The 1999 solar cell calibration balloon flight campaign consisted of two flights, which occurred on June 14, 1999, and July 6, 1999. All objectives of the flight program were met. Fifty-seven modules were carried to an altitude of approximately equal to 120,000 ft (36.6 km). Full I-V curves were measured on five of these modules, and output at a fixed load was measured on forty-three modules (forty-five cells), with some modules repeated on the second flight. This data was corrected to 28 C and to 1 AU (1.496 x 10 (exp 8) km). The calibrated cells have been returned to their owners and can now be used as reference standards in simulator testing of cells and arrays.Anspaugh, B. E. and Mueller, R. L. and Weiss, R. S.Jet Propulsion LaboratoryBALLOON FLIGHT; CALIBRATING; SOLAR CELLS; MODULES; FABRICATION; LOADS (FORCES); CHECKOUT; DATA PROCESSING; PAYLOADS; DATA ACQUISITION...