Suntracker balloon flights - 3033, 3034, 3035 and 3037 Final report
Preparations, field operations, and instrumentation for suntracker balloon flights
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Preparations, field operations, and instrumentation for suntracker balloon flights
The 1986 solar cell calibration balloon flight was successfully completed on July 15, 1986, meeting all objectives of the program. Thirty modules were carried to an altitude of 118,000 ft (36.0 km). The calibrated cells can now be used as reference standards in simulator testing of cells and arrays.
The Jet Propulsion Laboratory (JPL) solar cell calibration program was conceived to produce reference standards for the purpose of accurately setting solar simulator intensities. The concept was to fly solar cells on a high-altitude balloon, to measure their output at altitudes near 120,000 ft (36.6 km), to recover the cells, and to use them as reference standards. The procedure is simple. The reference cell is placed in the simulator beam, and the beam intensity is adjusted until the reference cell reads the same as it read on the balloon. As long as the reference cell has the same spectral response as the cells or panels to be measured, this is a very accurate method of setting the intensity. But as solar cell technology changes, the spectral response of the solar cells changes also, and reference standards using the new technology must be built and calibrated. Until the summer of 1985, there had always been a question as to how much the atmosphere above the balloon modified the solar spectrum. If the modification was significant, the reference cells might not have the required accuracy. Solar cells made in recent years have increasingly higher blue responses, and if the atmosphere has any effect at all, it would be expected to modify the calibration of these newer blue cells much more so than for cells made in the past. JPL has been flying calibration standards on high-altitude balloons since 1963 and continues to organize a calibration balloon flight at least once a year. The 1995 flight was the 48th flight in this series. The 1995 flight incorporated 46 solar cell modules from 7 different participants. The payload included Si, amorphous Si, GaAs, GaAs/Ge, dual junction cells, top and bottom sections of dual junction cells, and a triple junction cell. A new data acquisition system was built for the balloon flights and flown for the first time on the 1995 flight. This system allows the measurement of current-voltage (I-V) curves for 20 modules in addition to measurement of modules with fixed loads as had been done in the past.
The 1982 solar cell calibration balloon flight was successfully completed on July 21, meeting all objectives of the program. Twenty-eight modules were carried to an altitude of 36.0 kilometers. The calibrated cells can now be used as reference standards in simulator testing of cells and arrays.
The 1983 solar cell calibration balloon flight was successfully completed and met all objectives of the program. Thirty-four modules were carried to an altitude of 36.0 kilometers. The calibrated cells can now be used as reference standards in simulator testing of cells and arrays. Cell calibration data are tabulated as well as the repeatability of standard solar cell BFS-17A (35 flights over a 21-year period).
The 1984 solar cell calibration balloon flight was successfully completed on July 19, meeting all objectives of the program. Thirty-six modules were carried to an altitude of 36.0 kilometers. The calibrated cells can now be used as reference standards in simulator testing of cells and arrays.
The 1985 solar cell calibration balloon flight was successfully completed on July 12, 1985, meeting all objectives of the program. Fifty-seven modules were carried to an altitude of 115,000 ft (35.0 km). The calibrated cells can now be used as reference standards in simulator testing of cells and arrays.
The 1987 solar cell calibration balloon flight was successfully completed on August 23, 1987, meeting all objectives of the program. Forty-eight modules were carried to an altitude of 120,000 ft (36.0 km). The cells calibrated can now be used as reference standards in simulator testing of cells and arrays.
The 1988 solar cell calibration balloon flight was successfully completed on August 7, 1988, meeting all objectives of the program. Forty-eight modules were carried to an altitude of 118,000 ft (36.0 km). The calibrated cells can now be used as reference standards in simulator testing of cells and arrays.
The 1989 solar cell calibration balloon flight was successfully completed on August 9, 1989, meeting all objectives of the program. Forty-two modules were carried to an altitude of 118,000 ft (36.0 km). The calibrated cells can now be used as reference standards in simulator testing of cells and arrays.
The 1990 solar cell calibration balloon flight consisted of two flights, one on July 20, 1990 and the other on September 6, 1990. A malfunction occurred during the first flight, which resulted in a complete loss of data and a free fall of the payload from 120,000 ft. After the tracker was rebuilt, and several solar cell modules were replaced, the payload was reflown. The September flight was successful and met all the objectives of the program. Forty-six modules were carried to an altitude of 118,000 ft (36.0 km). Data telemetered from the modules was corrected to 28 C and to 1 a.u. The calibrated cells have been returned to the participants and can now be used as reference standards in simulator testing of cells and arrays.
The 1991 solar cell calibration balloon flight was completed on August 1, 1991. All objectives of the flight program were met. Thirty-nine modules were carried to an altitude of 119,000 ft. (36.3 km). Data telemetered from the modules were corrected to 28 C and to 1 AU. The calibrated cells have been returned to the participants and can now be used as reference standards in simulator testing of cells and arrays.
Preliminary results of a balloon flight on October 11, 1991, of the solar disk sextant (SDS) experiment are reported. The SDS is an instrument which measures the solar diameter at different orientations with respect to the solar polar axis. Fitting straight lines through two fixed-angle data sets with time as the independent variable yields slopes of (7.1 +/ - 1.5) x 10 exp -3 and (6.7 +/- 1.6) x 10 exp -3/mas s, consistent with the value of 6.47 x 10 exp -3/mas s expected from the earth's approach to the sun due to the orbital motion toward perihelion. Upon the instrument's rotation on its axis a sinusoidal component of the diameter measurement was observed in each rotation cycle, with a variable amplitude of about 150 mas. The present result is epsilon of (5.6 +/- 6.3) x 10 exp -6, about 30 deg offset from the polar-equator position. The absolute diameter obtained by means of the FFT definition is found to be 1919.269 +/- 0.240 arcsec or 1919.131 +/- 0.240 arcsec, depending on the orientation mode of the measurement.
The 1992 solar cell calibration balloon flight was completed on August 1, 1992. All objectives of the flight program were met. Forty-one modules were carried to an altitude of 119,000 ft (36.3 km). Data telemetered from the modules was corrected to 28 C and 1 AU. The calibrated cells have been returned to 39 participants and can now be used as reference standards in simulator testing of cells and arrays.
The 1993 solar cell calibration balloon flight was completed on July 29, 1993. All objectives of the flight program were met. Forty modules were carried to an altitude of 120,000 ft (36.6 km). Data telemetered from the modules was corrected to 28 C and to 1 AU. The calibrated cells have been returned to 8 participants and can now be used as reference standards in simulator testing of cells and arrays.
The 1994 solar cell calibration balloon flight was completed on August 6, 1994. All objectives of the flight program were met. Thirty-seven modules were carried to an altitude of 119,000 ft (36.6 km). Data telemetered from the modules was corrected to 28 C and to 1 AU. The calibrated cells have been returned to the 6 participants and can now be used as reference standards in simulator testing of cells and arrays.
The 1996 solar cell calibration balloon flight campaign was completed with the first flight on June 30, 1996 and a second flight on August 8, 1996. All objectives of the flight program were met. Sixty-four modules were carried to an altitude of 120,000 ft (36.6 km). Full 1-5 curves were measured on 22 of these modules, and output at a fixed load was measured on 42 modules. 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 the participants and can now be used as reference standards in simulator testing of cells and arrays.
The 1997 solar cell calibration balloon flight campaign consisted of three flights, the first flight on June 11, 1997, the second flight on August 2, 1997, and the third flight on August 24, 1997. One flight, flown on August 14, 1997, was terminated early because of a telemetry transmitter failure, and its payload was reflown on the August 24 flight. All objectives of the flight program were met. Ninety-eight modules were carried to an altitude of approximately 120,000 ft (36.6 km). Full I-V curves were measured on 32 of these modules, and output at a fixed load was measured on 66 modules. 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 the participants and can now be used as reference standards in simulator testing of cells and arrays.