Science and Mission Control Center for the IMAGE mission*

R. J. Burley, J. L. Green, S. E. Coyle

NASA Goddard Space Flight Center, Greenbelt, MD, USA

*Paper presented at the 2nd International Symposium on Reducing the cost of Spacecraft Ground Systems and Operations, Oxford, UK, July 21-23, 1997.

Abstract

The Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) mission is the first NASA mission in a series of mid-sized explorers (MIDEX). All seven of the IMAGE instruments will be used to study the global response of the magnetosphere to changes in the solar wind in new and unique ways. The mission will utilize neutral atom, ultraviolet, and radio imaging techniques. IMAGE is currently planned for launch in January 2000.

In order to drive the design of new spacecraft and ground systems towards lower operations costs, the MIDEX flight series required a fixed mission operations and data analysis (MO&DA) budget for the life of the mission. The total MO&DA budget for IMAGE is not to exceed $15 million US dollars. This fixed budget has provided the impetus to re-examine, and to change, the existing mission operations paradigm at the Goddard Space Flight Center (GSFC).

To keep within the cost cap of operating the IMAGE mission for three years the IMAGE project is pioneering a new mission and science operations concept for NASA. This concept involves a number of important elements such as:

As implemented by the IMAGE project, the move away from the traditional ground systems developed at GSFC will both greatly reduce operations costs, and, greatly reduce development costs for the IMAGE mission and for other spacecraft in the MIDEX mission series.

1.0 Introduction

The Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) mission (http://image.gsfc.nasa.gov/) is the first of the new MIDEX series of medium-class explorer spacecraft. The overall objective of IMAGE is to determine how the magnetosphere responds globally to the changing conditions in the solar wind. Specific questions to be addressed include (1) what are the dominant mechanisms for injecting plasma into the magnetosphere on substorm and magnetic storm time scales? (2) what is the directly driven response of the magnetosphere to solar wind changes? and (3) how and where are magnetospheric plasmas energized, transported, and subsequently lost during storms and substorms? The IMAGE mission will use four imaging techniques to address these questions: neutral atom imaging (NAI) over an energy range from 10 eV to 200 keV, far ultraviolet imaging (FUV) at 121 - 180 nm, extreme ultraviolet imaging (EUV) at 30.4 nm, and radio plasma imaging (RPI).

In order to drive the design of new spacecraft and ground systems towards lower operations costs, the MIDEX flight series required a fixed mission operations and data analysis (MO&DA) budget for the life of the mission. The total MO&DA budget for IMAGE is not to exceed $15 million US dollars. This fixed budget for IMAGE, indeed with declining MO&DA budgets for all NASA missions, life cycle cost reductions have become a major driver in Goddard Space Flight Center (GSFC) development and orbital operations tasks, and has provided the impetus to re-examine, and to change, the existing mission operations paradigm at GSFC.

2.0 The Past

Since the earliest missions at the Goddard Space Flight Center, the design, development and operation of the ground systems have all been based on a facilities-oriented design. All mission functions including; mission control, spacecraft control, payload control, orbit determination and control, attitude determination, calibration and control, mission planning, and science data processing and distribution, all were performed in separate facilities, on separate hardware, and developed by separate teams. These facilities often had redundant functionality. Different mission phases, including component development, integration and test, and on-orbit operations, were usually done by different teams, from different organizations, using different systems. Each of these different facilities or teams created or reused it's own hardware, software, development process, development and operations staff, review processes, database and documentation. This resulted in inefficient transitions between spacecraft development phases, repeated work, and a fragmented product. The most severe fragmentation occurred between I&T and on-orbit operations. Work and knowledge were nearly completely duplicated as the spacecraft transitioned from I&T to on-orbit operations at launch.

Then, as mission budgets tightened, end-to-end system engineering was substituted with the mandate to reuse as much as possible from previous missions, even if this reuse included now-obsolete systems and/or processes and infrastructure. Significant reinvestment into new systems and new mission implementation processes were superseded by the budget-imposed requirement to minimize system change. What development did still occur, was optimized to minimize development costs. Because MO&DA costs were mostly funded from a different source, operations efficiency was rarely a design driver.

What resulted was a complex infrastructure of entrenched, expensive multi-mission facilities and systems, which although they were adaptable to new missions, they were expensive to operate and maintain, and ill-prepared for the changing times.

[Figure 1]

The preceding diagram shows the interfaces and the number of facilities involved in the day to day data flow within the SOHO ground data system.

The following table shows the current system manpower staffing required to support the GSFC elements of the ISTP ground data systems:

Category FY 97 Staffing
Flight Dynamics Facility 22
Flight Operations Teams IMP 1
Wind/Polar 17
SOHO 22
Science Planning & Operations Facility 8
Experiment Operations Facility 5
Data Processing Centers Central Data Handling Facility 19
Data Distribution Facility 10
Packet Processor Facility 9
Data Capture Facility 34
Maintenance 22
Management (includes QA, admin,
configuration control and test teams)		 38
Total FTE's 207

Note: these are "ballpark" figures. Re-engineering efforts are currently underway to reduce ISTP operations costs by 70% to enable the extended ISTP mission phase thru 2001 without compromising scientific goals.

As mission budgets have shrunk even further, it is obvious that it has become impossible to sustain this level of infrastructure any longer. New ground system designs and development and operations concepts are needed.

3.0 Lessons Learned

Despite the undisputed technical success of mission operations at GSFC, MO&DA costs were correctly judged to be too high. A series of technical reviews and papers focusing on the impact of missions operations on life cycle costs, identified several key ground system design features or practices that adversely affected the mission operations life cycle cost. Among the many NASA-level recommendations made by the "Mission Operations Evaluation Team Report for Space Physics Mission Operations and Data Analysis" report to NASA HQ on February 27, 1995, by Gael Squibb1 were:

Research into the life-cycle costs of science data archiving is documented in the paper "A Comprehensive Cost Model for NASA Data Archiving"2 by Dr. James Green of the National Space Science Data Center which analyses the factors which affect data archiving costs. Among the many evaluations made by this paper were:

The design of the new IMAGE ground data system is predicated on these observations, and on the direct experience of a diverse group of systems developers from across the Goddard Space Flight Center, including members of the Mission Operations Directorate, the Engineering Directorate, and the Science Directorate.

4.0 The Present

The IMAGE ground data system is pioneering a new ground system design and operations concepts at the Goddard Space Flight Center. The fundamental characteristic of it's design is the consolidation of all missions operations and science operations into a single operations facility called the SMOC (Science and Missions Operations Center). The consolidation of facilities also allows us to consolidate the system development team, and minimize it's size. It allows us to consolidate mission operations into a single facility, which minimizes the size of the operations staff required to operate and maintain the system. This co-location and consolidation fosters the communication between the subsystem developers which is critical to mission success, and eliminates a layer of management that existed in previous, facilities-oriented designs. This activity is both preceding, and to some extent driving, the current restructuring of the Goddard Space Flight Center. Consolidation has additional benefits. This consolidation, and adoption of industry standards for all data communications minimizes the number of interfaces within the system, which reduces both development and system validation efforts, which also facilitates the automation of the system.

[Figure 2]

The IMAGE ground system team has been given the opportunity to reengineer the spacecraft and ground system development process as well by creating a single ground system solution to support all mission phases including component development, integration and test (I&T), launch site operations, and on-orbit spacecraft and instrument operations. The ground system, project database, page displays and procedures are developed in conjunction with each stage of spacecraft development. Substantial cost savings accrue with the elimination of multiple ground system development efforts, elimination of transitions between spacecraft development phases and all its requisite product generation. Knowledge retention is maximized is achieved by involving the Spacecraft Control Team (SCT) in all aspects of the IMAGE project from spacecraft and payload development through on-orbit operations.

The IMAGE ground system is being implemented with a design that is baselined for unattended on-orbit operations. This is possible because the spacecraft and payload itself is designed to be operated in a low-maintenance manner, with a self-safing spacecraft and payload, and adequate power, thermal and data margins. Lights-out operations is the norm for the mission, with nominal activity planning, trend analysis and anomaly resolution being the primary manual efforts. Further reductions in the size of the SCT is being achieved through the use of an expert system for spacecraft and instrument health and safety monitoring. The expert system will use a C-Language Integrated Production System (CLIPS) rules base to monitor spacecraft and instrument health and safety telemetry as it is received in the SMOC, and will page the on-call member(s) of the operations staff if and when a hazardous condition has been detected, or if the telemetry has not been received when expected.

The generation of over 40 Level-Zero and Level-One science data products per day will be integrated into a single automated data pipeline. This includes the automated initiation of science data processing after a pass has been completed, and automatic forwarding of all data products to a publicly accessible web-server for immediate availability and distribution. The science return generated by the IMAGE mission is being maximized by the adoption of a public domain data standard for which a wide variety of data already exists, and for which a suite of support software already exists. This standard is the Common Data Format (CDF), which is a portable, self-documenting, self-describing data format developed and maintained by the National Space Science Data Center (NSSDC) at GSFC. Although it was originally defined as a science data format, it is equally applicable as an engineering data standard and is being utilized for trend analysis functions, and for orbit and attitude history functions.

Projected spacecraft control team staffing:

[Figure 3]

The data policy of the IMAGE mission is that all data is immediately available to the public. No proprietary data rights or periods exist for the mission. This policy eliminates any requirements for the intermediate archiving of any data products. All Level-Zero and Level-One data products produced in the SMOC will be immediately forwarded to the National Space Science Data Center (NSSDC), the ultimate repository for the data, for permanent archive and for immediate distribution.

All of the subsystems in the SMOC have already been developed at Goddard in one organization or another, and been successfully operated in one facility or another. The IMAGE ground system is the first time that they all will be integrated together into a single mission operations system. These subsystems include:

* Front End Data Server (FEDS). Currently being ported from an expensive VME equipment rack to a single Dec Alpha, this system receives, logs, and records CCSDS telemetry frames as they arrive over an IP network connection in the case of normal mission operations, or from an RS422 serial card in the case of spacecraft I&T phases. It performs frame-sync and Reed-Solomon decoding functions in software. It decommutates CCSDS source packets from the telemetry frames, and forwards the packets to any requesting process over a unix socket connection. It also performs all post-pass Level-Zero processing.

* Advanced Spacecraft Integration and System Test (ASIST). Provides real time command and control for spacecraft and payload control system applications. It is language driven with a distributed system capability and can be configured for a variety of applications and payload characteristics. It features advanced graphical and textual display capabilities, a STOL language driven decommutation application, integrated history archives, and extensive data export capabilities. ( http://rs733.gsfc.nasa.gov/ASIST/ASIST-home.html)

* Command Management System (CMS). Constructs, calculates, or ingests, spacecraft and payload command sequences, and antennae schedules and validates them. Handles both absolute and relative time sequences. Manages spacecraft on-board tables and memory loads. ( http://rs733.gsfc.nasa.gov/~csckg/cms.html)

* Generic Spacecraft Analysts Assistant (GENSAA). Uses a CLIPS rules base to monitor spacecraft and payload health and safety parameters, and SMOC system status. ( http://groucho.gsfc.nasa.gov/Code_520/Code_522/Projects/GenSAA/)

* Multi-Mission Single Axis Satellite System (MSASS). Recently converted to a MATLAB application, this system performs the routine validation of the OBC-derived attitude by receiving attitude sensor data, computing the spacecraft attitude, and comparing this to the OBC-derived attitude received in telemetry.

* Coordinated Data Analysis Website (CDAWeb). Uses a set of PERL programs to generate Common Gateway Interface (CGI) pages for a world-wide-web interface by examining it's science inventory database, and for automatically code-generating IDL (Interactive Data Language) programs to read and display data contained in CDF files. (See associated web pages: http://cdaweb.gsfc.nasa.gov/cdaweb/ , http://spdf.gsfc.nasa.gov/sp_use_of_cdf.html , http://spdf.gsfc.nasa.gov/ )

5.0 Summary - "Better - Faster - Cheaper"

The IMAGE ground data system, and it's companion MIDEX mission the Microwave Anisotropy Platform (MAP), are pioneering both new ground system designs and new mission development strategies at the Goddard Space Flight Center which will significantly lower both mission development and mission operations life cycle costs. Current budget projections indicate that the ground systems for these missions will cost between one-tenth to one-twentieth the cost of the ground systems for previous, similar, missions done by the GSFC. They will require only minimal operations staff support after launch and early orbit checkout due to consolidation of its facilities and staff, automation of routine functions, and because of a low-maintainence spacecraft and mission design.

BIOGRAPHY

Mr. Richard Burley is the Ground System Manager for the Imager for Magnetopause to Auroral Global Exploration (IMAGE) mission, which is being done at the NASA/Goddard Space Flight Center. His mission experience includes: Data capture, logging and playback system for the GSFC Trajectory Computations and Orbital Products Systems, Real-time magnetometer bias determination for GRO, Pitchback attitude maneuver commanding for COBE, Star Identification and fine attitude determination for UARS and EUVE, Telemetry simulation for WIND and POLAR, Telemetry processor for SAMPEX, was a member of the Common Data Format (CDF) team which won runner-up for NASA software of the year in 1995, is the primary developer of the Coordinated Data Analysis Web system (CDAWeb), and has been the author or co-author on four papers presented to the American Geophysical Union.

REFERENCES

1 Green, J. L., Klenk, K. F. and Treinish, L. A, A Comprehensive Model for Data Archiving, available from NSSDC/GSFC, Greenbelt, Maryland, August, 1990

2 Squibb, G. F., et.al., Mission Operations Evaluation Team Report for Space Physics MO&DA, available from NSSDC/GSFC, Greenbelt, Maryland, February 27, 1995

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Dr. D. R. Williams, dwilliam@nssdc.gsfc.nasa.gov, (301) 286-1258
NSSDC, Mail Code 633, NASA/Goddard Space Flight Center, Greenbelt, MD 20771

NASA Approval: J. L. Green, green@nssdca.gsfc.nasa.gov
Last Revised: 13 April 1998, DRW