THE NASA DATA SYSTEMS STANDARDIZATION PROGRAM RATIONALE AND SCOPE

Abstract

An unprecedented challenge to NASA’s data systems is presented by the operational Space Transportation System and the attendant planned permanent facilities in space. Large, extremely high data rate experiments are now possible. More importantly, re-visit capabilities permit in-orbit payload change-out, precluding conventional ground testing of the total system. End-to-end data system engineering and flexible architectural design are mandatory if this challenge is to be met economically and effectively. A simple, top-level logical reference model of the end-to-end data system is being developed, which identifies the numerous functions and services which every automated space data system must provide. Each function or service may be mapped into specific physical subsystems, so that interface relationships are evident and “standard” protocols may be identified for development. By virture of this interface standardization, subsystems can be designed not only independently and in parallel, but with confidence that when the subsystems are aggregated the end-to-end system will operate efficiently and at low cost. A second purpose of the model is to identify technical opportunities for interoperability between the space data networks owned by different agencies or countries, thereby promoting cooperative international cross support of space missions. Fully-automated virtual connection between an investigator and a sensor in space is postulated, with the intervening system being fully transparent regardless of the physical configuration or ownership of that system. To date this standardization effort has been principally directed toward a problem unique to space missions, namely the space to ground link. Mature “Guidelines” have been prepared for the formatting and coding of telemetry data, and these guidelines are being coordinated with approximately 12 other countries who have significant space activity. Other developmental Guidelines include telecommand formats and protocols, timetags, radio frequency/modulation techniques, and globally interpretable methods for the exchange of many different types of message data. A formal work-flow has been established whereby these Guidelines progress from concept papers to initial drafts (“White Books”) , then through iterative review cycles where they exist as Drafts (“Red Books”) and finally as completed Guidelines (“Blue Books”). This paper will review the overall program of data system standardization currently underway within NASA.