The sidewalk outside Systems Technology, Inc. in Hawthorne, California, feels solid. Or so my senses tell me. Only moments ago, they told me I was plummeting earthward from about 5,000 feet. The skydiving simulator, called PARASIM, takes you from the ground to “Geronimo!” without making you bail out of a perfectly good airplane. “This is not a game,” STI president and CEO Dave Landon says. “This is the only parachute simulator in the U.S. We hold the patent.