The Lockheed Martin-led team developing the Orion crew exploration vehicle has completed fabrication of what it claims is the world’s largest heat shield structure. The shield, which is 5 m (16.4 ft) in diameter, protects the spacecraft and its crew from extreme temperatures during re-entry.
The work was completed at Lockheed Martin’s composite development facility in Denver.
Among several new technologies and innovations spawned from the development of the spacecraft is a “cutting-edge” high-temperature composite material system. The new system was developed by the Lockheed Martin Orion thermal protection system team in partnership with TenCate Advanced Composites, a supplier of aerospace thermoset and thermoplastic prepregs.
The new resin system was developed over an 18-month period during which thousands of coupons were tested in extreme environments that simulated a ballistic re-entry from a lunar mission. The team verified that the thermal insulator on the outside of the composite material can be thinner due to higher temperature capability, resulting in improved mass optimization.
“Its usage temperature is significantly higher than standard composites; this is a new technological breakthrough for out-of-autoclave composites,” Colin Sipe, Orion Ground Test Article Thermal Protection System Design Lead, told Aerospace Engineering & Manufacturing in an e-mail.
Specific temperature data for the new material cannot be released publicly, a company spokesperson said. But standard composites can withstand temperatures of about 200-300ºF. “The high-temperature materials we have developed through this new composite system significantly improves that temperature threshold,” Sipe added.
Does this higher temperature performance come at a higher price? Not necessarily. “The cost is about the same as a standard aerospace composite,” he claims.
The new material also enables simpler and more efficient manufacturing techniques compared to other high-temperature resin systems. “A large autoclave is not required to fabricate the hardware, only an oven,” Sipe explained. “Therefore, it takes less investment in facilities, and it allows for less manufacturing time.”
The technology has the potential to be used in a range of commercial applications, including aircraft, automobiles and heavy vehicles, launch vehicles, payload fairings, and re-entry vehicles.
“The family of high-temp composite material systems is available now from TenCate. It has many uses; it’s really limited to the designers’ imagination,” Sipe said regarding possible commercial applications. “But anywhere on a vehicle there are high-temperature locations—near engines, inlets, exhaust, main structure, etc.”—is particularly well-suited to the material.
“In addition to the technology advancement, we achieved a $10 million cost savings and improved the project schedule by 12 months through the innovative tooling, materials, and fabrication processes the team put into action,” explained Cleon Lacefield, Lockheed Martin Vice President and Orion Program Manager.
The heat shield will be finished in the fall of 2010, according to Sipe, which includes a static load proof test. It then will be applied to the Orion ground test article (GTA), which is the first full-sized, flight-like test article for Orion being built at the Michoud Assembly Facility in New Orleans, LA.
Designed to validate the flight-vehicle production processes and tools, the GTA will be tested in the winter of 2010 to the spring of 2011, Sipe said. When completed, the crew module will be tested on the ground in equivalent flight-like environments, including static vibration, acoustics, and water landing loads.
Lockheed Martin, the prime contractor to NASA for the Orion, stresses that this early high-fidelity testing is necessary to correlate sizing models for all subsystems on the vehicle.
The Lockheed Martin Orion Project office is based in Houston near NASA’s Johnson Space Center. The team includes major subcontractors Aerojet, Alliant Techsystems (ATK), Hamilton Sundstrand, Honeywell, Orbital Sciences Corp., and United Space Alliance. Also part of the team are minor subcontractors and small businesses working at 88 facilities in 28 states across the U.S.