Chapter 10: Lifters
By lifters we mean unconventional methods of levitating a craft (conventional means include lifting gasses, airframes, rotors, and conventional thrusters). The standard lifter used in Traveller is the contra-gravity device found on most spacecraft. Several alternative lifters are described later in the chapter.
It should be noted that two other alternative lifter technologies — the Dean Drive and thruster plates — are included in the Sublight Drive chapter (Section 9) as they are also useful for interplanetary travel.
Contra-Grav
Ducted Fans
Maglev
The contra-grav lifters described in the game are far from the only imaginable means of manipulating gravity, and of the various types imaginable, one the more interesting we call a gravitic displacement (GD) field. A GD field displaces the potential energy of a mass toward the closest gravity source without moving the mass itself, thus circumventing gravity with respect to the physical mass. This allows a massive object to rise and hover, and has much the same effect as contra-grav. The technical requirements of GD fields are similar enough to those of contra-grav
Liftwood (Space 1889)