An S3 Planet (Solar Three Planet) was the Space Corps designation for any planetoid or planetary body in the Galaxy that has a similar atmosphere and conditions to Earth.
Classification
The classification evokes the placing and conditions of the homeworld of humans as the third planet from its star, within the habitable zone, the same as Earth in its own solar system.
However, an S3 Planet does not have to necessarily be the third planet from its star to fall into the designation, or even be a planet at all, as long as it can support human life on the surface. An S3 Planet could be a whole planet, a rocky moon, an ocean moon, or even an asteroid, if the planetary body has enough gravitational pull to hold onto a suitable atmosphere.
S3 planetoids encountered by Red Dwarf
- Earth - visited by the boys from the Dwarf numerous times, including "Backwards", "Timeslides", "Tikka To Ride", "Ouroboros", "Back to Earth", "Lemons" and "Twentica"
- The barren, rocky planetoid where Arnold Rimmer's Deathday party was held - "Thanks for the Memory"
- Unnamed snowy planet - "Marooned"
- Ocean moon - "Dimension Jump"
- Waxworld - "Meltdown"
- Psi-moon - "Terrorform"
- Lanstrom's planet - "Quarantine"
- Ocean planet - "Back to Reality"
- Asteroid - "Psirens"
- Kinitawowi GELF moon with gloomy, swamps and ocean - "Emohawk"
- Rimmerworld, a planet terraformed by Rimmer and populated by his clones - "Rimmerworld"
- A pale-green Brefewino GELF planet with three bright moons - "Identity Within"
- Delta VII. Although it is no longer an S3 Planet, it once was - "Epideme"
- The Red Dwarf planetoid which had once been Red Dwarf - "Nanarchy"
- Unnamed snowy BEGG moon - "Entangled"
- Io moon - "The Beginning"
- Mimas - Infinity Welcomes Careful Drivers novel
- Lotomi 5 - Last Human novel
There were several other planets visited by the Dwarfers, but they were not shown or mentioned explicitly to be S3 planets. There were also several crashed vessels and bases on planetary surfaces, but the atmospheres breathed by the crew may have been from the ship or base rather than the planet itself.
Non-S3 Planets
An example of a non-S3 planet visited by the Boys from the Dwarf would be the lava moon or Traga 16.