NASA's TSIS-2 sunlight mission clears vacuum and vibration testing ahead of launch

2 November 2026

NASA said its Total and Spectral Solar Irradiance Sensor-2 spacecraft, known as TSIS-2, has passed the tests that clear it for launch.
The spacecraft came through thermal vacuum testing at below-freezing temperatures and vacuum pressures, a mass properties test and vibration testing that simulates the shaking of a launch.
TSIS-2 will measure the intensity of sunlight reaching the top of Earth's atmosphere, both the total amount and how that energy is spread across ultraviolet, visible and near-infrared wavelengths.
It carries two instruments for that work, the Total Irradiance Monitor and the Spectral Irradiance Monitor, both developed by the Laboratory for Atmospheric and Space Physics at the University of Colorado.
General Atomics Electromagnetic Systems built the spacecraft, ran the testing and will operate it in orbit.
Launch is targeted for early 2027 from New Zealand on a Rocket Lab Electron rocket, into low Earth orbit.
The mission continues a record of total solar irradiance that began in 1978 and a record of spectral solar irradiance that began in 2003, and its data are meant to improve climate predictions.