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The Irradiance Instrument Subsystem (IRIS) on the Airborne-Lunar Spectral Irradiance (Air-LUSI) Instrument



Steven Grantham, Thomas C. Larason, Clarence Zarobila, Stephen Maxwell, John Woodward, Kevin Turpie, S. Andrew Gadsden


The objective of the airborne LUnar Spectral Irradiance (air-LUSI) project is to make low uncertainty, SI-traceable measurements of the lunar spectral irradiance in the visible to near-infrared (VNIR) region from an aircraft above most of the optically absorbing components of the atmosphere. The measurements are made from a NASA ER-2 aircraft, which can fly at altitudes of approximately 20 km above sea level. Air-LUSI measurements, corrected for residual atmospheric attenuation, are designed to provide a matrix of low uncertainty Top-of-the-Atmosphere (TOA) lunar irradiances at known lunar phase and libration angles to be compared and combined with other lunar irradiance data sets to constrain the uncertainties in models of lunar irradiance and reflectance. The measurements are also expected to provide insight into the differences between models and satellite sensor measurements of lunar irradiance. This paper describes the development and characterization of the radiometric component of air-LUSI, the Irradiance Instrument Subsystem (IRIS), prior to flight.
Measurement Science and Technology


optics, lunar spectral irradiance, satellite calibration


Grantham, S. , Larason, T. , Zarobila, C. , Maxwell, S. , Woodward, J. , Turpie, K. and Gadsden, S. (2022), The Irradiance Instrument Subsystem (IRIS) on the Airborne-Lunar Spectral Irradiance (Air-LUSI) Instrument, Measurement Science and Technology, [online],, (Accessed April 22, 2024)
Created March 23, 2022, Updated November 29, 2022