Start Date
28-4-1989 2:00 PM
Description
Electromagnetic probing of the atmosphere by clear-air radars is an emerging technology to supplement balloon-borne wind sensors which are used to determine ascent wind loads on the Space Shuttle.
At present, during the Space Shuttle launches, the ascent wind loads are computed 1 hr before launch based on winds aloft obtained by the Jimsphere 3.5 hr before liftoff. There is a need of wind load data acquisition closer to L-0 and in real time for wind loads assessment. The radar technology used in Marshall Space Flight Center's (MSFC) Radar Wind Profiler exactly matches the technology in the Clear-Air Doppler Radars except the frequency is generally lower, antenna is bigger, and dwell time is longer. Its primary work-a-day problem will be to monitor the vertical wind profile prior to launch of the Space Shuttle at more frequent intervals and nearer to launch time than is presently possible with the conventional balloon systems.
The Radar Wind Profiler will obtain a new wind profile on the order of every 15 min based on an average of five wind profiles measured every 3 min at a height interval of 150 m to 10-13 20 km. Additional data obtained in real time, which assists in determining the variability of wind profiles, are a presentation of the spectral moments from the power spectra of the returned signal. However,the winds cannot be substituted directly for Jimsphere winds because the vertical resolution is not as fine as the 100 to 200 m resolution of the Jimsphere.
Paper Session IV-A - Wind Measurements By Electromagnetic Probes
Electromagnetic probing of the atmosphere by clear-air radars is an emerging technology to supplement balloon-borne wind sensors which are used to determine ascent wind loads on the Space Shuttle.
At present, during the Space Shuttle launches, the ascent wind loads are computed 1 hr before launch based on winds aloft obtained by the Jimsphere 3.5 hr before liftoff. There is a need of wind load data acquisition closer to L-0 and in real time for wind loads assessment. The radar technology used in Marshall Space Flight Center's (MSFC) Radar Wind Profiler exactly matches the technology in the Clear-Air Doppler Radars except the frequency is generally lower, antenna is bigger, and dwell time is longer. Its primary work-a-day problem will be to monitor the vertical wind profile prior to launch of the Space Shuttle at more frequent intervals and nearer to launch time than is presently possible with the conventional balloon systems.
The Radar Wind Profiler will obtain a new wind profile on the order of every 15 min based on an average of five wind profiles measured every 3 min at a height interval of 150 m to 10-13 20 km. Additional data obtained in real time, which assists in determining the variability of wind profiles, are a presentation of the spectral moments from the power spectra of the returned signal. However,the winds cannot be substituted directly for Jimsphere winds because the vertical resolution is not as fine as the 100 to 200 m resolution of the Jimsphere.
Comments
Launch Responsiveness
Session Chairman: William S. Files, Deputy Director, Titan IV System Program Office, Deputy
Commander for Launch Systems, Space Division, Los Angeles, CA
Session Organizer: Gary Spirnak, 6555th Aerospace Test Group, Patrick Air Force Base, FL