Vol. 16, No. 3, Oct-December 2005 

Show Basics, The Lighter Side:
Are There Beam Shows in Outer Space?
By David Lytle, Editor, The Laserist

It sounds like the tag line for a bad science fiction movie (and probably is): In outer space, no one can hear you scream!

The blood-curdling screams of the female herioine will fall silent because space is a vacuum, and sounds can't travel in a vacuum. It's not a big loss for me. We can cope with the problem easily enough by piping sound into our space helmets and listening to the latest re-issue of Wish You Were Here, so it's not the end of the world.

For the end of the world, consider this sci-fi movie tag line: In space, no one can see laser beam shows!

I realize how scary this thought is, so take a moment to calm yourself. You were probably looking forward to the prospect of interplanetary laser displays, with crews on the international space station creating huge beamworks that bug-eyed passengers on the U.S. space shuttle Enterprise could fly through while listening to the latest reissue of the theme music from 2001. But space is a vacuum, and light as well as sound is doomed there. To be sure, doomed is too strong a word. Light is reflected off asteroids, planets and floating pieces of scrap metal from the Mir space station just as it reflected off objects here on Earth. What you won't see in space is what movie producers want you to see---blazing shafts of photons sizzling out from the Starship Enterprise.

To see that spectacle, you have to come down to Earth and buy a ticket to a really good laser show. Which brings me to the topic I'm supposed to be dealing with: what are the key ingredients of a really good outdoor laser show? Summer will be on us before we know it, and along with the latest Star Trek movie, it will be time for outdoor fairs, festivals and concerts. And along with those events will be producers who want to add eye-popping lasers but aren't quite sure how to go about doing it.

The first thing to remember when planning for such a show is a simple tried-and-true maxim: In space, no one can see laser beam shows!

For great looking beam shows on planet Earth, you need the magic ingredient that you don't find in outer space: stuff in the air. Earth's air sometimes has so much stuff in it that laser beams light up like floating neon rods. But the very same laser beam that travels for miles in the 95-percent humidity of a smog-filled summer night in Washington, DC won't look nearly as good in the cold, clear, dry air of a Canadian winter. When you "see" a laser beam in mid-air you are not actually seeing the laser beam-you are seeing the tiny particles in the air that are illuminated by the laser beam.

The tiny particles include dust, water vapor, pollen, smog and who-knows-what-else that we inhale every time we breathe. Which, of course, brings us back to our dreaded tag line, which I am trying to avoid repeating because the astute reader has by now grasped the point that because there is no stuff in the air in space (or air, for that matter) no one can see laser beam shows there (cue off-screen female scream).

When planning a large outdoor laser show for a theme park, sports stadium or city-sized celebration, show producers need to plan early for the "stuff" factor. In many cases, it's possible to use outdoor fogging systems to enhance the laser effects. But if foggers are not practical (or if the display spans several miles and it's impractical to fog such a huge area) then laser companies must pick a light source with so much power that it would be visible in a crystal-clear arctic night.

Such a laser is a 40-watt YAG that produces a lime-green beam. I saw my first YAG display in Las Vegas in the early 90's, and the beam was visible from miles away. Even traveling in my car on the interstate outside of town, the beam was big and bright and beckoning. While a 40-watt YAG is undeniably bright, it's not right for every venue. Perhaps the electrical and water connections are not available for the YAG or the producers want a full-color beam show that can't be created by a green-only YAG. If a more conventional argon or full-color argon-krypton laser is used, the power output (and visibility) drops considerably.

When a show calls for full-color effects, it's time to add stuff to the air and boost beam visibility. With enough airborne haze, relatively low-power lasers can look like Star Trek weapons set on psychedelic. Laser companies have developed their own approaches for this, often relying on a mix of theatrical foggers and custom blowers to disperse the haze. These systems can work in conventional venues (think of huge outdoor sports stadiums) and in truly unusual settings, such as when one laser company set up six floating rafts armed with fogger/blowers to make sure a laser show over a lake would be seen in the proper light.

Although it takes a skilled crew to setup and operate a venue-wide haze system, the advantages are worth it. It allows producers to use a full-color laser (or lower-powered YAGs that don't gobble electricity and water) and to create a wider array of atmospheric laser effects. The mid-air mist created by foggers means that audiences can see cones, tunnels, sheets and fans of light. Imagine a floating pane of light with glittering currents of electrified mist suspended in the air, and you'll start to get the picture. A good laserist incorporates these and other effects in the beam show, so that the laser becomes more than just a souped-up searchlight, but a true mind-opening effect that makes audiences true believers in the power of laser light.

In fact, true believers have probably already realized that the tag line for this piece (which I shall not repeat) is actually … not true (cue off-screen female scream).

In the heavens, just as on Earth, talented laserists will likely find a way to make the show go on. I can picture engineers already at work, developing the precise formula for a zero-gravity micro-particle dispersion system, one that would provide just enough "stuff" in the vacuum of outer space to make laser beams visible. I envision a zero-drift particulate pattern in permanent orbit over North America, so that once the haze is put in place (over the area of, say, a few hundred square kilometers) it stays in place … forever. When the signal is given, audiences on earth will switch their headsets on, cue up the latest bootleg recording of Dark Star, and look to the skies for a truly cosmic laser light show.

But until then, remember: In space no one …