High-altitude airborne LiDAR wind profiler is in final preparations to support NASA hurricane mission.
NASA GSFC and Sigma Space personnel successfully integrated the Tropospheric Wind LiDAR Technology Experiment (TWiLiTE) onboard the Global Hawk at the end of June 2013, at NASA Dryden Flight Research Center (DFRC) in southern California’s Mojave Desert, following a two-year period of design and integration activities at Sigma Space HQ to reconfigure the instrument.
TWILITE is an airborne direct detection Doppler wind LiDAR developed at the NASA Goddard Space Flight Center (GSFC) to profile wind velocities through the full troposphere. TWiLiTE measures wind profiles by transmitting a nanosecond, ultraviolet laser pulse into the atmosphere, collecting the laser light scattered back to the LiDAR by clear air molecules, and measuring the Doppler shifted frequency of the received light, the magnitude of which is proportional to the wind speed of the air.
Originally configured for the ER-2 pressurized Q-bay by GSFC and Sigma Space Corporation engineers, TWiLiTE has demonstrated autonomous operation from altitudes in excess of 70,000 feet. In early 2011, principal investigator Bruce Gentry tasked Sigma Space to reconfigure the TWiLiTE instrument for the Global Hawk zone 25 payload bay in support of NASA’s Hurricane and Severe Storm Sentinel (HS3) mission. HS3 is a five-year mission specifically targeted to enhance our understanding of the processes that underlie hurricane intensity change in the Atlantic Ocean basin.
The request to reconfigure TWiLiTE for HS3 posed several unique technical challenges, including reducing the instrument mechanical envelop to fit within the confined volume of the zone 25 payload bay and upgrading the thermal subsystem to accommodate operation within the unpressurized Global Hawk environment.
Sigma Space provided the mechanical infrastructure required to reconfigure and mount TWiLiTE into the Global Hawk, the thermal hardware required to control instrument operational temperatures in the unpressurized environment at altitudes in excess of 65,000 feet, and the electrical power and software interfaces necessary to communicate with the Global Hawk payload control systems. GSFC and Sigma Space personnel fully reconfigured and integrated the instrument using Sigma Space facilities prior to integration of the sensor onboard the Global Hawk in June.
TWiLiTE is scheduled to return to Sigma Space HQ this summer for final instrument modifications and end-to-end performance verification prior to flight test activities onboard the Global Hawk at DFRC this October 2013 and eventual science operations during the 2014 hurricane season.