Description: The mission of NASA's ATP is to maintain and advance the testing capabilities of the United States' extensive infrastructure of aerospace research facilities. One key component to these ground based test facilities are the force balances used to measure aerodynamic loads on models undergoing characterization and testing. NASA currently maintains an inventory of balances that were designed for previous model designs and operating ranges that may not be as relevant to current test conditions. Project resources do not always allow a balance to be designed for specific testing applications due to the associated costs and schedule. Luna Innovations is proposing to develop new and innovative force balance technology that will reduce the cost of facility instrumentation and allow for reduced design and instrumentation time, while providing more accurate and reliable results when compared to current balances. This development utilizes proven fiber optic sensor technology that integrates active thermal compensation with a highly accurate, multi-channel sensing network. The versatile operating range of this technology with respect to temperatures and loading conditions, combined with a high channel count data processing system designed by Luna, will provide advanced measurement capabilities for NASA facilities and enable accurate testing of emerging propulsion and transport technologies.

Benefits: While NASA is the leader in fundamental research for advancing aerospace technology within the United States, commercial entities are also working to advance the state-of-the-art in high and low-speed propulsion, flight vehicles, and fundamental aerospace sciences. Key to verification of computer simulations is the ability to cost effectively obtain data under ground based simulated flight conditions. The technology developed during this project will enable commercial air and spacecraft developers to obtain vital data which will improve vehicle design, safety, and efficiency. In addition, the strain gauges and system developed during this program will also be applicable across industry to all harsh-environment applications in which electrical gauges cannot survive. Fiber optic gauges provide a miniature, non-intrusive method of accurately measuring strain and temperature while, as opposed to electrical gauges, are EMI-resistant. Luna expects this system will act as a significant upgrade to existing facilities in which current systems have become obsolete.

The implementation of fiber optic technology into a 6-component force balance will enable improved accuracy in aerodynamic measurements made across NASA facilities under a variety of test conditions at a reduced cost when compared to traditional, electrically instrumented balances. Operating at a reduced cost will allow more extensive testing of design features and system level designs in support of the next generation CEV, Next Generation Air Transportation System (NextGen), and advanced propulsion systems. The reduced machining and instrumentation cost of the balances themselves will also enable individual designs to be completed for specific models at a scale that was previously not feasible due to project resource limitations. The versatile operating ranges of this technology will also reduce the design time as the limits of aerodynamic testing are extended. This technology will demonstrate itself as being vital to increasing the future design and testing capabilities of NASA.