Browsing International Telemetering Conference Proceedings, Volume 40 (2004) by Authors
Using the CCSDS File Delivery Protocol (CFDP) on the Global Precipitation Measurement missionRay, Tim; NASA (International Foundation for Telemetering, 2004-10)The Consultative Committee for Space Data Systems (CCSDS) developed the CCSDS File Delivery Protocol (CFDP) to provide reliable delivery of files across space links. Space links are typically intermittent, requiring flexibility on the part of CFDP. Some aspects of that flexibility will be highlighted in this paper, which discusses the planned use of CFDP on the Global Precipitation Measurement (GPM) mission. The operational scenario for GPM involves reliable downlink of science data files at a high datarate (approximately 4 megabits per second) over a space link that is not only intermittent, but also one-way most of the time. This paper will describe how that scenario is easily handled by CFDP, despite the fact that reliable delivery requires a feedback loop.
The Wallops Flight Facility Rapid Response Range Operations InitiativeKremer, Steven; Bishop, Jim; NASA; LJT and Associates, Inc. (International Foundation for Telemetering, 2004-10)While the dominant focus on short response missions has appropriately centered on the launch vehicle and spacecraft, often overlooked or afterthought phases of these missions have been the launch site operations and the activities of launch range organizations. Throughout the history of organized spaceflight, launch ranges have been the bane of flight programs as the source of expense, schedule delays, and seemingly endless requirements. Launch Ranges provide three basic functions: (1) appropriate geographical location to meet orbital or other mission trajectory requirements, (2) project services such as processing facilities, launch complexes, tracking and data services, and expendable products, and (3) safety assurance and property protection to participating personnel and third-parties. The challenge with which launch site authorities continuously struggle is the inherent conflict arising from flight projects whose singular concern is execution of their mission, and the range’s need to support numerous simultaneous customers. So, while tasks carried out by a launch range committed to a single mission pale in comparison to efforts of a launch vehicle or spacecraft provider and could normally be carried out in a matter of weeks, major launch sites have dozens of active projects with dozens of separate sponsoring organizations. Accommodating the numerous tasks associated with each mission, when hardware failures, weather, maintenance requirements, and other factors constantly conspire against the range resource schedulers, make the launch range just as significant an impediment to responsive missions as launch vehicles and their cargo. The obvious solution to the launch site challenge was implemented years ago when the Department of Defense simply established dedicated infrastructure and personnel to dedicated missions, namely an Inter Continental Ballistic Missile. This however proves to be prohibitively expensive for all but the most urgent of applications. So the challenge becomes how can a launch site provide acceptably responsive mission services to a particular customer without dedicating extensive resources and while continuing to be cost effective and to serve other projects? NASA’s Wallops Flight Facility (WFF) is pursuing solutions to meet exactly this challenge. NASA, in partnership with the Virginia Commercial Space Flight Authority, has initiated the Rapid Response Range Operations (R3Ops) Initiative. R3Ops is a multi-phased effort to incrementally establish and demonstrate increasingly responsive launch operations, with an ultimate goal of providing ELV-class services in a maximum of 7-10 days from initial notification. This target will be pursued within the reality of simultaneous concurrent programs, and ideally, largely independent of specialized flight system configurations. WFF has recently completed Phase 1 of R3Ops that included an in-depth collection (through extensive expert interviews) and limited software modeling of individual launch operations processes by various range disciplines. This modeling is now being used to identify existing inefficiencies in current procedures within each process and to show interdependencies. Existing practices are being tracked to provide a baseline as new procedures are implemented and evaluated. Technology infusion efforts have been identified and are currently underway in the area of space-based range safety and communications. Phase II of this effort will involve evaluation and implementation of real time software process flow tools, software integration of processes already defined into an integrated model, and spiral software development of the process flow tools. The technology efforts will begin maturing with flight demonstrations and integration into the operational environment. The completion of Phase II will enable R3Ops efficiencies to meet the requirements of many upcoming commercial and government programs. A critical duty in this phase will be the identification of an effective software tool that meets launch range requirements in a responsive multi-user environment.