Analyses of Kennedy Space Center Tropospheric Doppler Radar Wind Profiler Data for Space Launch System Program Certification

This paper documents the methodology and results of analyses used to certify the Kennedy Space Center Tropospheric Doppler Radar Wind Profiler (TDRWP) as input to launch commit evaluations for the National Aeronautics and Space Administration’s Space Launch System Program (SLSP). These analyses, and the requirements that they address, were designed by the Marshall Space Flight Center Natural Environments Branch to certify that the TDRWP provides data of sufficient accuracy and resolution for SLSP, and that the instrument provides enough reliability to support Day-of-Launch (DOL) Initialization Loads Update operations. Requirements consisted of imposing criteria for time interval, vertical data interval, data collection period, wind accuracy, altitude, reliability, and effective vertical resolution (EVR). Examining TDRWP data addressed the time interval, vertical data interval, and data collection criteria. Wind accuracy and altitude were assessed in conjunction by quantifying the altitude range over which the wind accuracy criterion of 1.5 m/s component error was met. This analysis entailed comparing concurrent TDRWP and Automated Meteorological Profiling System balloon profiles while accounting for contributions to the deltas from balloon measurement errors and spatial separation between the TDRWP and balloon. Reliability was assessed by finding the probability of waiting at most five minutes for a usable profile over the data collection period, where usable was defined as a profile that passed a rigorous set of data quality checks similar to those used to develop climatologies from heritage 915-MHz and 50-MHz wind profilers. Planned outages and convective periods were removed from the reliability assessment assuming that SLSP launch vehicles would not launch during said periods. The TDRWP EVR requirement was derived based on the minimum wavelength an instrument would have to resolve to support the planned DOL timeline, and spectral analysis following heritage methodologies implemented on balloon and wind profiler data quantified EVR. Results from these analyses showed that the TDRWP passed all requirements that contained criteria for certification, and thus the instrument can be used as the primary source of wind profiles for use by SLSP on DOL.