December 1999 Meeting

Carbon Fiber Composite Materials for Lightweight Optics and Structures
Dr. Brian Catanzaro
Composite Optics, Inc.

http://www.coi-world.com

The upcoming dinner meeting of the Optical Society of San Diego will feature an on-site talk by Dr. Brian Catanzaro of Composite Optics, Inc. (COI). This presentation will concentrate on the properties of composite materials and examples of hardware fabricated in carbon fiber composite materials. Flight hardware as well as research and development efforts will be discussed. Following the talk, a brief tour of the facilities will be conducted.

Abstract: Lightweight, stiff, dimensionally stable materials are in high demand for optical systems that are deployed in space. Classic materials include Zerodur, ULE, Invar, and titanium. However, carbon fiber composites offer significant advantages over these materials: density, low thermal expansion, high stiffness, manufacturability. As a consequence, composite manufacturers such as Composite Optics, Incorporated (COI) have explored their use as materials for opto-mechanical metering structures, telescope housings, and mirrors. NASA has used this technology on a wide variety of missions including the Hubble Space Telescope, Chandra (AXAF) and Cassini. Recently, these materials have been considered the baseline for such missions as NGST and SIM. For information on the use of composites in optical structures, visit
http://www.coi-world.com
http:// www.ngst.nasa.gov
http://www.ngst.nasa.gov/Hardware/text/optics.html

Speaker: Dr. Brian Catanzaro is the Business Manager for Optics and Semiconductor Products at COI. These products include lightweight mirrors for applications including space telescopes, LIDAR and solar energy collection. The semiconductor products include lightweight, stiff, and dimensionally stable wafer, reticle, and photomask stages. Prior to joining the staff at COI, Catanzaro was a phase mask production manager at Litel Instruments. A long time San Diegan, he left briefly for Caltech, returning to UC San Diego for his Ph. D. ECE.

 

Meeting Review:

Our December meeting consisted of pizza dinner, a presentation, and plant tour of Composite Optics Incorporated (COI) hosted by Dr. Brian Catanzaro. Brian is the Business Manager for Optics and Semiconductor Products at COI and also a member of OSSD. Once again our pizza extravaganza meeting was a big success with over 30 people attending. After we finished the pizza feast, Brian gave an energetic and informative talk on the large diameter, lightweight curved mirror structures produced by COI for space applications. We found that these structures are built from sheets of woven 5um carbon fibers. The sheets are cut to size with a water-jet and then assembled like a balsa-wood airplane to form the large mirror blanks. The resulting structures are extremely light-weight, and have excellent thermal and dimensional stability. The mirror surfaces are formed using an epoxy mold replication process from a glass blank and can be either attached as the rib structures are assembled or molded onto the front surface after it is put together.

Brian went on to discuss how this technology is being applied on two ongoing COI projects. The first was the primary mirror for NASA's NGST (Next Generation Space Telescope). This unit will have an 8 meter diameter segmented primary and be used in the visible to near IR spectrum. It will have a surface figure of lambda/10 with a 2nm RMS. Ion beam figuring is used to obtain the final surface figure. The current phase of the project consists of constructing one of the 3 meter segments that make up the overall 8 meter optic.

The second project discussed is the fabrication of the primary for FIRST (Far-Infrared Sub-millimeter Telescope). This is an f/.5, 3.5 meter diameter segmented optic with a 10um RMS surface figure. COI is currently fabricating one of the 2 meter diameter segments of this primary. Testing of their shape in a zero-g environment is simulated by measuring the surface with a Tyman - Green Interferometer at 120 intervals and averaging the results.

The evening wrapped up with an excellent tour of the NGST segment and the 2meter FIRST blank, hosted Brian and Steve Connell. Thanks to all at COI who helped make this a memorable OSSD tour.