The TSIS-1 mission will provide absolute measurements of the total solar irradiance (TSI) and spectral solar irradiance (SSI), important for accurate scientific models of climate change and solar variability. TSIS is comprised of two instruments, the Total Irradiance Monitor (TIM), and the Spectral Irradiance Monitor (SIM). Both instruments are in storage at the University of Colorado’s Laboratory for Atmospheric and Space Physics awaiting flight. Currently, the data from an earlier NASA-managed TIM instrument, flying on the aging SORCE spacecraft, launched in 2003, provides the TSI data record as part of an unbroken 35-year long data record. The Total Solar Irradiance Calibration Transfer Experiment (TCTE) instrument, a joint mission with NOAA and the U.S. Air Force, launched in 2013 and currently augments the data record. The TSIS-1 project will begin formulation in FY 2016 and is planning for launch in time to overlap with the TCTE mission in order to maintain continuity of the solar irradiance measurement. NASA intends to fly TSIS-1 on the International Space Station by 2018.
Total Solar Irradiance (TSI) Spectral Solar Irradiance (SSI)