The starship Heart of Gold is a spaceship which is featured in 'The Hitchhiker's Guide to the Galaxy'. Its main feature is that its propulsion systems works through an Infinite Improbability Drive.
This starship is the first to make use of an Infinite Improbability Drive, and also features top of the range Genuine People Personalities (or GPPs), courtesy of the Sirius Cybernetics Corporation, who are known for being an inept company that creates largely useless devices.
It was stolen and subsequently piloted by Zaphod Beeblebrox, President of the Galaxy, at its official launch event.
Genuine People Personalities
The Heart of Gold features several products with GPPs (Genuine People Personalities), which imbues them with intelligence and emotion. All of the doors on the ship open and close rather happily, thanking those on board for using them and traveling through them. The starship is also fitted with a Nutrimatic drink dispenser, which does not understand why anyone would want a cup of tea, a ventilation system which fills the air with a scent that Arthur Dent said smelt like 'cheap perfume', and a floor which attempts to use gentle vibrations to soothe its crew.
Eddie, the onboard ship computer, has an exceptionally cheery personality, even when the ship is being faced with almost certain doom. He does have an alternate personality option which is similar to that of a boarding school headmistress or matron.
The starship also includes a prototype version of the GPP software, Marvin the android, who is part of a range of robots that were advertised as 'your plastic pal who's fun to be with'. Conversely, Marvin is manically depressed, often frustrated, and occasionally suicidal.
Infinite Improbability Device
The Heart of Gold is fitted with an Infinite Improbability Drive, which is a method of traveling through space by passing through every conceivable point in every conceivable universe simultaneously. A side-effect of its use is that anything that is in any way probable can happen once the drive is used, such as turning someone into a penguin, or causing a team of seven three-foot-high market analysts to fall from a hole in the universe and die from a combination of asphyxiation and surprise. These side-effects can be temporary or permanent, there is often no way of knowing (or guessing the probability of such events).