior 300 (6 p.m., ESPN2). But two of the most notable dogs featured on “Whisperer” are very small. Millan interviews drivers and their families who have the toy breeds because they acclimate better to the trailers they live in while traveling from race to race.

A concluding segment showcases driver Greg Biffle and his wife’s efforts to spread the word about spaying and neutering dogs to keep unwanted animals from being sheltered and destroyed.

Saturday’s other highlights

• On two episodes of “48 Hours Mystery” (CBS): tempting fate (8 p.m.) and honor (9 p.m.).

• A radical procedure may awaken Charlie before he’s ready on “Saving Hope” (8 p.m., NBC).

• The doctor is incarcerated in a dangerous outer space prison on “Doctor Who” (8 p.m., BBC America), the first of five new episodes.