The Missile Tubes are a so-called dumb fire missiles. These missiles will only fly in a straight line after being fired unless it has Support Weapons. These missiles without Support Weapons are meant for striking stationary targets, like space stations , asteroids or planets. On multiplayer these could also work against large and slow ships.
The Missile Tube is sold at every shop for 300c.
Like with all the other weapon systems in StarMade, the Missile Tube profits from a group. Meaning, the more Tubes you connect to each other, the better the missile will be. A big group will offer a larger blast radius, higher damage, faster speed, longer range and shorter reload.
The Missile Tube needs to be linked to a Missile Computer on your vessel. Without the Computer, you will not be able to use the Missile Tubes. Once you place a Computer and add the Tubes, you can see if they are linked. Once the Tubes get a purple outline, they are linked. By pressing T you can add the Missile Tube to your hotbar.