KENNEDY SPACE CENTER, FLA. -- After returning from a test flight, pilot Rick Svetkoff climbs out of the cockpit of the Starfighter F-104. The aircraft is taking part in a series of pathfinder test missions from the space shuttle runway. Two flights will generate test data to validate sonic boom assumptions about the potential impacts of suborbital and orbital commercial spaceflight from the facility. NASA is assessing the environmental impact of such flights. Starfighters Inc. of Clearwater, Fla., will perform the flights to help in assessing suborbital space launch trajectories from the runway and paving the way for future commercial space tourism and research flights from the facility.