Large Diameter Optical Metering Structure

Satellite Imaging Optical Metering Structure

 

Large diameter optical metering structure

Rich Simons, Deep Sky Instruments
Doron Shterman, ImageSat International

Application

Space. A high-resolution optical metering structure for a commercial satellite instrument.

Previous Limiting Technology

Near zero CTE precision optics for space applications have been prohibitively expensive for commercial ventures. Stiffness and CTE requirements mandated use of expensive materials and processes.

Challenge

Our customer had a tight schedule and constrained cost requirements. Some of the materials that would make the program possible did not have processing and structural data. Thermal and moisture stability, as well as specific stiffness, continued to be a concern. We believed we could find solutions with new composite materials being developed to support lower cost solutions.

Solution

Rock West Composites collaborated with a broad base of suppliers and brought our in-depth knowledge of design and manufacturing processes to satisfy historically expensive design risks and help our customer’s engineering team through their analysis processes. For the large diameter tube, we selected a new pitch-based 110msi carbon fiber prepreg with a proven cyanate ester resin made from a lower cost 16K yarn (historically this modulus fiber has used 2k tows) spread to a 0.005” per ply lamina. This kept the cost contained while also meeting CTE and CME requirements. We brought this new material to flight ready status through qual-level acceptance testing on the actual laminates used in the structural details. We also developed a new process for hand wrapping the large tube shape, which was technically challenging due to fiber stiffness.

For the primary support structure, a thick solid laminate, we used off-the-shelf ultra high modulus pitch prepreg from our commercial off-the-shelf material supply. This 12K, 92 msi fiber reinforced epoxy utilizes a space qualified 275F curing epoxy to develop a stout 0.011/ply quasi-isotropic laminate to create a thick and very stiff support structure for the primary optic, which helped to reduce cost and schedule.

Product/Service Areas

Dimensionally Stable Structures, Space and Research, Design and Engineering, Tooling, and Testing.