Total and Spectral Solar Irradiance Sensor 2

Enhancing the legacy of solar radiation measurements

Artist's drawing of the TSIS-2 instrument

The Total and Spectral Solar Irradiance Sensor–2 (TSIS-2) is a follow on mission to TSIS-1 to continue to monitor the Earth’s solar energy input-a measurement of the Sun’s brightness at the top of Earth’s atmosphere. TSIS-2 includes two instruments – the Total Irradiance Monitor (TIM) and the Spectral Irradiance Monitor (SIM), which are nearly identical to the instruments on TSIS-1. TIM will continue to provide a 40-year uninterrupted measurement record of the Total Solar Irradiance (TSI) which is the Earth’s predominant energy source. The SIM will continue to measure the Solar Spectral Irradiance (SSI) and identify the regions in Earth’s atmosphere and surface that are affected by solar variability. TSIS-2 will ride on a free-flying spacecraft, unlike its predecessor TSIS-1 which operates from the International Space Station.

Mission Class:

Larger Missions

Mission Status:


LASP Roles:

Research, Instruments, Data, Mission Operations

Science Target:


Mission Focus:

Climate, Earth's Atmosphere, Solar Irradiance
Artist's drawing of the TSIS-2 instrument

Launch Date: 2025

Lead Institution: NASA Goddard Space Flight Center

Lead Funding Agency: NASA Earth Systematic Missions program

Partners: General Atomics Electromagnetic Systems Group