3.3 Holodecks: Theory and Operation

Holodecks: Theory and Operation

The text presented below is offered as background material developed by Gene Roddenberry, Bob Justman, Andy Probert, Mike Okuda and Rick Sternbach. As with all our technology, it is offered as an aid in developing story situations.

From the early days of manned space exploration, it was apparent that long-duration space flights would require that certain measures be taken to keep the travellers happy and psychologically fit for continued duty.

The Mercury and Gemini astronauts brought along cassette tapes of their favorite music, and Mission Control periodically passed up capsule versions of the daily newspapers. Today, on the Space Shuttle (to a limited extent), and soon on the Space Station, documents may be transmitted to onboard printers and video material can be sent up and recorded. A little bit of home away from home, indeed.

Now, in the 24th Century. Here we are in the 24th Century. Information storage and retrieval systems are sophisticated beyond our imaginations. Well, almost. We can imagine quite a lot.

The powers that be on this show have had the foresight to provide the Enterprise with the ultimate in synthesized recreational systems, the Holodeck. We talked to Starfleet R&D to get a detailed description of the device and possible options/improvements.

The fact sheet says that the basic mechanism behind the Holodeck is the Omnidirectional Holo Diode. This is a miniature gizmo that projects a variety of special electromagnetic (or EM) fields. One hundred of them would fit in the same space as a single LED of the 1980s.

Entire walls are covered with tens of millions of OHDs, since they are manufactured in an inexpensive wide-roll circuit printing process. Dedicated high-speed computers, highly intelligent and with massive memories, drive these OHD displays much like computers drive video monitors today, even the ones with limited 3-D stereo display capability (actually available on some home computers). Which is where the similarity ends.

In addition to their ability to project full-color stereoscopic images, OHDs can manipulate EM fields in three dimensions to cause the Holodeck visitor to “feel” objects that aren't really there. This tactile stimulation provides the proper feedback the visitor might expect from, say, a rock on the ground or a tree growing in an imaginary forest. The only limiting factors to the number and kinds of objects so described by the Holodeck computers are memory and time to record (or calculate from scratch) the originals of the desired objects, be they models of real objects, or even objects that couldn't possibly exist in this universe; i.e. Klein bottles. More about the EM fields in a minute.

Other stimuli, such as sound, smell, and taste can be simulated by more traditional methods (speakers, atomizers, etc.). These will also be under computer control.

In some cases, real objects are created from a raw material supply, using technology derived from the ship's transporter. These objects may appear complex in shape, though their actual molecular structure cannot be complex (as in living tissue, etc.), due to the limitations inherent in transporter memory storage devices (see separate article on the transporter).

The optic section of an OHD emits a complete image of an overall environment, but the visitor sees only a tiny portion of any one OHD, like a fly's eye operating in reverse. As one moves around, the visible portions of the OHDs change, altering the view. The OHDs don't actually emit pictures like a film projector, but polarized interference patterns. The image is reconstructed where the patterns intersect at the lens of the eye. Since the right and left eyes see slightly different views, we can see depth. Admittedly, the system is almost purely Magic Box technology, so this explanation isn't 100% verifiable. But hey....

The EM field section of an OHD creates a tiny steerable forcefield. We will know their big cousins as the tractor beam and navigational deflector. Under computer control, and over a vast number of OHDs, this can add up to something terrific. Imagine we know the surface coordinates of a rock. The computer driving the Holodeck will command certain OHDs to intersect their fields at those coordinates. If the field strength is high enough to say “rock”, it feels like rock. If it is tuned down a touch, it feels like sandstone. Lower, it feels like Jello. Get the idea? Various substances can be simulated, even water. Even fog on little cat feet.

What this gives us is the power to create terrain, structures, atmosphere — complete sensory environments. Things to walk over, sit on, swim under, or fly above. Combined with certain parts of a simulation being created by transporter technology, the holodeck provides a complete distraction.

In our short discussion, a lot of ideas came out. Specific areas, perhaps small rooms outfitted with holo equipment, could be one-person “POV Cubicles”. Walk through a forest, on a beach, or into a volcano. Fly a hang glider or practice EVA spacewalks. The treadmill is obsolete in this day and age, since the shaped EM fields will allow the visitor to move as fast as he or she can run by instantly sliding the imaginary terrain beneath the feet. The exact texture of sand, grass, concrete, rock, or steel is duplicated, depending on the resolution and density of the field.

The fields, being movable, can even simulate birds, animals, toys, other people, robots, flying saucers, or pink elephants. You could skim an imaginary stone on an equally imaginary lake. Or ride a dragon, complete with leathery wings and fiery breath.

Larger areas would be sized to accomodate groups of people, all experiencing the same environment. The larger areas would be bounded by the deck's walls, of course, but these could be cleverly disguised by things like rock walls, corral fences, sea cliffs, and the like. If you were getting close to the real walls, you might hear a soft but recognizable beep to get you back to the main illusion. Entries to the holo area could be simple standardized arches or doorways. (In fact, we have already seen rocks bounce off the wall).

In an environment like a Federation starship, where safety is of prime importance and is engineered into every system, it will be necessary to allow the Holodeck visitor to believe — sometimes — that there may be dangers to be faced. More than a few thrillseekers will slip through Starfleet psych profile computers, and they will want to do more than take a leisurely stroll or hit a bucket of golf balls. Recreational fighter jocks and mountain climbers with marginal equipment will love the experience, and then go back to being clerk, cook, or captain. The Holodeck programmers might slip in a shark the next time you go swimming off the Australian north coast.