Rick Alena

ISHM Implementation for Constellation Systems

Integrated System Health Management (ISHM) is a capability that focuses on determining the condition (health) of every element in a complex System (detect anomalies, diagnose causes, prognosis of future anomalies), and provide data, information, and knowledge (DIaK) not just data to control systems for safe and effective operation. This capability is currently done by large teams of people, primarily from ground, but needs to be embedded on-board systems to a higher degree to enable NASAs new Exploration Mission (long term travel and stay in space), while increasing safety and decreasing life cycle costs of systems (vehicles; platforms; bases or outposts; and ground test, launch, and processing operations). This viewgraph presentation reviews the use of ISHM for the Constellation system.

Analysis and testing of mobile wireless networks

As the technology matures, wireless networks are being used in more applications providing significant benefits to mobile users. There are now many products, complying with wireless network standards 802.11 and 802.11b, for linking mobile computing elements together and into the Internet using radio signals. Wireless networks provide mobility, but offer lower reliability and performance compared to wired networks. Standard methods of analyzing and testing wireless network throughput and compatibility are needed to determine current performance limits of this technology. This paper presents experimental methods of determining wireless network product throughput, latency, range and coverage in the outdoor environment. Field test results from two representative 802.11 and 802.11b products are presented. Radio frequency (RF) domain analysis was performed on the same products allowing calculation of theoretical maximum throughput and range. Comparison of the outdoor field-test data with performance predicted from RF analysis yielded quantitative results applicable to future communication system design.

Communication system architecture for planetary exploration

Future human missions to Mars will require effective communications supporting exploration activities and scientific field data collection. Constraints on cost, size, weight, and power consumption for all communications equipment make optimization of these systems very important. These information and communication systems connect people and systems together into coherent teams performing the difficult and hazardous tasks inherent in planetary exploration. The communication network supporting vehicle telemetry data, mission operations, and scientific collaboration must have excellent reliability and flexibility. We propose hybrid communication architectures consisting of space-based links, a surface-based deployable mid-range communications network and a cluster of short-range links to solve the problems of connectivity and bandwidth, while meeting the other constraints of weight and power. A network of orbiting satellites could cover much of the planet surface, but this space-based capability may not be optimal for cost or performance. Specifically, a minimal space-based capability can be augmented using mobile cellular repeaters deployable by robots and human EVA. This method results in an increase in the number of radio nodes, but the distances separating them is decreased. This results in a significant increase in bandwidth and decrease in radio power, and therefore, node size, complexity, and power consumption. This paper will discuss the results of field testing such hybrid radio systems for the support of scientific surveys. System analysis of design tradeoffs will yield insight into optimal solutions that will be compared to other approaches providing a method of effectively evaluating new candidate architectures.

Mobile network field testing at HMP-2000

Future human planetary exploration field teams will need daily communications with their base and with mission control. A remote field wireless digital network will be a requirement for safe and productive human exploration. Proper selection of radio-frequency hardware and antennas will be vital to its success in remote, hostile environments. This paper reviews the communications techniques explored in the Mobile Exploration 2000 field season at the Haughton-Mars Project, which was located at a remote impact crater field science site in the Canadian Arctic. Results from 2.4 GHz spread-spectrum signal-strength and data throughput tests, conducted during remote field deployments, show a marked variability with given hardware and antenna choices, with directional antenna performance less than expected from theory. Changing the antenna schemes for repeater-to-base and repeater-to-rover increased the rovers effective communication range to base camp to over 3 km.

From research to operations: integrating components with an aspect-oriented framework and ontology

Bringing technology from the research world into an operational environment poses many challenges. Typically, software systems having their origins in low technical readiness level research projects have few, if any, formal requirements associated with them. This paucity of formal requirements coupled with the challenges associated with coordinating multiple, distributed research-oriented software projects makes it difficult to design and build software systems that will ultimately be useful in an operational environment. Targeted for current and next-generation space vehicles, the diagnostic applications that compose the advanced diagnostic system (ADS) under development in our lab at NASA-Ames Research Center are realizations of research projects associated with multiple organizations and generally are not designed according to stringent requirements nor with integration into the ADS environment in mind. The core functionality of a Diagnostic Client Application, usually having its basis in artificial intelligence research, is the primary (and perhaps sole) consideration of the application developer. Research funds generally are not available for implementing aspects such as logging and security, both of which are critical in aerospace diagnostic systems such as the ADS. Aspect-oriented programming (AOP) is a new software development methodology that complements object-oriented programming and addresses the complexity of software systems by achieving a separation of functional and interaction components (aspects). Aspects such as logging and security are defined as properties that cut across groups of functional components (diagnostic applications). Aspects can be thought about and analyzed separately from each other and from the core functionality of the software system. AOP provides the modular separation of crosscutting concerns, where the aspect code is scattered/tangled throughout the software system. An AOP framework takes advantage of what AOP provides and enables us to build software systems that can be extended and adapted during runtime. In this paper we present an AOP framework for integrating software components into an advanced (artificial intelligence-based) diagnostic system and introduce a basic ontology for sharing knowledge between a community of diagnostic applications (agents).

A scalable, out-of-band diagnostics architecture for international space station systems support

Daryl P. FletcherScience Applications International Corporation (SAIC)NASA Ames Research CenterMoffet Field, CA. 94035650-604-0159dpfletcher@mail.arc.nasa.govRick AlenaNASA Ames Research CenterMoffet Field, CA. 94035650-604-0262ralena@mail arc nasa.oovAbstract--The computational infrastruc_tre of theInternational Space Station (ISS) is a dynamic system thatsupports multiple vehicle subsystems such as Caution andWarning, Electrical Power Systems and Command and DataHandling (C&DH), as well as scientific payloads of varyingsize and complexity The dynamic nature of the ISSconfiguration coupled with the increased demand forpayload support places a significant burden on theinherently resource constrained computational infrastructureof the ISS. Onboard system diagnostics applications arehosted on computers that are elements of the avionicsnetwork while ground-based diagnostic applications receiveonly a subset of available telemetry, down-linked via S-band communications.In this paper we propose a scalable, out-of-band diagnosticsarchitecture for ISS systems support that uses a read-onlyconnection for C&DH data acquisition, which provides alower cost of deployment and maintenance (versus a highercriticality read/write connection). The diagnosticsprocessing burden is off-loaded from the avionics networkto elements of the on-board LAN that have a lower overallcost of operation and increased computational capacity. Asuperset of diagnostic data, richer in content than theconfigured telemetry, is made available to AdvancedDiagnostic System (ADS) clients running on wirelesshandheld devices, affording the crew greater mobility fortroubleshooting and providing improved insight intovehicle state. The superset of diagnostic data is madeavailable to the ground in near real-time via an out-of banddownlink, providing a high level of fidelity between vehiclestate and test, training and operational facilities on theground.