Class U planets represent the upper limits of planetary masses. Most exist within a star system's Cold Zone and are very similar to Class S and J planets. However, Class U planets occasionally form within a star system's Hot Zone. If they are sufficiently massive (13 times more massive than Jupiter), deuterium ignites nuclear fusion within the core, and the planet becomes a red dwarf star, creating a binary star system.

Class U Planet type

Game Notes:

  • Extreme attrition damage to units outside Pressure Domed facilities.
  • Due to nature of surface, ground combat on surface is impossible (100% attrition to units forced to land on planet)
  • No Water for Naval Units
  • No Water for Fishery or Waterport
  • Extreme Atmosphere, Air Units only 25% effective.
  • Facilities can not function here unless they have the Repulsorlift Upgrade, immediately destroyed on surface.
  • Facilities can not function here unless they have the Pressure Dome Upgrade, or suffer damage.
  • Facilities can not be constructed here, they must be transported here.
  • Mines do no produce anything.
  • Gas Mine produce x2 Energy.
  • Extreme Weather Events.
  • Risk of becoming a Star.