2004 Award Winners
Government Award Winner
Rocket Motor Joint Construction Including Thermal Barrier
Lead NASA Center:
Glenn Research Center (GRC)
This unique, braided carbon-fiber thermal barrier is designed to withstand the extreme temperature environments in current and future solid rocket motors and other industrial equipment. The new, highly reliable thermal barrier was developed for several critical nozzle joints on the Space Shuttle solid rocket motor. The thermal barrier is a revolutionary development that provides an elegant solution to overcome a vexing problem of protecting temperature sensitive O-rings required to seal 60 atmospheres and over 3,000 °C combustion gases.
The new thermal barrier represents a significant improvement over the current joint-fill approach which, on occasion, allows hot combustion gases to penetrate through to nozzle joint O-rings. In the current design, 1 out of 15 Space Shuttle solid rocket motors experiences hot gas effects on the Joint 6 wiper (sacrificial) O-rings. Also worrisome is the fact that joints have experienced heat effects on materials between the room temperature vulcanized (RTV) rubber and the O-rings, and in two cases O-rings have experienced heat effects. These conditions lead to extensive reviews of the post-flight conditions as part of the effort to monitor flight safety.
This important new technology promotes Shuttle and astronaut safety and enables solid rocket motor joint assembly in one-sixth the time of previous approaches with much higher degrees of reproducibility. Another recent success story further illustrates the impact of the new thermal barrier technology. Lockheed-Martin contracted Aerojet to build the solid rocket motors for the Atlas V Enhanced Expendable Launch Vehicle (EELV).
In the spring of 2002, Aerojet experienced a major failure of their solid rocket motor during a qualification test. In that test, hot combustion gas reached the nozzle-to-case O-rings (prior to the addition of the thermal barriers), causing a major structural failure that resulted in the loss of the nozzle and aft dome sections of the motor. Aerojet undertook an aggressive redesign effort to include the Glenn Research Center (GRC) thermal barriers in the joint design. They performed two successful qualification tests (October and December 2002) in which three Glenn thermal barriers blocked the searing hot 3000+ °C pressurized gases from reaching the temperature sensitive O-rings. These successful qualification tests put the Lockheed-Martin/Aerojet team back on schedule for meeting an aggressive launch schedule.
The GRC thermal barriers have since enabled successful flights on two Atlas V commercial launches. The thermal barrier and nozzle joint construction approach presented is mission-critical to the Atlas V Launch Vehicle.
Commercial Award Winner
RP-46 High Temperature Resin System
Lead NASA Center:
Langley Research Center (LaRC)
LARC RP46 is under evaluation for applications in reusable launch vehicles, space exploration systems, advanced aircraft engine components, and numerous other aerospace and non-aerospace programs. The NASA Exploration Initiative "High temperature composite adhesives for reduced mass aeroshells" Project selected RP-46 over other materials. The project's goal is to incorporate state of the art materials into aeroshells with decreased structural mass and increased payload for exploration activities.
The product is currently used on a commercial aircraft. The technology has been selected for missile radomes and structures via a confidential agreement that precludes revealing their names, but acceptance of the LARC RP46 resin system has been widespread.
LARC RP46 with carbon fiber reinforcement enhances the entire missile structure. Unitech anticipates that significant production quantities of LARC RP46 will be required to fill the demand for the material. Worldwide interest in LARC RP46 continues to expand with sample evaluation programs beginning at Formula One Racing Car manufacturers such as Ferrari, Williams F1, Porsche, and Jaguar.
The aerospace and non-aerospace communities are rapidly moving to implement LARC RP46 as a low-toxicity replacement material for the current state-of-the art, high-temperature resin. Firms such as Boeing, Northrop Grumman, General Electric, Lockheed Martin, United Technologies, and others have all conducted internally funded research and development on the technology.
Above: Powder test (left), fluid test (center) and characterization test (right).