The Total Irradiance Monitor (TIM) is an electrical substitution radiometer (ESR) that measures total solar irradiance (TSI) with extreme accuracy and precision. It has four identical radiometers to provide redundancy and to detect changes in the instrument performance due to exposure to solar radiation. As illustrated by this animation, the TIM is mounted on a two-axis, gimbaled platform that tracks the Sun independent of spacecraft orientation. The Glory TIM will continue the TSI measurements currently being acquired by the TIM instrument on the NASA SORCE satellite, in orbit since 2003.
GCMD keywords can be found on the Internet with the following citation:
Olsen, L.M., G. Major, K. Shein, J. Scialdone, S. Ritz, T. Stevens, M. Morahan, A. Aleman, R. Vogel, S. Leicester, H. Weir, M. Meaux, S. Grebas, C.Solomon, M. Holland, T. Northcutt, R. A. Restrepo, R. Bilodeau, 2013. NASA/Global Change Master Directory (GCMD) Earth Science Keywords. Version 188.8.131.52.0