Evaluation of holographic subsurface radar for NDE of space shuttle thermal protection tiles

Abstract

Experiments have been carried out to evaluate holographic subsurface radar (RASCAN) for non-destructive evaluation (NDE) of subnominal bond conditions between the Space Shuttle Thermal Protection System tiles and the aluminum substrate. Initial results have shown detection of small voids and spots of moisture between Space Shuttle thermal protection tiles and underlying aluminum substrate. The characteristic feature of this device is the ability to obtain one-sided radar soundings/images with high sensitivity (detecting of wire of 20 micron and less in diameter), and high resolution (2 cm lateral resolution) in the frequency band of 3.6-4.0 GHz. JPL's advanced high-speed image processing and pattern recognition algorithms can be used to process the data generated by the holographic radar and automatically detect and measure the defects. Combining JPL's technologies with the briefcase size, portable RASCAN system will produce a simple and fully automated scanner capable of inspecting dielectric heat shielding materials or other spacecraft structures for cracks, voids, inclusions, delamination, debonding, etc.. We believe this technology holds promise to significantly enhance the safety of the Space Shuttle and the future CEV and other space exploration missions.

Brain Stroke Detection Based on Microwave Imaging

“…RASCAN 형태의 부표면 홀로그래픽 레이다(subsurface holographic radar)를 사용하여 단일 주파수 신호원을 투사 하여 두 개의 Quadrature 채널로 진폭-위상 홀로그램을 획 득하여 이미지 재형성을 2002년 Chapursky 등이 수학적 으로 모델링하여 실제 측정한 데이터를 사용하여 제시하 였다 [36] . 한편, 2007년에는 Lu 등이 우주선의 열 보호 타 일에 결점이 생긴 것을 RASCAN 부표면 홀로그래픽 레 이다로 탐지하기 위한 알고리즘을 개발하였는데, 3.6～ 4.0 GHz의 마이크로파 신호를 사용하여 결점을 홀로그래 피로 3D 이미지 재형성하는 데 성공하였다 [37] .…”

Использование Методов Голографической Подповерхностной Радиолокации Для Неразрушающего Контроля Диэлектрических Конструкций

“…Большинство сред, исследуемых в подповерхност-ной радиолокации, не удовлетворяют этому требованию. Однако встречаются и исключения из этого правила -композиционные материалы на основе стекло-и квар-цевого волокна [21,22], а также вспененного полиуре-тана [8,23]. Особый интерес к исследованию покрытий из полиуретановой пены возник после катастрофы Space Shuttle Columbia в 2003 г. Этот материал, обладающий уникально низкой теплопроводностью и низким удель-ным весом [23,24], использовался для теплоизоляции внешнего топливного бака с криогенным топливом.…”

Holographic subsurface radar for diagnostics of cryogenic fuel tank thermal insulation of space vehicles

“…Microwave diagnostics using holographic subsurface radars [4,11] could be a good alternative to ultrasonic testing. The basic advantage of microwave diagnostics in comparison with ultrasonic ones is the fundamental difference in physical properties effecting the propagation of electromagnetic versus acoustic waves in heterogeneous media.…”