More than 206 million miles away, solar panels designed by Entech help drive NASA’s Deep Space 1 satellite toward a September 2001 rendezvous with the comet Borrelly. Back on Earth, advances to technology used by the satellite may slash solar power costs dramatically and transform an alternative energy source into common use. Panels built by Keller-based Entech were recently tested by NASA and the U.S. Department of Energy. They set what is believed to be a record for turning sunlight into electricity. “It’s the highest efficiency [ system] we’ve ever measured using lens and cells, 27.6 percent,” said Keith Emery, the engineer who tested the technology at the Department of Energy National Renewable Energy Laboratory in Golden, Colo. “The highest we had seen before was a Boeing system at 25 percent in 1993.”