The Hitchhiker's Guide to the Galaxy - Season 1 - Episode 3
The starship Heart of Gold is headed for the planet Magrathea, a planet which it is generally agreed does not exist. In trying to land on Magrathea's surface, the crew faces an ancient nuclear missile defence system, escaping only when Arthur turns on the Infinite Improbability Drive. This helpfully replaces the missiles with a bowl of petunias and a very surprised sperm whale, who learns about the ground before he hits it. Later on, deep in the core of the planet, an unknown enemy attacks Trillian, Zaphod and Ford while Arthur meets Slartibartfast, an old man who designs planets for a living. Slartibartfast takes Arthur on a tour of the factory floor, showing off his latest project - Planet Earth, Mark Two.
About The Hitchhiker's Guide to the Galaxy

Title: The Hitchhiker's Guide to the Galaxy
First Air Date: 1981-01-05
Last Air Date: 1981-02-09
Status: Ended
Rating: 8/10 (from 32 votes)
Language: EN
Seasons: 2
Total Episodes: 6
Network: BBC Two
Genres: Comedy, Sci-Fi & Fantasy
Production Companies: BBC
Synopsis
Don't Panic! The story of Arthur Dent, an average Englishman who life was spared by his friend, who turned out to be an alien, while the planet Earth is destroyed. His friend tells him about the Hitchhiker's Guide to the Galaxy, a guide with anything you ever needed, and wanted to know. They travel across the galaxy, meeting friendly, and not so friendly characters in order to find the great question (the answer being 42).
Cast

Simon Jones
Arthur Dent

David Dixon
Ford Prefect

Sandra Dickinson
Trillian

Mark Wing-Davey
Zaphod Beeblebrox

Stephen Moore
Marvin (voice)

Peter Jones
The Book

David Learner
Marvin