Description: Picometrix's time-domain terahertz (TD-THz) non-destructive evaluation (NDE) technology could be used to inspect space flight structures such as inflatable space habitats, thermal protection systems (TUFI-type tiles, SOFI TPS), for voids, disbonds, and damage such as tearing and micron-meteorite impact. The current instrumentation paradigm is that a multi-purpose TD-THz control unit is used to provide common drive, data acquisition, and analysis functionality to interchangeable sensors and imaging which connect to the control unit with a fiber-optic/electrical umbilical. However, the current COTS control unit is substantially larger and heavier than would be desirable for a space-flight capable unit. In Phase II we will construct a prototype compact TD-THz control unit with a fiber optically coupled remote compact TD-THz reflection tomography sensor based on the Phase I designs. At the end of a successful Phase II, and transitioned into Phase III, we envision that a hand-held A or B-Scan NDE imager could attach to a control unit, sufficiently robust for spaceflight, no larger than a shoebox. In Phase II, it should be possible to reduce the size of the control unit to approximately 1/3 of the current values to, for example, 14 in. X 10 in. X 4 in. and 15 pounds.

Benefits: At the end of a successful Phase II, the goal would be to space qualify the compact control unit design in Phase III so that it could be used for in-orbit inspections of inflatable habitats and thermal protection systems. In addition, THz NDE instrumentation will be valuable in characterizing the aging and durability of aircraft and spacecraft materials and components. Materials include ceramics, foams, Kevlar, Zylon, and other non-conductive polymer matrix composites. Additional NDE applications include inspection of soft shell fan containment, thermal protection systems, and composite overwrap pressure vessels.

Ceramics, foams, and polymer matrix composites are used in automobile and ships and many other consumer and industrial products. A compact TD-THz imaging system could be used inspect automobile dashboards, inspect for delamination of printed circuit boards, inspect of pipe insulation, as well as inspect manufactured parts such as pure plastic and paper products. A compact TD-THz imager benefits homeland security applications under development such as personnel and luggage inspection for concealed weapons and explosives (in luggage, shoes, etc.).