"You must have a pretty big building to fly these around in."

The above is (so I'm told) a genuine quote from a guest after riding Star Tours at Disneyland in California. You may laugh, but it goes to show just how convincing this attraction was in its early days. So, how does it work?

The simplest element to describe is the actual motion simulation side. To move your vehicle (medical transport vessel or Starspeeder 3000), a number of hydraulic rams positioned underneath the vehicle move up or down in synchronization, to tilt the ride vehicle in the necessary direction. The current system has 3 degrees of freedom of motion (directions in which the simulator can move). But if George Lucas gets his way with Star Tours 2, the new system will have 10 degrees of freedom for a very realistic ride! The synchronization between these movements and the sound and video inside the vehicle create the sensation of motion. But just how is everything synchronized?

To answer this, we have to consider the one element in the vehicle that is operational throughout the whole ride, the little video monitors next to the exit doors. These are in fact connected to a laserdisc system in the old vehicles (Body Wars) and a normal PC in the updated vehicles (Star Tours).As well as showing the necessary video during the ride, the systems are communicating data through a serial link (older vehicles managed this by encoding the data as another soundtrack on the disc, which sounded a lot like a modem does when hooked up to a phone line) to the various components, and helps to synchronize the countdown timer in the preshow area (a duplicate of the ride system, but less complicated). In Star Tours, as well as the shield, lighting and hydraulics, the system also controls the animatronic Rex.

As for the panel the cast member opens at the start of the ride, that's just an indicator board triggered by sensors in the safety restraint system, each green light represents a belt that has been fastened. The belts are then locked in place with pneumatics (listen for the hissing noise when this happens), and the ride can start.

By the way, the motion data for Star Tours was worked out by one of the ILM people sitting in the middle of a Starspeeder, watching the film and moving a joystick in time with the film. This original version lasted about 20 minutes, was cut to about 4 minutes because test audiences were getting nauseous, then put back to about 5 minutes so people wouldn't feel ripped off after queuing!

photos by Jim Hartung