The Shuttle Solar Backscatter Ultraviolet Spectrometer (SSBUV) has been calibrated for its first Shuttle flight, currently scheduled for Autumn, 1989. The purpose of the SSBUV instrument is to provide regular in-orbit calibration checks of the SBUV/2 ozone monitoring instruments being flown routinely on NOAA satellites. The in-orbit calibration transfer will be accomplished by comparing the observations of the Shuttle and satellite instruments. The observables are the solar irradiance and the backscattered terrestrial radiance in the wavelength region between 252 and 340 nm. The Shuttle instrument is carefully calibrated before and after each flight. The long-term ozone monitoring program requires reduction of uncharacterized drifts in the satellite instruments to a value less than the expected ozone trend at the 95% confidence level. This translates to a requirement that the SSBUV be calibrated to a one sigma precision of 1% from one flight to the next. A detailed SSBUV calibration plan establishes procedures for meeting this requirement. Radiometric standards provided by the National Institute for Standards and Technology (NISI) are utilized to determine instrument response and stability. A hierarchy of standards is employed to provide redundancy and minimize biases. Laboratory calibration fixtures were designed to minimize set-up induced systematic errors. Calibration procedures and results are discussed. The initial tests on the accuracy and precision of the wavelength calibration, radiometric linearity, and irradiance and radiance response suggest that the 1% calibration precision requirement can be achieved.

Date Published: 26 September 1989
PDF: 15 pages
Proc. SPIE 1109, Optical Radiation Measurements II, (26 September 1989);

Published in SPIE Proceedings Vol. 1109:
Optical Radiation Measurements II
James M. Palmer, Editor(s)