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Automated model-free anomaly and fault detection using large collections of sensor suites is vital to increasing safety and reducing maintenance costs of complex aerospace systems, such as the space shuttle main engine. Current anomaly and fault detection methods are deficient in that they either require a huge amounts of laborious expert analysis or rely on models that fail to capture unmodelled...
The objective of this research is to find a near optimal control strategy of an electric propulsion space vehicle to consume minimal fuel while traversing between two points in space. Micro genetic algorithms (GA) with the concept of Elitism is used to determine this optimal control
This paper compares the performance of two different launch systems; one with a hydrogen fuelled scramjet stage and one with a hydrocarbon fuelled scramjet stage. The two launch systems are optimized with respect to payload delivery capability and then compared, assuming a fixed launch mass. A rocket powered booster is used to achieve the required scramjet ignition conditions and a rocket powered...
A fundamental problem in the development and validation of PHM technologies is the general shortage of realistic fault signature data. While healthy signatures can be obtained from operational systems, faults are relatively rare and difficult to observe. The PHM community must rely primarily on bench level seeded fault test data collected under a limited set of conditions. To augment physical data,...
Diagnostic technologies for rolling element bearings are relatively well developed, but accurate prediction of remaining life once an incipient fault has been detected is considerably more difficult. This paper describes a comprehensive experimental study of bearing spall progression and a physics-based model being developed for bearing prognostics. The model computes the spall growth trajectory and...
New mission concepts are increasingly considering the use of ion propulsion for fuel-efficient navigation in deep space. The development of new low-thrust mission concepts requires efficient methods to rapidly determine feasibility and thoroughly explore trade spaces. This paper presents parallel, evolutionary computing methods to assess a trade-off between delivered payload mass and required flight...
The F-35 Joint Strike Fighter (JSF) prognostics and health management (PHM) program is redefining the baseline for aircraft PHM. The objective is a management system that enables the F-35 aircraft to identify and report its own maintenance requirements, maximising aircraft use and minimising logistical overhead. JSF PHM offers aircraft operational cost and safety benefits above and beyond any air-vehicle...
NASA's Prometheus project was authorized to develop a revolutionary solar system exploration capability - a nuclear electric propulsion spacecraft $that would, during its initial flight, orbit three icy moons of Jupiter. An innovative acquisition strategy - including competitive industry studies, parallel government studies, customized rules of engagement, research, and benchmarking - was employed...
Temperature and radiation tolerant electronics, as well as long life survivability are key capabilities required for future NASA missions. Current approaches to electronics for extreme environments focus on component level robustness and hardening. Compensation techniques such as bias cancellation circuitry have also been employed. However, current technology can only ensure very limited lifetime...
Space missions often require radiation and extreme-temperature hardened electronics to survive the harsh environments beyond Earth's atmosphere. Traditional approaches to preserve electronics incorporate shielding, insulation and redundancy at the expense of power and weight. However, a novel way of bypassing these problems is the concept of evolutionary hardware. Are configurable device, consisting...
Digital propulsion controls provide the foundation for adding capabilities beyond normal control functions to enable the next level of increased survivability for both war-time and peace-time damage scenarios. Propulsion is a critical system for any platform, providing electrical and hydraulic power, ECS (environmental control system) air as well as thrust. If the vulnerability of propulsion systems...
Propellant will be more than 85% of the mass that needs to be lofted into low Earth orbit (LEO) in the planned program of exploration of the Moon, Mars, and beyond. This paper describes a possible means for launching thousands of tons of propellant per year into LEO at a cost 15 to 30 times less than the current launch cost per kilogram. The basic idea is to mass-produce very simple, small and relatively...
Orbital pushing is going to be an important task to plan, due to the increase of shared or piggyback launches that imply the release of small satellites in orbits different from the final one. Due to launch failures or to changes in the services to supply while operating, orbital reconfigurations could be considered an added value if they can be performed avoiding a considerable consumption of fuel...
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