Project Title:
Lightweight, SiC-Ceramic-Foam, Mirror Structures
04.05-0236
912393
Lightweight, SiC-Ceramic-Foam, Mirror Structures
Ultramet
12173 Montague Street
Pacoima
CA
91331
Brian E.
Williams
818-899-0236
LaRC
NAS1-19550
047
04.05-0236
912393
Abstract:
Lightweight, SiC-Ceramic-Foam Mirror Structures
Projected NASA civil and commercial space missions will require power systems capable
of greater versatility and higher power levels than those currently available. Advanced
solar dynamic (ASD) power systems offer the potential for efficient, lightweight,
survivable, relatively compact, long-lived space power systems. The solar concentrator,
a key component of the ASD power system, must be lightweight, dependable, and resistant
to chemical attack. State-of-the-art mirrors for concentrator panels are too heavy
and the surface slope error is too high. In a recently concluded program, the company
has developed a mirror fabrication process in which six inch-diameter optical quartz
(Si02) faceplate mirror surfaces, fabricated by chemical vapor deposition (CVD),
were bonded to lightweight ceramic foams fabricated by chemical vapor infiltration
(CVI). The resulting mirrors were shown to withstand exposure over the temperature
range (from -330 to +250F) without deviating from a surface slope error of 1.0 mrad
over a 72" radius of curvature and a surface roughness of <20.0 A RMS. Phase I will
develop a lightweight SiC mirror structure, composed of a CVI ceramic foam structural
material to which a CVD SiC mirror surface will be deposited. CVD SiC is highly polishable
and has the potential of reducing a real density to <0.20 g/cm2, a 40 percent reduction
from the previous study.
The successful completion of this program will result in a significant advance in
the technology of ultra-lightweight stiff mirror structures. Potential commercial
applications include space optical devices such as telescopes and fast-response laser
pointing mirrors, as well as structural and power system components for the Space
Station.
mirrors, lightweight, silicon carbide (SiC0, solar concentrator, advanced solar dynamic
(ASD), space power systems, foam