The ogive fairing is a large curved structure – positioned below the Fillet and encapsulating the crew module – that shields the crew module from high shear and wind loads and, if necessary, from the launch abort motors. Nearly 30 feet in diameter, the ogive fairing is fabricated in four core panels measuring approximately 15 feet across and about 16 feet long.
To accommodate hand lay up of both the Fillet and ogive fairing, SDC built systems to bridge people over the molds and allow them to lay down the prepregs. “It sounds simple,” explains Kolozs, “but when you talk about getting out in the middle of something 8 feet in and 16 feet across and getting good compaction – and you want to lay down a certain amount of material per hour – it’s not.” SDC developed specialized tooling and used a laser projection system to help lay up both parts, which were then cured in the company’s new 16-foot diameter, 30-foot long high-pressure autoclave.
Like the Fillet, the ogive fairing is made of a high-strength carbon fiber/epoxy material, but with a thicker honeycomb core to accommodate a higher load profile. The ogive fairing tapers to a solid laminate at the edges and has syntactic foam placed in high shear load areas as well as foaming adhesive between the core segments. “Lockheed Martin has designed a structure that is best-in-class right now in terms of specific strength and specific stiffness,” Mercer states.
SDC also helped develop a process to infuse NASA’s 3-D Multifunctional Ablative Thermal Protection System (3D-MAT), a new 3-D stitched quartz fiber preform material. After developing the intricate weaving process with Bally Ribbon Mills, NASA discovered that infusion of the dry preform was a challenge. After NASA and several subcontractors struggled to infuse 3D-MAT, they brought the project to SDC. Like others, SDC initially tried to infuse the material using a traditional VARTM process and failed. Mercer says that 3D-MAT’s irregular and non-repeatable shape, as well as its thickness and stitch density, make managing resin flow using traditional VARTM impossible.
So SDC created a process that uses microcontrollers and data recording to control vacuum level, flow path and pressure throughout infusion. “That’s what makes this a really unique process,” says Mercer. “We’re controlling three of these things to a very fine degree in this part, whereas normally you might only control one or two of them. And we’re staging them at times to make sure that we avoid creating voids.”
SDC has since infused 32 billets of 3D-MAT material that will be used to make compression pads and other components for Orion’s next test flight, Exploration Mission 1 (EM-1) in 2018. Last fall, SDC received a special commendation from NASA for its contributions to the development of the 3D-MAT material.
Kolozs says that all of the company’s engineers have worked on Orion at some point. “We’ve grown a lot with the program,” Kolozs reflects, adding that he hopes SDC can remain an Orion partner all the way through its ultimate mission – the journey to Mars. That would be quite a journey for San Diego Composites, too.
