Results of the 1970 balloon flight solar cell standardization program

For the eighth consective year, high-altitude calibration of solar cells was accomplished with the aid of free-flight balloons. Flights were conducted to an altitude of 36,576 m which is above 99.5% of earth's atmosphere where all water vapor levels and significant ozone bands are absent. Solar cells calibrated in this manner are significant used as intensity references in solar simulators and in terrestrial sunlight. Discussed is the method employed for high altitude balloon flight solar cell calibration. Also presented are data collected on 52 standard solar cells on two flights conducted in 1970. Solar cells flown repeatedly on successive flights have shown correlation of better than + or - 1.0%.