First came micromachines--engines about the size of a grain of sand. Now there are microtransmissions. Fabricated by researchers at Sandia National Laboratories, they remarkably augment the power of the tiny engines. Looking through a microscope one would see a spindly, one-millimeter-thick Allen wrench passed over a microtransmission. The sight resembles the huge alien space ship that darkened and then covered New York in the movie "Independence Day." Despite its size, a microtransmission can increase the power of its microengine by a factor of 3 million, theoretically generating enough force to move a one-lb object, says researchers Steve Rodgers and Jeff Sniegowski. The microtransmissions operate on the same principle that allows a multigear bicycle to be pedaled up a steep hill more easily than a single-speed bike: No more input force is used, but a the force is applied over a shorter portion of the wheel's turn. The 3 million:1 Sandia microtransmission comprises six identical transmission systems, each with two dual-level gears. The two gears, crafted one atop the other, operate at ratios of 3:1 and 4:1, which together form a 12:1 gear reduction ratio. A coupling gear allows more gear sets to be added in modules. E-mail Paul McWhorter at [email protected].