8.1 Development of a Climatology of Vertically Complete Wind Profiles from Doppler Radar Wind Profiler Systems

Space vehicle loads and trajectory assessments utilize archives of both discrete and sequential wind profiles to ensure robust structural integrity during vehicle design. Historically, vehicle programs have used balloonbased measurements, which have three primary limitations inherent to balloon systems. First, the high cost of balloon releases makes high-frequency balloon sampling impractical, thereby limiting sample size of archives and thus increasing statistical uncertainty in vehicle ascent analyses. Second, historical vehicle program requirements have influenced the temporal interval of day-of-launch (DOL) balloon measurements, which constrains the intervals that current vehicle programs can assess wind change. Third, balloon measurements could misrepresent the environment through which the vehicle flies due to downrange drift and rise time characteristics. The Marshall Space Flight Center Natural Environments Branch (MSFC NE) developed an archive of quality controlled (QC’ed) wind profiles from Kennedy Space Center’s (KSC’s) 50-MHz Doppler Radar Wind Profiler (DRWP) system (Decker and Barbré 2011, Barbré 2012) to mitigate these shortcomings as the DRWP archive provides orders of magnitude more profiles than balloon archives and allows for wind change assessments over numerous time intervals. In addition, the near-instantaneous and nearvertical sampling of a DRWP profile theoretically represents the wind through a vehicle’s flight path better than a drifting balloon. NASA’s Ares and Space Launch System (SLS) launch vehicle programs have incorporated the DRWP in the early design phase. However, the 50-MHz DRWP archive contains a limitation in that it does not contain data below 2.7 km, which left MSFC NE with the desire to merge the 50-MHz DRWP output with that from other DRWP systems to support any application that may require characterizing wind magnitudes and changes at these low altitudes. MSFC NE develops a technique to generate vertically-complete DRWP wind profiles using the previously-generated 50-MHz DRWP archive (Barbré 2012) and an archive from the 915-MHz DRWP network at the United States Air Force Eastern Range (ER) to provide the capability to assess the wind’s effects on the vehicle at low altitudes. Applications that require knowledge of winds below 2.7 km include liftoff clearance, plume damage, and crew capsule pad abort. MSFC NE leverages on the 915-MHz DRWP systems