The long-term balance between earth s absorption of solar radiative energy and emission of radiation to space is a fundamental climate measurement required in the NRC s decadal survey report earth…

The Regents of the University of Colorado received a $5.97 million research grant from a federal civilian agency awarded on September 17, 2018, with an ultimate completion date of December 31, 2024. The contract supports the development and demonstration of the Compact Total Irradiance Monitor (CTIM), a next-generation instrument designed to measure total solar irradiance (TSI) from a 6U CubeSat platform. This initiative addresses a critical climate measurement requirement identified in the National Research Council's Decadal Survey on Earth Science and Applications from Space, building upon 40 years of uninterrupted TSI measurements from space. The CTIM utilizes innovative silicon-based vertically aligned carbon nanotube bolometer technology to achieve the measurement accuracy of previous-generation instruments while maintaining the compact form factor and reduced cost and fabrication time necessary for CubeSat deployment.

The performance of work is located in Boulder, Colorado, and encompasses rebuilding key instrument elements based on lessons learned from prior testing, integrating a Blue Canyon Technologies XB1 CubeSat bus, and conducting comprehensive environmental and performance testing. The integrated CTIM Flight Demonstration (CTIM-FD) system targeted launch in September 2020 for a planned one-year on-orbit mission to validate measurement performance against the Total and Spectral Solar Irradiance Sensor operating on the International Space Station. This program aims to raise the technology readiness level of next-generation TSI measurement capabilities, reduce future data gaps, and increase flight opportunities through a more affordable and accessible measurement platform. No set-aside designation was used in this award.

The long-term balance between earth s absorption of solar radiative energy and emission of radiation to space is a fundamental climate measurement required in the NRC s decadal survey report earth science and applications from space: national imperatives for the next decade and beyond. Total solar irradiance (TSI) has been measured from space by a 40-year uninterrupted sequence of instruments. We propose to build and fly a next-generation TSI instrument on a 6U cubesat, the compact total irradiance monitor (ctim). This instrument will meet the measurement requirements of the previous generation instruments while being compact enough to fit on cubesat platform. In order to accomplish this the ctim will utilize new technologies, including silicon-based vertically aligned carbon nanotube (vacnt) bolometers. The goal of this program is to demonstrate and raise the TRL of next-generation technology which will permit the measurement of TSI from a cubesat platform. This compact, lower-mass instrument has shorter fabrication times and lower costs which should provide more flight opportunities, helping reduce the risk of future TSI-measurement data gaps. This program will run from september 17, 2018 through september 17, 2021. We will first rebuild key elements of the ctim instrument developed during the ctim instrument incubator program (IIP) program, incorporating lesson learned from the environmental and performance testing of the ctim. We will then procure and integrate a blue canyon technologies XB1 cubesat bus. The integrated system will undergo environmental, performance, and end-to-end testing. The target launch date of the ctim-FD is september 2020. The planned one-year mission will test the on-orbit performance of the ctim-FD directly against total and spectral solar irradiance sensor (tsis) total irradiance monitor (TIM) currently operating on the international space station. During this measurement we will test the initial measurement accuracy of the ctim, and the long-term stability of the measurements over the mission life. The ctim entry TRL is 5, based on prototype testing work performed on the carbon absolute electrical substitution radiometers (caesr) advanced component technologies (act) project and the related compact spectral irradiance monitor (csim) IIP project. The planned exit TRL is 7-9 based on successful on-orbit operations.