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| Integrated Vehicle Health Monitoring HEDS Technology Demonstration 2 |
| Payload Bay |
| 254 lbs. |
| Prime: Rick Husband |
| Overview |
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This is the second of two planned flights of the IVHM HTD, an experiment designed to evaluate the feasibility of using modern commercial sensors to monitor the health of space shuttle systems during flight in order to reduce ground processing of NASA's fleet of orbiters. IVHM HTD-1 was flown on STS-95 in October-November of 1998. Shuttle processing currently involves the verification of thousands of requirements to determine the health of shuttle systems. In early 1997, NASA studied these requirements to determine if it could reduce the processing time and increase vehicle safety. NASA found that ground processing (planned and unplanned) could potentially be reduced 15 to 20%. Planned work could be reduced by implementing a system with predictive capabilities to monitor subsystem health in real time during flight and by extending the service life of life-limited components. Unplanned work could be reduced by improving visibility of system health and streamlining problem isolation. IVHM is essentially an advanced form of a traditional vehicle instrumentation system, which consists of sensors (pressure, temperature, voltage, strain, acceleration, etc.), wiring, signal conditioning devices, multiplexing devices, and recording devices. But an IVHM system goes a step further by providing the capability to process data instead of merely recording data. This allows an onboard trend analysis that could detect system degradation and control in-flight systems checkout in addition to allowing more efficient system servicing and checkout on the ground. During the terminal launch countdown, an IVHM data stream is transmitted to the Launch Control Center for processing and viewing. Approximately 10 seconds before takeoff, the IVHM processor autonomously begins recording data. Data is recorded during ascent and during predefined periods on orbit. The recorded data is dumped to a ground system after the mission. On STS-96, the experiment will be activated during prelaunch cryogenic propellant servicing. The pilot will deactivate the HTD about one hour after launch. The crew will activate the experiment for one hour each day during the mission. The IVHM HTD-2 experiment package consists of an air transport rack for data acquisition and processing and two remote health nodes mounted on a getaway special beam in the orbiter payload bay. The ATR and RHNs are connected by cables to 120 sensors in the orbiter aft crew compartment and payload bay. One of the technologies to be demonstrated is microelectromechanical sensing for detecting the presence of hazardous gas and sensing pressure in vacuum-jacketed lines in the orbiter's cryogenic distribution system. Other technology demonstrations include Bragg-Grating fiber-optic sensing for hazardous gas detection and structural strain/temperature determination, thermal flow meter leak detection, accelerometers for space shuttle main engine pump vibration sensing, VME bus architecture, and flash card memory. The HTDs will also provide data on the performance of commercial computing products, such as a VME bus architecture and ATR chassis, and on the effects of radiation and heat on commercial and military VME hardware. The focus of IVHM HTD-2 is to determine the health of selected functions of the orbiter's main propulsion system, main engines, and power reactant storage and distribution system. The technologies to be developed include Bragg-Grating fiber-optic sensors for hydrogen, strain, and temperature sensing and smart sensors for hydrogen, oxygen, and pressure sensing. IVHM HTD-2 will also evaluate distributed data acquisition by the remote health nodes with fiber data distributed interface communication and a lightweight, low-power microelectronic hardware platform; real-time information processing of space shuttle main engine pump vibration; solid-state data storage; and advanced control room equipment and applications. A complete flight IVHM system consists of advanced lightweight, low-power sensors; distributed data acquisition and processing; real-time information processing, including diagnostics, prognostics, and vehicle autonomy for control or suggested action; and advanced solid-state, high-density data storage. A complete ground IVHM system consists of improved control room architectures and automated ground support equipment. This experiment will advance the development of a subset of a complete IVHM system. |
| History/Background |
| The IVHM HTD experiments are part of NASA's Human Exploration and Development of Space enterprise. HEDS is pursuing answers to myriad research and engineering questions that must be answered as humans learn to live and work in space. The goals of the HEDS enterprise are to explore the solar system, use the environment of space to expand scientific knowledge, provide safe and affordable human access to space, and enrich life on Earth through space. |
| Benefits |
| The IVHM HTDs are providing data on the performance of advanced sensing technologies and commercial products which may be useful in reducing the cost and time associated with processing the space shuttle, streamlining problem troubleshooting, and improving NASA's awareness of shuttle systems during operation. Technologies and products that are found to be useful will be incorporated into an IVHM system for the shuttle. The data from these experiments may also be used to benefit other programs, such as liquid flyback boosters, X vehicles, the crew return vehicle, and lunar/Mars missions. |
Editorial/Technical Comments: ShuttlePresskit
