Dr. Donald Erbschloe, Air Mobility Command chief scientist, and Col. Keith Boone, AMC Fuel Efficiency Division chief, spoke with Tahan Pangaribuan, Solar Impulse flight director assistant yesterday. Solar Impulse is currently hanging out at the Lambert-St. Louis International Airport where it landed June 4. A solar-powered airplane, the project began in 2003 with a 10-year budget of 90 million euros ($112 million). Bertrand Piccard and Andre Borschberg, Swiss pilots and co-founders of the project, take turns flying the plane. It is the first attempt to fly across the United States  using no fuel but the sun’s energy. Developers hope to…