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CSIM

Compact Spectral Irradiance Monitor

Miniaturizing technology to study spectral irradiance

The Compact Spectral Irradiance Monitor (CSIM) is a 6U CubeSat launched in late 2018 and decommissioned in February 2022. It will demonstrate next-generation technology for monitoring spectral solar irradiance. CSIM is a two-channel 6U CubeSat that includes a miniaturized version of the SIM instrument that flew on both SORCE and TSIS missions. It is designed to measure the solar spectral irradiance twice a day with amazing accuracy. The key detector that enables this level of accuracy, a vertically-aligned carbon nanotube electrical substitution radiometer, was developed jointly with the Sources and Detectors Group at NIST Boulder.

Mission Class:

CubeSats

Mission Status:

Past

LASP Roles:

Research, Instruments, Data, Mission Operations

Science Target:

Sun

Mission Focus:

Climate, Solar Irradiance

Primary Mission Site:

https://lasp.colorado.edu/csim

Launch date: December 3, 2018
End Date: February 2022

Lead Institution: LASP

Lead Funding Agency: NASA

Partners: University of Colorado Boulder, NASA Earth Science Division, NIST Synchrotron Ultraviolet Radiation Facility (SURF), Spaceflight Industries

Radiative energy from the Sun establishes the basic climate state of the Earth’s surface and atmosphere and defines the terrestrial environment that supports all life on the planet. Solar variability occurs on a wide range of scales and affects atmospheric dynamics and chemistry along with photosynthetic processes in the biosphere–driving interactions among the atmosphere, oceans, ice, and land. The continuous measurement of solar spectral irradiance (SSI) is essential to interpreting how the Earth system responds to solar spectral variability and ultimately identifying the physical mechanisms of response. Fundamental objectives related to SSI monitoring extend to a broad science community that includes studies on Earth energy budget, process-oriented remote sensing applications, climate and atmospheric modeling, and atmospheric composition.

The current implementation for continuous SSI monitoring is the Total and Spectral Solar Irradiance Sensor (TSIS-1) Spectral Irradiance Monitor (SIM) that began operations in March 2018. The TSIS-1 SIM – CSIM operational overlap offers SSI measurement advantages that have not been previously exploited. Because of the common, traceable calibration tie between the two instruments, operational overlap allows for a unique cross-calibration opportunity to verify and validate, on-orbit, the absolute accuracy as well as temporal and spectral stability of the CSIM mission concept.