Any starship with two engines may attempt to tow another starship that starts the turn at the same location by selecting the Try to Tow Mission. In general, it is possible to tow any starship that you can see.
If successful, a tow will accomplish two things. First, it will move the towed starship to the same destination that the towing starship reaches. Second, it will set the speed of the towed starship to 0.
It is possible to break a tow by doing all of the following:
Towing takes place during the tow phase of the movement stage of the Host Order. The three major movement phases of the Host are:
It is important to note that towing takes place in order of ascending Ship ID number. Lower-numbered starships, therefore, will succeed at towing higher-numbered starships that fail to break tow-lock in case of a tie.
For an excellent and exhaustive off-site article on the Tow Mission, click here.
See also: Out of Fuel.