Dr. Chia-Chun (George) Chao has fifty years of experience in astrodynamics covering mission design and analysis, orbit perturbations, stationkeeping and formationkeeping strategies, orbit determination, and atmospheric refraction calibrations. He developed the “Chao model” of troposphere calibration while working at JPL. He is a retired casual engineer with The Aerospace Corporation, as well as an associate fellow of AIAA. He has two U.S. patents in formationkeeping methods.