Humanity's conquest of Mars became a reality with the Viking missions of the 1970s, and some experts believe that evidence gathered from these incredible explorations proves that there was once life on the Red Planet.
| Name | Type | Role | |
|---|---|---|---|
| Everett Gibson | Guest Star | ||
| John Casani | Guest Star | ||
| Ken Clark (NASA Scientist) | Guest Star | ||
| Tanya Harrison | Guest Star | ||
| Richard Grumm | Guest Star | ||
| Gentry Lee | Guest Star | ||
| Matthew Golombek | Guest Star | ||
| Rod Pyle | Guest Star | ||
| Gilbert Levin | Guest Star | ||
| James Green | Guest Star | NASA Chief Scientist | |
| Mike Carr | Guest Star | ||
| Patricia Ann Straat | Guest Star | ||
| James Garvin | Guest Star |