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In the past decade, researchers have studied how to model complex systems for diagnostics using multi- signal digraphs and many algorithms have been proposed to perform inference on this graphical model. Multi-signal dependency model can be applied under a single agent paradigm or a cooperative multi-agent paradigm. Under the multi-agent paradigm, we have developed a distributed diagnosis algorithm...
Traditional engine health management development has focused on major gas turbine engine turbomachinery components, such as disks, blades, and main bearings, because these components are expensive to maintain and their failures frequently have safety implications. However, the majority of the events that compromise mission success and equipment availability in military aircraft arise from the degradation...
This paper presents a Mahalanobis distance and projection pursuit analysis based prognostic and diagnostic approach for early detection of anomalies in electronic products and systems. These have been used to detect deviations in system performance from normal operation, and are efficient at characterizing products with short field histories. A case study is presented to demonstrate that an "abnormal"...
Timely detection and response to catastrophic events during the launch and ascent phase of a launch system is of paramount importance to crew safety. This requires an abort system capable of detecting and confirming conditions that may lead to catastrophic failure, notifying the crew of the problem, and responding in time to allow the crew to escape safely. The development process for an Abort Failure...
We report on estimating probability of failure (PoF) of an FA/18 bulkhead based on empirically obtained and published in open literature fatigue-crack growth and equivalent pre-crack size (EPS) distribution data. We demonstrate that the tail of the EPS distribution has a significant effect on PoF. Considering each flight to be a successful (i.e., no failure) fatigue test, we use a Bayesian approach...
The Department of Defense-directed and National Security Agency-led Cryptographic Modernization Initiative (CMI) mandates the use of space- borne reprogrammable cryptographic devices for future satellite systems. This cryptographic paradigm shift has revealed a void in the knowledge base currently used for implementation of cryptographic space products, because reprogrammability has not been addressed...
Many software systems are evolving complex system of systems (SoS) for which inter-system communication is both mission-critical and error-prone. Such communication problems ideally would be detected before deployment. In a NASA-supported Software Assurance Research Program (SARP) project, we are researching a new approach addressing such problems. In this paper, we show that problems in the communication...
Model Driven Development (MDD) is rapidly becoming a mainstream practice for the development of complex aerospace systems. UML has emerged as the de facto standard for modeling languages, supporting a wide range of modeling aspects and refinement levels. As a consequence, models can easily become too complex for manual verification and simple static analysis.
Cooperative control of multiple unmanned vehicles is an attractive and challenging problem which has drawn considerable attention in the recent past. This paper introduces a scalable and decentralized control algorithm for airborne guided weapon system, which aggregates the weapons into a given shape while reaching the surface. The proposed architecture is based on a two stage controller which uses...
The time and cost associated with the development and certification of flight-critical software have been escalating at an alarming rate for modern, software-enabled air vehicles. This upward trend is expected to continue as future vehicles will be increasingly autonomous and intelligent. Affordable, efficient processes and tools are needed to control development costs and schedule, as well as to...
NASA Ames, in collaboration with JSC ISS MOD, has been developing novel systems for searching across multiple heterogeneous data systems in order to facilitate rapid retrieval of relevant information for flight controllers on console and in their off-console duties. Traditional data mining techniques to identify document similarity rely upon brute-force O(n2) cosine similarity of vectors representing...
This paper describes a compact, lightweight power control unit suitable for a microsat. A COTS-based approach was used in component selection to enable short lead times and parts availability in addition to facilitating a lower cost. The five boards in the unit are similar in size to a 3U form factor and are packaged in a lightweight aluminum housing, include ldr Dual 200 W boost-mode battery chargers...
Mars Science Laboratory is a scientific mission to deliver a rover with ten science instruments to the surface of Mars. In order to accomplish this, a cruise stage and entry vehicle, which is comprised of an aeroshell and descent stage, are used. The backshell interface plate (BIP) interfaces to the backshell, the cruise stage and the descent stage. Also attached to the BIP is the parachute support...
The OSTM/Jason 2 mission will be the lightest payload to ever launch on a 2-stage Delta II 7320-10 launch vehicle. The moment-based lateral loads predicted for this launch configuration significantly exceed the qualification history of the inherited spacecraft bus. Additionally, payload sine vibration requirements for this launch configuration exceed the OSTM/Jason 2 spacecraft and equipment sine...
Projected demands for future space missions, where on-board sensor processing and autonomous control rapidly expand computational requirements, are outpacing technologies and trends in conventional embedded microprocessors. To achieve higher levels of performance as well as relative performance versus power consumption, new processing technologies are of increasing interest for space systems. Technologies...
Ultra-low power consumption often comes at the price of reduced performance for energy conscious electronics - particularly reconfigurable circuits. Operating devices at ultra-low voltage levels provides the lowest energy per operation, but can penalize the frequency of operation by several orders of magnitude. A more optimized approach is to segregate the logic based on performance requirements and...
High reliable reconfigurable applications today require system platforms that can easily and quickly detect and correct single event upsets. This capability, however, can be costly for FPGAs. This paper demonstrates a technique for detecting and repairing SEUs within the configuration memory of a Xilinx Virtex-4 FPGA using the ICAP interface. The internal configuration access port (ICAP) provides...
The constellation program mission operations project office (CxP MOP) at Johnson Space Center in Houston Texas is preparing to support the CxP mission operations objectives for the CEV/Orion flights, the Lunar Lander, and Lunar surface operations. Initially with the retirement of the Shuttle, the Orion will provide access to the International Space Station, then progress to the lunar missions. While...
The rapid integration, launch, and deployment of satellites in response to emerging needs have been a focus of various organizations. This concept has been termed "operationally responsive space" (ORS) by the United States Department of Defense (USDOD). One vision of ORS calls for the positioning in a depot of interchangeable satellite payloads and spacecraft buses with a common interface...
As previously reported [1], it may be possible to launch payloads into low-Earth orbit (LEO) at a per- kilogram cost that is one to two orders of magnitude lower than current launch systems, using only a relatively small capital investment (comparable to a single large present-day launch).11 An attractive payload would be large quantities of high-performance rocket propellant as required for the exploration...
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