A Kennedy Space Center implementation of IEEE 1451 networked smart sensors and lessons learned

To meet the need for more specific and reliable information from ground support instrumentation systems and future spacecraft sensors and to support intelligent health management systems (IHMS), NASA's Instrumentation Branch and ASRC's Advanced Electronics and Technology Development Laboratory at Kennedy Space Center (KSC) have consulted the IEEE 1451 family of smart-sensor standards to develop smart network elements (SNEs). SNEs provide reliable signal conditioning to raw sensors, complex data processing, and communication capabilities with a light implementation of the IEEE 1451 family of standards. They are capable of assessing the health of the raw sensors and the electronics and the reliability and tolerance of the measurement, and they relay this information to higher-level systems. The KSC SNEs employ a scaled-down version of the IEEE 1451.1 object model for smart sensors. The sensors are capable of publish-subscribe and client-server communication over an Ethernet network using a custom on-the-wire transmission format that is bandwidth-conservative. KSC, together with NASA Stennis Space Center, has also implemented a user-defined transducer electronic data sheet (TEDS) to store health information about the sensor, defined as the health electronic data sheet (HEDS). The KSC SNEs expand upon the IEEE 1451 family of standards to include a well-defined communication protocol for high-level sensor-to-sensor interaction and a HEDS structure for passing relevant health data over the network.