Title of Paper: Adaptive Management of Computing and Network Resources for Real-Time Sensor Webs
Principal Author: Dr. Lonnie Welch
Abstract: In order to transition from large, instrument-jammed observatories to cheaper and lighter space-based platforms, NASA's Earth Science Vision Initiative has formulated the notion of a sensor-web, a closely integrated constellation of earth observing satellites that collectively monitor the conditions of our planet through a vast array of instruments. The network of satellites will act autonomously in controlling instruments and spacecraft, while also responding to the commands of the user interested in measuring specific events and to important terrestrial events. It is likely that NASA's future spacecraft systems will consist of distributed processes which will handle dynamically varying workloads in response to perceived scientific events, the spacecraft environment, spacecraft anomalies and user commands. Since all situations and possible uses of sensors cannot be anticipated during pre-deployment phases, an approach for dynamically adapting the allocation of distributed computational and communication resources is needed. Even if it were possible to anticipate all possible use case scenarios of future sensor webs, dedicating computational and communication resources based on maximum requirements will be far more expensive than employing an adaptive resource management system. To address these issues, we are evolving the DeSiDeRaTa resource management middleware to accommodate (1) the dynamic aspects of intra-constellation network topologies and (2) the complete real-time path from the instrument to the user.
Future autonomous satellites will perform much of the event detection and response processing that is presently performed by ground-based systems. They will perform on-board processing of sensor data through the use of high performance processing architectures and reconfigurable computing environments. Thus, we will demonstrate the feasibility of adaptive resource management for a ground-based command and control system currently used by several NASA satellite systems. In addition to showing feasibility, this will provide a ground-based testbed that will enable NASA to perform early evaluation of sensor web management techniques.