Title: CubeSat Mission: Developing Technologies for Measuring Earth's Climate
Presenting Author: William H. Swartz
Organization: Johns Hopkins University Applied Physics Laboratory
Co-Author(s): Steven R. Lorentz, Philip M. Huang, Allan W. Smith, David M. Deglau, Shawn X. Liang, Kathryn M. Marcotte, Edward L. Reynolds, John Carvo, Lars P. Dyrud, Stergios J. Papadakis, Dong Wu, Warren J. Wiscombe

Abstract:
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat mission is a NASA Earth Science Technology Office funded pathfinder for a future constellation to measure the Earth's radiation imbalance. RAVAN uses a small, accurate radiometer that measures top-of-the-atmosphere Earth-leaving fluxes of total and solar-reflected radiation. The radiometer demonstrates two key technologies that enable accurate, absolute Earth radiation measurements in a remarkably small instrument. The first is the use of vertically aligned carbon nanotubes (VACNTs) as the radiometer absorber. VACNT forests are some of the blackest materials known and have an extremely flat spectral response over a wide wavelength range. The second key technology is a gallium fixed-point blackbody calibration source, embedded in RAVAN's sensor head contamination cover, that serves as a stable and repeatable reference to track the long-term degradation of the sensor. Absolute calibration is also maintained by regular solar and deep space views. The RAVAN payload will fly on a 3U CubeSat that combines stellar attitude determination, sub-degree pointing, and both UHF and Globalstar communication. We present the scientific motivation, design and characterization of the payload, integration and testing of the RAVAN spacecraft, and plans for the technology/science mission. Launch is anticipated in 2016. The Earth radiation imbalance is the single-most important quantity for predicting the course of climate change over the next century. RAVAN will help enable the development of an Earth radiation imbalance constellation mission that can provide the measurements needed for superior predictions of future climate change.