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Wireless TPS Sensors. Chris Johnson Jesse Pentzer Brandy Holmes John Sochacki Lucus Wells. Outline. Background Needs/Specs Designs Design 1 Design 2 Design 3 Trade Study Sensors Budget Schedule Challenges Conclusion Acknowledgments. Background.
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Wireless TPS Sensors Chris Johnson Jesse Pentzer Brandy Holmes John Sochacki Lucus Wells
Outline • Background • Needs/Specs • Designs • Design 1 • Design 2 • Design 3 • Trade Study • Sensors • Budget • Schedule • Challenges • Conclusion • Acknowledgments
Background • The re-entry environment is extremely difficult to model. • NASA Ames desires a wireless sensor system that can be integrated into the Thermal Protection System (TPS) of entry vehicles. • Complications with adding extra wiring and the risk involved in adding sensors to the mission. • A wireless sensor system would remove wiring complexities, reduce mass, and reduce risk associated with cable cutting. • With a greater understanding of the environment encountered during atmospheric re-entry the TPS of future missions could be made safer and more efficient.
Sensors • Omega Type K Thermocouples with Glass Braid Insulation • Range: -270 to 1372 °C • Uncertainty: Greater of 2.2 °C or 0.75% • Cost: $33 for five thermocouples with one meter leads • Honeywell ASDX-DO Series Pressure Sensors • Range: 0 to 30 psi absolute • Uncertainty: 2.0% Full Scale • Temperature Range: -20 to 105 °C • Cost: $33.27 Each • Omega Thin Film Resistance Thermal Detectors • Range: -70 to 500 °C • Uncertainty: Dependent on Calibration Equation • Cost: $47.50 for pack of five
Budget • Common Cost to all designs:$679.16 • Design One • 9 PCB’s • 9 Batteries • 9 X-Bee chips • Total Cost: $1333.91 • Design Two • 11 PCB’s • 3 Batteries • 3 X-Bee’s • Total Cost: $1137.41 • Design Three • 11 PCB’s • 5 Batteries • 5 X-Bee’s • Total Cost: $1222.91 • Thermal Exposure’s Budget: $2240
Challenges • Code Complexity • RF Opaque Materials • Design Packaging for Harsh Landing Conditions • Thermal Protection of Circuit
Conclusions • Thermal Exposure’s Favorite? • Design One!!! • Why? • Versatility • Simplicity of Code • Simplicity of Design • Small Size and Weight
Acknowledgments • Faculty Advisors • David Atkinson • Steve Beyerlein • Mentors • Greg Swanson • Tye Reid • Justin Schlee • NASA Ames • David Hash • Johnny Fu • Ed Martinez