Computers in Spaceflight: The NASA Experience

Bibliographic Note and Interview List
 
 
Bibliographic Note:
 
The detailed references to sources given with each numbered note in the text serve as the primary record of the evidence used in writing this volume. This essay provides a general summary of the sources used and describes the method of locating and evaluating them. As the volume is a history of technology rather than an institutional history, the burden of the written evidence lies in technical reports, software documentation, training manuals, and feasibility studies rather than memoranda and executive orders. However, the latter sources often provide the time sense and structure that so quickly fades from an engineer's mind as he goes on to his next project. Because NASA's involvement in computer operations during the 1960s and 1970s mirrored the stumbling discovery of software engineering principles by other organizations, interviews not only with managers but programmers and contract liasons in both NASA and contractor offices are a major contribution to my understanding of the flow of events and their impact on later decisions and developments. Thus, the sources include the basic mix found in other NASA histories: written institutional records and oral interviews, with the addition of an extensive list of technical material.
 
Identification of source materials was conducted in several cycles. First, a comprehensive search through standard references, such as The Applied Science and Technology Index, was made to identify secondary sources that dealt with NASA's use of computers. The period surveyed was 1945 to 1981. Articles were found in journals such as Electronics, Journal of Spacecraft and Rockets, Journal of Guidance and Control, and various IBM, American Institute of Aeronautics and Astronautics, and American Federation of Information Processing Societies publications. This search revealed that even though NASA is critically dependent on computers for spaceflight operations, and that even though massive amounts of material have been written on the space program in general, relatively little has been published in public journals or in books on spaceflight specifically treating the use of computers. Most of what has been published is short and far from comprehensive. In books about space projects heavily dependent on computers, such as NASA's own Chariots for Apollo, generally nothing is said about the configuration, programming, or operation of those computers. Thus, the general public, even the technically sophisticated public, is largely in the dark about the specifics of NASA's computer use. That, of course, is one reason why this volume is needed.
 
The identification of primary source materials came next. Thanks to a Faculty Research Grant from Wichita State University, I was able to make a preliminary visit to the Johnson Space Center while preparing my contract proposal. This visit provided access to the RECON bibliographic retrieval system that NASA uses. RECON is especially valuable in this subject area because key words are rather liberally applied to each item stored: anything remotely to do with computers had a "computer" key word. Therefore, search keys could be developed such as "Apollo*Computers," and items with both those key words could be separated from the mass of material on Apollo. The RECON search netted over 1,000 items, of which about 25% were rejected based on their abstracts or because the other associated key words indicated that the item was primarily concerned with another subject, with only passing reference to computing. The remainder were physically examined in order to eliminate those that actually did not have pertinent materials. This process of reading the remaining sources and doing the interviews turned up a number of new primary sources. The bulk of these sources are software and hardware specifications, operations reports, flight training manuals, and spacecraft systems familiarization manuals, which are not indexed either in standard bibliographies or RECON.
 
Most items in the NASA archives at the various centers are not listed in RECON, so memoranda and other such unpublished items were discovered the "old-fashioned" way: by physically going through the files. My contract provided for visits to Johnson Space Center, Kennedy Space Center, Marshall Space Center, the Jet Propulsion Laboratory, Dryden flight Research Center, Goddard Space Center, and NASA Headquarters. Archives do not exist at either Marshall or Goddard, so individuals provided whatever new sources were gained at those places. In each of the other centers, a serious perusal of the materials relating to computer usage was done. At Johnson, the archives transferred to the Woodson Library of Rice University were also consulted.
 
The tour of the various NASA facilities demonstrated that those with full-time historians or archivists had the most useful archives. That is, of course, obvious, but it is interesting to contrast the situation at, say, Kennedy versus that at Marshall. Marshall has not had an archivist or historian since the early 1970s. There is no central repository. The only way information could be located was by finding division chiefs in the areas to be researched and then depending on them to help identify the people who had experience with the actual program. Those people could then be interviewed and some had kept copies of appropriate documentation. Others had not. For example, the entire story of the Saturn launch vehicle preflight checkout system is in danger of being lost. The people who built it are nearing federal retirement, they have thrown out almost all of the documentation, and their memories are clouded by the other projects in which they have been involved in the last 20 years. At Kennedy, even though a lot of interviews were conducted, the main source of information was the well-kept library and archives, which included a technical documents section. There the bulk of the story of the Shuttle Launch Processing System, the successor to the Saturn preflight checkout system, can be reconstructed from specifications, development reports, and user manuals. The point is that most of NASA will soon be in the state that Marshall is in. Johnson has lost its full-time historian, and the archives are maintained part-time by administrative personnel, with some items transferred to the Woodson Library. The latter facility has no provision for extensive xeroxing and is closed-shelf, two crippling defects for the historian with limited time on-site.
 
With no one at the various centers to choose what should be saved, documents are being lost at a prodigious rate. It is true that much paper generated by NASA is not needed for later historical research, but there is no apparent system of sifting out the material that has potential for later use. At the Jet Propulsion Laboratory, where files are regularly collected for archiving, there is no active control of what is sent to the records center. Some boxes contained organized, indexed files. Others looked as though someone had simply emptied their desk drawers into them; they contained such items as old copies of the employees' newsletter amidst notes and memos in no particular order. Additionally, project managers can choose to delete materials and thus prevent historians from gaining a balanced perspective.
 
Personnel assigned as history liasons at each NASA center, even if they had no historical experience, were unfailingly helpful and cooperative. They are mentioned and thanked individually in the Acknowledgments. By contacting them ahead of time, I was able to obtain the names of initial contacts, which led me to the large number of very candid interviewees whose collective memory adds so much to this book. They are listed at the end of this note. I was also able, through the individual efforts of interviewees, to obtain entry to areas normally restricted to the public. In that way I was able to see firsthand what I was writing about. There is no substitute for seeing the computers installed and operating and for looking at and using the crew interfaces. In that way, the true scale of things is established in the mind.
 
The remainder of this bibliographic note is a topic-by-topic summary of the main sources.
 
 
THE GEMINI DIGITAL COMPUTER
 
 
The most useful written source for the hardware section of the chapter on Gemini is the NASA Project Gemini Familiarization Manual, Volume 2, published by McDonnell Corporation in 1965. This manual contains a detailed hardware description of the Gemini digital computer, its location in the spacecraft, and drawings of the user interfaces. For the software development cycle and contents of the Gemini software loads, Project Gemini: A Technical Summary, (NASA CR-1106, 1968) by P. W. Malik and G. A. Souris, is the most comprehensive. Ivan Ertel, then of the Manned Spacecraft Center History Office, conducted extensive interviews with IBM personnel who worked on the Gemini computer during a visit to the Owego, New York plant in April of 1968. These interviews are transcribed and available at Johnson Space Center. They were very useful in identifying development problems and procedures. Lastly, interviews with Gene Cernan and John Young provided information about the system from the user standpoint.
 
 
THE APOLLO COMPUTER SYSTEMS
 
 
Sources for this chapter were primarily technical reports issued by the MIT Instrumentation Lab, memos on file at the Johnson Space Center, and some very illuminating interviews. The best hardware description of the Block II computer is in R. Alonso and A. L. Hopkins, The Apollo Guidance Computer (NASA-CR-1 18183, August 1963). An introduction to developing software for the computer is B. I. Savage and A. Drake, AGC4 Basic Training Manual (MIT, January 1967). Copies of these are available at Johnson Space Center. For NASA's view of the hardware and software difficulties in developing the onboard computer, the files of Howard W. Tindall are the most helpful. These are also at Johnson. The best interview sources for this chapter are John R. Garman of JSC and Stan Mann, formerly of JSC. Both were involved in the Apollo software development effort and later in the Shuttle program. Both were extremely candid and very informative. Transcribed interviews of David Hoag and Ralph Ragan of MIT were also helpful. Astronaut users Vance Brand, Gene Cernan, and John Young gave good insights in their interviews. For the Abort Guidance Section, the best source is P. M. Kurten, Apollo Experience Report: Guidance and Control Systems-Lunar Module Abort Guidance System (NASA-TN-D-7990, Johnson Space Center, Houston, TX, July 1975).
 
 
THE SKYLAB COMPUTER SYSTEM
 
 
The Skylab chapter is overwhelmingly based on two excellent sources, both produced by IBM Corporation. They are the Design and Operational Assessment of Skylab ATMDC/WCIU Flight Hardware and Software (IBM No. 74W-00103, May 9, 1974) and the Skylab Reactivation Mission (IBM No. 79W-0005, September 12, 1979). The Skylab hardware and software development was an operation largely local to Huntsville, Alabama, where IBM had a continuing corporate presence since the early 1960s when work on the computer systems for the Saturn launch vehicles began. These two sources are detailed histories of the development and use of the computer system in both the primary Skylab mission and the reactivation mission. They are quite frank, documenting both the first-time successes and needed restarts, although obviously proud of the highly reliable record of the system. By the time I reached Huntsville, the IBM office had closed, but some ATMDC programmers were still on-site working on Spacelab. By now, those few are scattered elsewhere. One, John Copeland, was kind enough to be interviewed and lent the reactivation documentation. Bill Chubb and Jim McMillion of Marshall Spaceflight Center were also very good sources on the computer system. Steve Bales of Johnson Space Center was able to give a perspective on the system from the flight controller's angle and was especially helpful regarding the first 2 weeks of the primary mission before the crew arrived.
 
 
THE SHUTTLE DATA PROCESSING SYSTEM
 
 
At the time this volume was being written, the Shuttle was an ongoing project. Therefore, abundant primary source materials in the form of actual requirements and design documents, program code, and managers involved in the day-to-day production of the hardware and software were available. Additionally, the astronauts have fresh memories, and the artifacts described in the chapter can be actually seen and touched. I decided to try to base this chapter on these sources as much as possible, plus my personal experiences in using the equipment and software in simulators. Thus, there are a great number of references to interviews (of which roughly 35 hours were done) and to current documentation. Despite this plethora of sources, some things could not be settled. An example would be the question of who thought up the eventual scheme used in redundancy management. No one could name a specific person or a time. Everyone asked about the subject said "it just evolved," or "no one person thought it up," both of which are true, but frustrating!
 
 
NASA STANDARD SPACECRAFT COMPUTER-1
 
 
Since the origination and development of this computer took place at one place, Goddard Spaceflight Center, it was relatively simple to find materials and persons. Ann Merwarth, Bill Stewart, and John Azzolini were the key informants in describing the design and capabilities of this device. Stewart led me to a documents distribution point where I was able to get copies of Merwarth's guide to the executive. A fine source of information is an article in the September 1984 issue of Communications of the ACM, authored by Merwarth, Stewart, and others, which tried to show the evolution of the system from its beginnings in the mid-1960s. A chapter on this computer, which was written for an early draft of the volume was later deleted because it was too much a restatement of previously published materials.
 
 
COMPUTERS ON DEEP SPACE PROBES
 
 
The Jet Propulsion Laboratory has three methods of archiving documentation. One is the "Vellum File," located in the basement of the Library and containing on microfilm all technical documentation used in projects. It is possible to obtain hard copy of critical documents, which I did when told of their existence by my informants. The Library itself contains indexes of publications written by JPL personnel, wherever published and holds copies of most of those in its collection. A third source, and one very critical for historians, is a central depository that contains memos and other unpublished documentation from the project offices and permanent section offices. Materials in this archive are arranged by JPL section number and stored in boxes. This collection is very erratic in quality. Almost all the materials cited in Chapters 5 and 6 were found in one of these three locations.
 
If the section on Galileo contains omissions, it might be because the project director refused to let me examine his and his chief deputy's office files. No reason was given. In the face of the existence of the actual documents, I thought it was foolish to speculate on any matters possibly contained within them, as a later historian can examine the materials after they are retired-assuming, that is, that they are not destroyed beforehand.
 
Personal contacts at the Lab were among the most satisfying I had in all my travels. Engineers at JPL are more introspective and more history conscious than others I have met. Their help is reflected in the actual notes to Chapters 5 and 6.
 
 
EVOLUTION OF LAUNCH PROCESSING
 
 
Documentation for this chapter was hard to come by, both because the information was scattered among Johnson, Marshall, and Kennedy Space Centers, and because pre-Shuttle primary sources at both Marshall and Johnson had been destroyed. However, the current Launch Processing System is heavily documented as to function because it is still operating. Also, Kennedy preliminary studies such as the Space Shuttle Launch Operations Study are in archives, and published summaries by IBM tended to be historical in nature. Therefore, the present System is easy to describe. For specifics of origin, though, I am again indebted to my informants, particularly Thomas S. Walton, who lived through the entire era at Kennedy, Jim Lewis of Marshall, Frank Byrne, the genius behind the common data buffer, and Henry Paul, who headed the development effort. A short manuscript history by Bill Bailey of Kennedy and an interview with him were also very helpful.
 
 
MISSION CONTROL
 
 
Fortunately, a fair amount of original source material is available on the subject of mission control. Documentation for the Mercury Control Center software system is contained in detailed IBM handbooks such as the "Goddard Monitor System," supplied by John Morton. He, J. Perry Chambers, and Ray Mazur were excellent sources of information on Goddard's Spaceflight Center's role both in manned and unmanned mission control. Philco's "IMCC Systems and Performance Requirements" study and IBM's proposal for the Gemini and Apollo mission control centers are the best sources for what was installed at the then Manned Spacecraft Center. Interviews with Lyn Dunseith and James Stokes helped considerably with that era. Shuttle mission control information is primarily based on interviews with Dub Pollen, Fred Riddle, and Gene Campbell of IBM and a publication by S. E. James of that company. Researchers interested in unmanned mission control of lunar and planetary probes should consult the final reports of the various Mariner, Viking, Ranger, Surveyor, and Voyager projects, usually issued as Jet Propulsion Laboratory technical reports. Each contains a detailed description of control considerations. George Gianopolis, Richard Moulder, Lloyd Jennings, Frank Singleton, Carl Johnson, and Don Royer, all of JPL, each contributed informative interviews for this section.
 
 
SIMULATIONS AND IMAGE PROCESSING
 
 
Again, interviews are the backbone of my understanding any materials analyzed for this chapter. Jim Raney, Bob Ernull, and Ken Mansfield of Johnson Space Center provided both knowledge and materials related to mission and engineering simulators. Jack Lucas and his staff at Marshall helped with the engineering simulators located there. Finally, Bob Nathan of JPL, founder of image processing, and his colleague Al Zobrist clarified the complex world of digital imaging. Almost all written materials used as sources for this chapter were either given to me by these informants, or they directed me to them. The monograph Digital Processing of Remotely Sensed Images, by Johannes G. Moik (NASA SP-431), is a good reference for NASA's work in this field.
 

Interview List:

 
 
Note: Unless identified otherwise, all persons on this list were NASA employees at the time they were interviewed. Locations are also indicated at the time of the interview.
 
AARON, JOHN, Johnson Space Center, June 17, 1983.
 
ALDRICH, ARNOLD, Johnson Space Center, June 13, 1983.
 
AZZOLINI, JOHN, Goddard Spaceflight Center, July 2, 1984.
 
BAILEY, WILLIAM, Kennedy Space Center, June 30, 1983.
 
BALES, STEVEN, Johnson Space Center, May 31, 1983.
 
BIEGERT, PAMELA, Kennedy Space Center, June 30, 1983.
 
BLIZZARD, EDGAR, Jet Propulsion Laboratory, May 29, 1984.
 
BOGAN, JACK, IBM, Kennedy Space Center, June 29, 1983.
 
BORNCAMP, FRANZ, Jet Propulsion Laboratory.
 
BRADFORD, CLIFFORD, Marshall Space Center, June 20, 1983.
 
BRAND, VANCE, Johnson Space Center, June 2, 1983.
 
BULKLEY, R.C., IBM, Kennedy Space Center, June 27 and 29, 1983.
 
BRUCKNER, BOBBY, Kennedy Space Center, June 30, 1983.
 
BYRNE, FRANK, Kennedy Space Center, June 29, and July 8, 1983.
 
CAMPBELL, GENE, IBM, Houston, June 13, 1983.
 
CERNAN, GENE, telephone interview from Houston, November 7, 1983.
 
CHAMBERS, J. PERRY, Goddard Spaceflight Center, June 28, 1984.
 
CHARLEN, WILLIAM, Jet Propulsion Laboratory, May 18, 1984.
 
CHUBB, WILLIAM, Marshall Space Center, June 22, 1983.
 
CLAYTON, ELDON, Johnson Space Center, June 1, 1983.
 
COPELAND, JOHN, IBM, Marshall Space Center, June 23, 1983.
 
COX, KENNETH, Johnson Space Center, June 14, 1983.
 
DEESE, SAMUEL, Jet Propulsion Laboratory, telephone interview, January 31, 1985.
 
DEETS, DWAIN, Dryden Flight Research Center, May 25, 1984.
 
DELAUNE, CARL, Kennedy Space Center, July 5, 1983.
 
DEMING, JAMES E., Kennedy Space Center, July 6, 1983.
 
DUNSEITH, LYNWOOD, Johnson Space Center, June 2 and 9, 1983.
 
EISENMAN, DAVID, Jet Propulsion Laboratory, May 21, 1984.
 
ERICKSON, JOHN, Johnson Space Center, June 14, 1983.
 
ERNULL, ROBERT, Johnson Space Center, June 16, 1983.
 
FOY, LYNNE, Johnson Space Center, June 16 and 17, 1983.
 
GARMAN, JOHN R., Johnson Space Center, May 25, and June 1, 1983.
 
GIANOPOLIS, GEORGE, Jet Propulsion Laboratory, June 4, 1984.
 
GREENBERG, EDWARD, Jet Propulsion Laboratory, May 30, 1984.
 
HART, TERRY, Johnson Space Center, June 10, 1983.
 
HARTSFIELD, HENRY, Johnson Space Center, June 2, 1983.
 
HEDDINS, FREDERICK, IBM, Kennedy Space Center, June 27 and 29, 1983.
 
HINSON SHIRLEY, Johnson Space Center, June 16, 1983.
 
HOELZER, HELMUT, Huntsville, Ala., June 24, 1983.
 
HUGHES, BRAD, Kennedy Space Center, July 5, 1983.
 
HUGHES, FRANK, Johnson Space Center, June 2, 1983.
 
JENNINGS, LLOYD, Jet Propulsion Laboratory, May 15, 1984.
 
JOHNSON, CARL, Jet Propulsion Laboratory, May 23, 1984.
 
JOHNSON, DONALD, Jet Propulsion Laboratory, May 16, 1984.
 
JORDAN, FRANK, Jet Propulsion Laboratory, May 31, 1984.
 
KILLINGBECK, LYNN, IBM, Houston, June 7, 1983.
 
KOHL, WAYNE, Jet Propulsion Laboratory, telephone interview, January 31, 1985.
 
KOPF, EDWARD H., Jet Propulsion Laboratory, May 18, 1984., telephone interview, January 31, 1985.
 
LANIER, RONALD, Johnson Space Center, June 16, 1983.
 
LEE, B. GENTRY, Jet Propulsion Laboratory, June 1, 1984.
 
LEMON, RICHARD, Jet Propulsion Laboratory, May 29, 1984.
 
LEWIS, JAMES, Marshall Space Center, June 20, 1983.
 
LINEBERRY, EDWARD, Johnson Space Center, June 2, 1983.
 
LOCK, WILTON, Dryden Flight Research Center, May 24, 1984.
 
LOUSMA, JACK, telephone interview from Houston, July 5, 1983.
 
LUCAS, JACK, Marshall Space Center, June 21, 1983.
 
MACINA, ANTHONY, IBM, Houston, June 7, 1983.
 
MALM, RICHARD, Jet Propulsion Laboratory, May 31, 1984.
 
MANN, STANLEY, Johnson Space Center, June 6 and 8, 1983.
 
MANSFIELD, KENNETH, Johnson Space Center, June 1, 1983.
 
MATTOX, RUSSELL, Marshall Space Center, June 23, 1983, telephone interview, November 16, 1984.
 
MAZUR, RAYMOND, Goddard Spaceflight Center, June 28, 1984.
 
McMILLION, JAMES, Marshall Space Center, June 22, 1983.
 
MERWARTH, ANN, Goddard Spaceflight Center, July 3, 1984.
 
MILLER, BRUCE, Kennedy Space Center, July 5, 1983.
 
MITCHELL, WALTER, Marshall Space Center, June 23, 1983.
 
MORECROF'T, JOHN, Jet Propulsion Laboratory, May 29, 1984.
 
MORTON, JOHN, Goddard Spaceflight Center, June 27, 1984.
 
MOULDER, RICHARD, Jet Propulsion Laboratory, May 21, 1984.
 
NATHAN, ROBERT, Jet Propulsion Laboratory, May 30, 1984.
 
OTAMURA, ROY, Jet Propulsion Laboratory, May 29, 1984.
 
PALIKOWSKY, RAYMOND, Singer, Houston, June 10, 1983.
 
PANCIERA, ROBERT, Marshall Space Center, June 20, 1983.
 
PARRISH, ALBERT, Kennedy Space Center, June 28, 1983.
 
PARTEN, RICHARD, Johnson Space Center, June 3 and 16, 1983.
 
PAUL, HENRY, Kennedy Space Center, July 7, 1983.
 
PENDLETON, THOMAS, Johnson Space Center, June 9, 1983.
 
PENOVICH, FRANK, Kennedy Space Center, July 1, 1983.
 
PETYNIA, WILLIAM, League City, TX, June 8, 1983.
 
POLLEN, DUB, IBM, Houston, June 13, 1983.
 
RAINES, GARY K., telephone interview from Houston, November 1, 1985.
 
RANDALL, JOSEPH, Marshall Space Center, June 20, 1983.
 
RANEY, JAMES, Johnson Space Center, May 31, 1983.
 
RICE, RICHARD, Jet Propulsion Laboratory, May 29, 1984.
 
RIDDLE, FREDERICK, IBM, Houston, June 13, 1983.
 
RONE, KYLE, IBM, Houston, June 3, 1983.
 
ROYER, DONALD, Jet Propulsion Laboratory, June 7, 1984.
 
SINGLETON, FRANK, Jet Propulsion Laboratory, May 17, 1984.
 
SMITH, GEORGE, IBM, Kennedy Space Center, June 27 and 29, 1983.
 
STEARNS, JANE, Kennedy Space Center, June 30, 1983.
 
STEWART, WILLIAM, Goddard Spaceflight Center, July 10, 1984.
 
STOKES, JAMES, Johnson Space Center, June 14, 1983.
 
STORY, SCOTT, Ford Aerospace, Johnson Space Center, June 16, 1983.
 
STOTT, RUSSELL, Jet Propulsion Laboratory, May 16, 1984.
 
SULLIVAN, WILLIAM, Johnson Space Center, June 14, 1983.
 
SWEARINGEN, CHARLES, Huntsville, AL, June 21, 1983.
 
TINDALL HOWARD W., telephone interview from Washington, D.C., August 10, 1984.
 
VICK, H.G., Marshall Space Center, June 21, 1983.
 
VINZ, FRANK, Marshall Space Center, June 21, 1983.
 
WALTON, THOMAS S., Kennedy Space Center, July 6, 1983.
 
WILLBANKS, JAMES, IBM, Kennedy Space Center, June 29, 1983.
 
WOODDELL, JOHN, Jet Propulsion Laboratory, May 21, 1984.
 
YARBOROUGH, ROBERT, Kennedy Space Center, July 6, 1983.
 
YOUNG, JOHN, telephone interview from Johnson Spaceflight Center, March 6, 1984.
 
ZIPSE, JOHN, Jet Propulsion Laboratory, 22 May 1984.
 
ZOBRIST, ALBERT, Jet Propulsion Laboratory, May 23, 1984.


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