NASA’s solar-powered Helios experimental aircraft lifted off from a U.S. Navy base on the Hawaiian island of Kauai on Monday, reaching a height of 96,500 feet. The $15 million aircraft failed in its attempt to reach an altitude of 100,000 feet, but it broke a record set by its predecessor, the Pathfinder Plus, for 80,201 feet for solar-powered and propeller-driven aircraft in 1998. “It’s a real milestone of flight,” NASA spokesman Alan Brown said. “It’s a landmark achievement, and especially to do it with a solar aircraft that is nonpolluting. It is a triumph of technology in this area.” The radio-controlled Helios craft, which cruises at speeds of 19 to 25 mph, can reach 103,000 feet under ideal weather conditions, its designers say. It could even be used to fly above Mars, NASA says.