Acknowledgments

This book presents results of research carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

As editor and authors, we acknowledge the constant advice, help, comments, and encouragement from Joseph H. Yuen, the editor-in-chief of the Deep Space Communications and Navigations Systems (DESCANSO) series. David J. Bell's thorough review resulted in much improved clarity and completeness of the spacecraft chapters. In addition, they acknowledge the always helpful inputs and advice of Roger V. Carlson, the JPL editor.

Chapter 1, Telecommunications Link Analysis, lays out the principles and the statistical mathematical models for the design control table, or "link budget" in much the original form created by its author Joseph H. Yuen in the 1970s. We have retained this form in sections of Chapter 1 basically unchanged from the version as written by Dr. Yuen in the 1982 edition of Deep Space Telecommunications Systems Engineering.

Chapter 2, the Deep Space Network, draws extensively from the Deep Space Network (DSN) Telecommunications Link Design Handbook (810-005) as do sections of the other chapters. As the DSN evolved, many people have created and updated the material in the modules of this handbook. For this chapter we are most indebted to Robert Sniffin, the principal author and editor of the handbook for many decades. Some of the modules in 810-005 carry the names of the principal authors of those modules. In addition, numerous individuals, far too many to name, have contributed to the technology that is documented in their papers in the Interplanetary Network (IPN) Progress Reports. This technology has gone into the stations and the control centers, the hardware and software development, the thorough testing involved for each new system or software update, and the continued operation of the network in support of the missions represented in the following chapters.

Each of the remaining chapters describes the telecommunications system aboard a particular spacecraft. Each such subsystem operates in one to three frequency bands and consists generally of multiple antennas and their routing elements, one or more transponders or individual receivers and transmitters, and the command-receiving and telemetry-generating elements. Each subsystem involved the efforts and time of dozens of individuals or teams that developed the technologies, the functional design, the hardware, and the software. Many others performed the integration of the subsystem into the whole spacecraft and the testing before and after integration. The references in each chapter are those project documents, papers, conference proceedings, and websites that the coauthors and editor of this book drew on directly.

In Chapter 3, Voyager, much of the telecom design information was obtained from original Voyager prime mission design documentation: the design control document for the telecommunications links, the functional description of the telecommunications system, and the hardware design requirement for the modulation demodulation subsystem. Much of the mission and operational information was obtained from the Voyager Operational Handbook and the Voyager Neptune Travel Guide. The authors are grateful to Dave Bell, Kar-Ming Cheung, and Ed Massey for their Voyager background and development information.

For Chapter 4, Galileo, the authors express their appreciation to many individuals in the Interplanetary Network Directorate and the Telecommunications Science and Engineering Division (33) at JPL and other organizations who contributed directly to the success of the Galileo mission. In addition to the papers cited in the references, Richard Brace, Vic Albrecht, Rick Nybakken, and Gordon Wood, as the spacecraft telecom hardware cognizant engineers, oversaw the development and testing of the transponder, the modulation-demodulation subsystem, the antennas, and the ultra-stable oscillator. Prof. Wai-Kuen Cham of the Chinese University of Hong Kong invented the integer cosine transform (ICT) and helped to refine the ICT algorithm that was used as a form of lossy compression mostly for image data after the high-gain antenna (HGA) failed to deploy. The compression reduced the data volume to fit through the smaller bandwidth provided by the low-gain antenna link to Earth. Dr. Andrew Watson and Sherry Chuang at NASA Ames designed the ICT quantization matrix and performed subject tests with Galileo scientists to determine acceptable fidelity with ICT lossy compression. The authors are especially grateful to Eilene Theilig for her project systems perspective and to Steve Townes for his organizational recommendations that carried over to subsequent chapters.

For Chapter 5, Deep Space 1, the on-board telecom hardware development and testing was overseen by cognizant engineer Sam Valas and the antennas by Joe Vacchione. DS1 carried the first Small Deep Space Transponder, developed by Motorola with Keith Siemsen as the technical lead. Marc Rayman, as DS1 system engineer, added much to the clarity of the DESCANSO article the chapter is based on, as well as the success of the mission. The DS1 software team led by Dan Eldred helped the AutoNav team as it ventured for the first time into the realm of deep-space flight software. Finally, and perhaps most importantly, thanks go to the attitude control system (ACS) team, led by Sima Lisman, and including Tony Vanelli and Steve Collins. Besides their function of keeping the spacecraft pointed correctly, ACS was key to working with Jim Taylor of telecom to develop the HGA pointing workaround after the in-flight failure of the stellar reference unit.

For Chapter 6, Mars Reconnaissance Orbiter (MRO), as well as for the two Mars rover missions (Mars Exploration Rover [MER] and Mars Science Laboratory [MSL]) that conclude the book, Chad Edwards was the Mars Program office sponsor, and Edgar Satorius was the relay link signal processing lead. Key to the technical and managerial success of the Electra relay radio program development was Tom Jedrey. Eric Schwartzbaum was the Electra program manager, Ann Devereaux was responsible for the baseband processor, Ken Peters was responsible for software, and Todd Ely was responsible for radiometrics. The Electra first flew in the MRO and first operated on the surface in MSL. As MRO telecom lead, Stan Butman provided several suggestions and graphics for the chapter. Ricardo Mendoza conceived and developed the data volume capability file that is fundamental for science data return planning for all the Mars relay missions and inter-project coordination. The authors are grateful to David Bell, Tom Jedrey, and Ramona Tung for the information they contributed to the descriptions of the Electra transceiver and its use in relaying information with landers on the surface. We thank Charles Lee for the surface communications opportunities simulation, James Border for the information on delta differential one-way ranging (delta-DOR), and David Morabito for the discussion of solar conjunction effects on communications and the experiment plans during the MRO solar conjunctions.

For Chapter 7, Mars Exploration Rover, the authors express their appreciation to Brian Cook and Peter Ilott for the wealth of information on the heritage, performance, and testing of the X-band and UHF subsystems, respectively. Thanks also to Bill Adams, the Odyssey and MGS Flight Team Telecom lead at Lockheed Martin Aerospace. We also, thank Jan Ludwinski, whose excellent mission plan became an integral part of this chapter. The authors are grateful to Monika Danos, for scripts that made summaries of data from years of MER prime and extended mission flight operations consistent. Ramona Tung and Ricardo Mendoza were key to developing seamless relay link prediction capabilities involving the geometric intricacies of a roving surface vehicle working with several relay orbiters. Finally, the authors are indebted to Ed Satorius, Sue Finley, Christine Chang, Doug Johnston, Dave Fort, and Sami Asmar for their contributions to the analysis, development, testing, and operation of the Entry, Descent, and Landing (EDL) Data Analysis (EDA) system that enabled the return of the intricate series of signals with their rapidly varying signal levels and frequencies.

For Chapter 8, Mars Science Laboratory, the authors appreciate the access to information and documents provided by members of the MSL spacecraft development, test and flight operations teams. Many of those acknowledged for MRO and MER also participated in MSL. Peter Ilott was the telecom cognizant engineer and provided "better art" for many of the graphics in this chapter. Melissa Soriano, Sue Finley, and Polly Estabrook developed the EDA configuration to receive the X-band signal during EDL. Melissa Soriano, Sue Finley, Kamal Oudrhiri, and Daniel Kahan tested and operated the EDA and Radio Science Receiver during EDL. Mazen Shihabi and David Bell adapted telemetry analysis tools, first developed by Brad Arnold and Tom Jedrey, to rapidly process analyses of relay link performance the first month post-landing. This led to the successful "tuning" of the MRO Electra radio to overcome electromagnetic interference from MRO science instruments that degraded the MSL relay link performance. The new adaptive data rate mode, first used on the MSL/MRO return link was also tuned to maximize data return volume. Much of the information on spacecraft configuration, the...