Polarized Submillimeter Ice-cloud Radiometer (PolSIR) Mission Principal Investigator (PI) and Science Management contract

The purpose of this announcement is to report a contract between the National Aeronautics and Space Administration (NASA) Langley Research Center (LaRC) and Vanderbilt University (VU) for execution of the Polarized Submillimeter Ice-cloud Radiometer (PolSIR) Mission Principal Investigator (PI) and Science Management effort.

The VU proposal was submitted and selected from the NASA Announcement of Opportunity (AO) entitled Third Stand Alone Missions of Opportunity Notice (SALMON-3) Earth Venture Instrument 6 (EVI)-6. The Solicitation number is NNH17ZDA004O-EVI6 and was issued in support of the Earth System Science Pathfinder Program Offices' (ESSPPO). The purpose of the PolSIR Mission is to better characterize and understand the diurnal variability of tropical and sub-tropical ice clouds. PolSIR will provide key observational constraints on ice properties in climate models and enable modelers to develop more accurate cloud parameterizations. These new observations will lead to reduced model uncertainty and increased fidelity of climate forecasts in support of critical decision-making.

The PolSIR mission consists of two 12U CubeSats, each equipped with a cross-track scanning polarized submillimeter radiometer in the spectral range of 325 680 GHz and are proposed to fly in non-sun-synchronous orbits, taking science measurements that enable monthly sampling of the diurnal cycle of ice clouds and their microphysical properties in the tropics and sub-tropics. With its unique focus on ice clouds and their diurnal cycle, PolSIR will address the following science (O1 O3) and applications (A1) objectives:

O1: Constrain the seasonally influenced diurnal cycle amplitude, form, and timing of the ice water path (IWP) and particle diameter in tropical and sub-tropical ice clouds

O2: Determine the diurnal variability of ice clouds in the convective outflow areas and understand relation to deep convection

O3: Determine the relationship between shortwave and longwave radiative fluxes and the diurnal variability of ice clouds

A1: Enable improvement of climate models by providing novel observations of the diurnal cycle of ice clouds, ultimately leading to improved climate modeling skills and increased fidelity of climate forecasts in support of critical decision-making.

PolSIR will be built, tested, developed, and operated by a diverse group of scientists, engineers, remote sensing experts, and climate modelers at a variety of career levels. PolSIR builds on the team's extensive experience in all aspects of Earth observations and climate science, as well as on earlier successful Earth Science Technology Office (ESTO)-funded technology development, in particular the successful spaceflight demonstration of the 883-GHz cloud radiometer for the IceCube CubeSat mission led by the PolSIR Deputy PI at NASA's Goddard Space Flight Center (GSFC). The two CubeSat spacecraft will be built by Blue Canyon Technologies (BCT), a leader in developing reliable turnkey smallsats.

This contract is for the PI effort by VU to lead and support the PolSIR Mission, to collect, analyze, and distribute the science and research, and for the Science Data Processing Center (SDPC). This contract does not include the instrument development or Access to Space (ATS) requirements that were also selected as part of the overall PolSIR Mission.