--Dolly Perkins (dolly.perkins@gsfc.nasa.gov)
Deputy Associate Director for EOS Operations
NASA Goddard Space Flight Center
The AM-1 Flight Operations Team (FOT) is generally responsible for operating the spacecraft and instruments, which primarily include three main support functions: mission management; real-time command and control; and analysis of spacecraft and instrument performance and anomalies.
Mission management consists of planning and scheduling the onboard activities of the spacecraft subsystems and instruments, and constructing the associated command and memory loads for uplink. It also includes the management of onboard memory and of various ground system databases.
Real-time command and control involves monitoring the spacecraft and instrument health and safety, and dumping the recorded engineering and science data. It also includes issuing real-time commands needed to conduct planned operational activities and respond to anomalies, as well as uplinking the appropriate command and memory loads.
The analysis function is performed to trend and assess the overall performance of the spacecraft subsystems and instruments. Engineering data are gathered and analyzed to detect potential degradation of onboard components and to evaluate anomalies in greater detail.
The original EOC system was based on the Flight Operations Segment (FOS) architecture, which was developed under the EOSDIS Core System (ECS) contract by the Raytheon Systems Company and the Lockheed-Martin Corporation. A launch-ready system was originally scheduled to be delivered in September of 1997 to support a June 1998 AM-1 launch. However, NASA encountered major problems with the launch version, and decided to move the launch date to later in 1998. NASA and the ECS contractor agreed on a new FOS launch-ready delivery date of March 1998 to meet this change in launch schedule. The subsequent delivery in March contained many improvements, but still did not meet many of the launch critical requirements.
While the ECS contractor was again challenged to deliver a launch-ready FOS system, NASA GSFC also initiated a parallel effort to assess potential alternative architectures. This resulted in the implementation of an alternative control center prototype based primarily on the Epoch-2000 commercial command and control product developed by Integral Systems Incorporated (ISI). Based on the successful initial results of the alternative prototype, as well as the continued slow progress of the FOS recovery effort, Raytheon decided in September of 1998 to terminate efforts to complete the FOS. An alternative hybrid solution was chosen, utilizing a Raytheon commercially developed command and control product (Eclipse), the analysis component of the ISI Epoch-2000 product, and selected components of FOS. NASA and the ECS contractor developed a revised integrated schedule for completing the hybrid system and ensuring spacecraft and instrument operations team readiness. The revised plan calls for launch of the AM-1 spacecraft during the third quarter of 1999.
As shown in the figure, the revised hybrid architecture, known as the EOS Mission Operations System (EMOS), consists of three loosely coupled components. The components communicate via simple and clean interfaces, decreasing complexity of the overall system. The three components are the Online System, the Mission Management System, and the Analysis System.
The Online System supports the real-time command and control functions and utilizes the Raytheon Eclipse product. Eclipse evolved from control center software used by the Department of Defense in numerous classified programs and has significant heritage and maturity. Raytheon recently adapted the Eclipse product to the commercial ICO Global Communications program, resulting in a client/server architecture using DEC servers and Windows/NT PCs.
The Mission Management System reuses the planning & scheduling, command management, and data management components from FOS, which had reached an acceptable level of stability and maturity. Given the large amount of AM-1 -unique software in these areas, this approach avoided what otherwise would have been a major schedule impact. The new system is hosted on Sun/Unix workstations and utilizes the Sybase RDBMS to manage ground system data. A simple file interface is utilized to provide the various command and memory loads to the Online System for subsequent uplink. The system is being integrated by a combined Raytheon and ISI team.
The Analysis System provides all of the offline trending and statistics support. It is derived from the successful alternative architecture prototype, and is based on the ISI Epoch-2000 and Archive Browser Extracter (ABE) products. ISI is integrating this system as an ECS subcontractor to Raytheon.
The concept of remote instrument operations has been maintained under the EMOS architecture, with the Instrument Support Toolkit (IST) still being used to provide the Instrument Operations Teams (IOT) with planning and scheduling, real-time monitoring, and analysis support. The Mission Management and Analysis Systems will be hosted on the IOT Sun workstations. For the Online System, the ECS contractor will provide each of the IOT's with one or more Windows/NT PC's to host the Eclipse software.
The EMOS build approach is based on multiple builds through the development cycle in order to provide initial functionality to support early interface testing with the AM-1 spacecraft, to expedite the development of operations procedures and display pages, and to initiate flight and instrument operations training and simulations.
The first build was delivered in December 1998 and provides initial online functionality for real-time commanding, telemetry monitoring, and command procedure execution. It also provides nearly full functionality for the mission management and analysis components.
The second build will be delivered in March 1999 and will provide all functionality needed to support the launch and early orbit phase of the mission. Additional builds will be delivered through launch and early orbit in order to facilitate normal operations.
In summary, while the problems with implementing FOS caused major delays in AM-1 ground system readiness, NASA and the ECS contractor are confident that the new hybrid architecture addresses the fundamental architectural problems that existed. The new architecture and the addition of many new and talented players to the team have rejuvenated the effort and lead NASA to feel much more confident about achieving a launch-ready system on the new schedule.