Turning night into day

February 01, 1993

In the lingo of movie buffs, "day for night" means shooting a scene in daylight, then altering the film so the finished product looks as if it happened at night. It's a Hollywood "special effect" that saves money and time, and by now it has become so familiar viewers don't even pause to wonder how those fabulous "night" scenes were actually made.

But now Russian space scientists hope to go Hollywood one better and literally turn night into "day" -- or at least twilight -- by using a giant orbiting mirror to reflect sunlight down onto the hemisphere of the Earth that normally is dark as the planet spins on its axis.

The project uses a 65-foot-diameter aluminum-coated plastic disc aboard a Progress spacecraft attached to the Mir space station. The disc would peer over the curvature of the Earth to capture the sun's rays and beam them down as spots of reflected sunlight up to 55 miles across. Points on the ground would be illuminated with light equivalent to that of several full moons.

The experiment, if successful, could have important practical applications, from saving billions of dollars a year in electrical lighting costs to extending twilight hours during planting and harvesting seasons and allowing more working hours on large construction projects. It could also help in rescue and recovery operations after natural disasters like earthquakes and hurricanes.

American scientists are keeping close tabs on how the Russian "day for night" effort works out. So should the Pentagon, since the technology may have potential military use. It could deprive enemy forces of the ability to move troops or weapons under cover of darkness, for example. Such a capability might have helped prevent Iraq's night-time Scud missile attack during the gulf war.

Russia may be financially strapped, but this project shows there's no shortage of imagination among its scientists and engineers. One intriguing possibility the Russians hope to explore is the handling of large pieces of plastic in space as a prelude to making giant "sails" to catch the solar "wind" of charged particles flowing from the sun in order to propel spacecraft on long voyages. If all this sounds like something out of a science-fiction novel, well, Hollywood will probably make a movie out of it eventually -- complete with great special effects.

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