An in-flight technique for wind measurement in support of the space shuttle program

Abstract A technique to use an aircraft to measure wind profiles inthe altitude range of 1,500 to 18,200 m has been demon-strated at NASA Ames-Dryden Flight Research Facility.This demonstration was initiated at the request of NASAJohnson Space Center to determine if an aircraft could mea-sure wind profiles in support of space shuttle launches. TheJimsphere balloon is currently the device used to measurepre-launch wind profiles for the space shuttle. However,it takes approximately an hour for the Jimsphere to travelthrough the altitudes of interest. If these wind measurementscould be taken with an aircraft closer to launch in a moretimely manner and with the same accuracy as a Jimsphereballoon, some uncertainties in the measurements could beremoved. The aircraft used for this investigation was anF-104G which is capable of flight above 18,000 m. Ithad conventional research instrumentation to provide air-data and flow angles along with a ring laser gyro inertial nav-igation system (INS) to provide inertial and Euler angle data.During the course of 17 flights, wind profiles were measuredin 21 climbs and 18 descents. Preliminary comparisons be-tween aircraft measured wind profiles and Jimsphere mea-sured profiles show reasonable agreement (within 3 m/sec).Most large differences between the profiles can usually beexplained by large spatial or time differences between theJimsphere and aircraft measurements, the fact that the air-craft is not in a wings-level attitude, or INS shifts caused byaircraft maneuvering.AICSEAFBFPS