Twilight's Fall – a separate game. Twilight Imperium's expansions, mods and rules topics are not part of it.

Gauss Cannon I

This unit is placed in a space area instead of on a planet. This unit can move and retreat as if it were a ship. This unit can be blockaded, if it is blockaded, it is destroyed.
Mirveda ProtectorateUnit – Structure – PDS

PDS

This unit is placed in a space area instead of on a planet. This unit can move and retreat as if it were a ship. This unit can be blockaded, if it is blockaded, it is destroyed.

SPACE CANNON 6 · BOMBARDMENT 6

1move
Upgrades toGauss Cannon IIRequires WarfareCybernetic

Source: Discordant Stars