Sample AGC Code (courtesy
of Gary Neff).
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Introduction (excerpt) This ICD defines and unless otherwise stated, controls the electrical signal interface between the LM Guidance Computer (LGC), including the DSKY, and LM Spacecraft subsystems. Electrical requirements for the interface through which spacecraft prime power is supplied to the LGC are included for reference only. The controlling document for prime power is LIS-390-10002. |
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Fred W. Haise, Jr. |
Abstract The astronaut's role in space transportation is embodied in the Space Shuttle and its associated payload operations. This next-generation spacecraft represents the man-in-space system through the 1980's. A discussion of man's role in the Space Shuttle Program requires some reference to previous manned programs, as many tasks have foundations in the past. Generally, the work astronauts perform can be divided into piloting, experiments/payloads, and "other duties asassigned," which includes such tasks as systems management, extravehicular activity, and housekeeping. The emphasis on man's role will alter somewhat as the Shuttle system progresses from the initial test phase to the operational phase. The Shuttle is designed for automatic guidance, navigation, and control (GN&C), and the need for active piloting will decrease with system maturity. With the shift to onboard autonomous operation, the system management role will expand. Direct tasks with delivery/recovery and laboratory/observatory payloads will continue to expand throughout the program. The Shuttle assures man a role in space through the 1980's. The specific tasks include those involved with previous manned spacecraft as well as some new ones that are primarily associated with payloads. There will be a shift in emphasis regarding the astronaut's tasks as the Shuttle system matures. |
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Robert F. Thompson |
Abstract The objective of the Space Shuttle Program is to achieve an economical space transportation system. This paper provides an introductory review of the considerations Which led to the Government decisions to develop the Space Shuttle. The role of a space transportation system is then considered Within the context of historical developments in the general field of transportation, followed by a review of the Shuttle system, mission profile, payload categories, and payload accommodations which the Shuttle system will provide, and concludes with a forecast of the systems utilization for space science research and payload planning activity. |
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Walter Haeussermann |
Abstract A review of the navigation, guidance, and control system of the Saturn launch vehicle includes the system analysis and design, signal flow diagrams, redundancy, and self-checking features used to obtain extreme reliability for crew safety. The iterative path adaptive guidance mode , featuring flight path optimization, is explained and presented in its computational form. Following the analytical considerations, the main guidance and control components are described. The navigation and control information is obtained inertially by a gyro-servo-stabilized, three-gimbal platform system with three mutually orthogonal pendulous-integrating gyro accelerometers; the single-degree-of-freedom gyros as well as the accelerometers use externally-pressurized gas bearings. Rate gyroscopes provide attitude stabilization; some vehicle configurations require additional accelerometer control to reduce wind loads. The digital computer system serves as the computation, central data, and onboard programming center, which ties in with the ground computer system during the prelaunch checkout of the overall system. The control signals are combined, shaped, attenuated, and amplified by an analog type control computer for engine actuator control. Results from recent launchings of Saturn V vehicles are presented to confirm the adequacy of the navigation, guidance, and control system and its overall performance even under extreme flight perturbations. |
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Requested by the President at Our Meeting on 21 November 1962 |
Author's (Robert C. Seamans) Notes (Excerpt)Memo The discussion with President Kennedy on 1 November revolved around the issue of a $400-million supplemental request for fiscal year 1963. Brainerd Holmes recommended the supplemental as a means for advancing the lunar landing date from 1967 to 1966. Mr. Webb, Dr. Dryden, and I were strongly opposed. In 1961, we had gained approval from Congress for an FY 1962 budget increase from $1.1 billion to $1.8 billion, and Congress had appropriated $3.7 billion for FY 1963. In our view, Congress would balk at a still further increase, and we didn’t feel that NASA could efficiently sustain still further growth. |
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A picture of the Gemini MOCR. Picture of MOCR with personnel identified. This material courtesy of Sy Liebergot. |
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David Scott, NASA Astronaut |
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A collection of documents about the Apollo Guidance Computer. |
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Abstract The documents below, courtesy of Eldon C. Hall, are the specifications and related documents for the AGC's NOR gate (flat pack, dual 3-input NOR version). |
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Abstract The documents below, courtesy of Eldon C. Hall, discuss issues with moving to the flat package for the Block II Apollo Guidance Computer, a dual 3-input NOR microcircuit. |
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Abstract The documents below, courtesy of Eldon C. Hall, discuss an evaluation of the Apollo Guidance Computer and its potential replacement with the Saturn V Launch Vehicle Digital Computer. |
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Abstract |
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George M. Low |
Abstract The flawless performance of the five manned Apollo flights is attributed to reliable hardware; thoroughly planned and executed flight operations; and skilled, superbly trained crews. Major factors contributing to spacecraft reliability are simplicity and redundancy in design; major emphasis on tests; a disciplined system of change control; and closeout of all discrepancies. In the Apollo design, the elimination of complex interfaces between major hardware elements was also an important consideration. The use of man, in flying and operating the spacecraft, evolved during the course of the program, with a tendency to place more reliance on automatic systems; however, the capability for monitoring and manual takeover was always maintained. The spacecraft test effort was increased during the 18 months preceding the first manned flight with emphasis on environmental acceptance testing. This test method screened out a large number of faulty components prior to installation. |
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Don Eyles |
Abstract The Apollo 11 mission succeeded in landing on the moon despite two computer- related problems that affected the Lunar Module during the powered descent. An uncorrected problem in the rendezvous radar interface stole approximately 13% of the computer's duty cycle, resulting in five program alarms and software restarts. In a less well-known problem, caused by erroneous data, the thrust of the LM's descent engine fluctuated wildly because the throttle control algorithm was only marginally stable. The explanation of these problems provides an opportunity to describe the operating system of the Apollo flight computers and the lunar landing guidance software. |
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Eugene M. Emme |
Abstract (excerpt) ... Launching from preceding papers and other examples of turning points in the history of aerospace technology, this paper focuses upon the major elements culminating in mid-l96l with a national decision to broaden and to accelerate the American space program. It examines the influential factors, such as the pace of large rocket booster development, which determined the assessment of the national effort in space. It supports the totality of this assessment of the space program and the portents for the future made in mid-l96l was a strategic decision largely confirmed by subsequent events bringing across-the-board space competence to the United States. Important prerequisites for a sound decision -- technological feasibility, basic program definition, and active development of major components -- were existent before Yuri Gagarin -- first orbited the earth in Vostok I on April 12, 1961. On April 12, such a decision had political feasibility at the highest level as well as with the general public. The Apollo-dramatized request for a national decision by President Kennedy on May 25, endorsed by the Congress and public opinion, required no fundamental alteration of the national goals, governmental structure, or operational basis of the American space program as it had been instituted via the national decision in 1958 after Sputnik. |
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Summary The following interview of Dr. Edgar Cortright was conducted on August 20, 1998, Langley Research Center in Virginia |
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Jack Garman |
Introduction (excerpts) Discussion of the software problem which delayed the first Shuttle orbital flight. On April 10, 1981, about 20 minutes prior to the scheduled launching of the first flight of America's Space Transportation System, astronauts and technicians attempted to initialize the software system which "backs-up" the quad-redundant primary software system ......and could not. In fact, there was no possible way, it turns out, that the BFS (Backup Flight Control System) in the firth onboard computer could have been initialized properly with the PASS (Primary Avionics Software System) already executing in the other four computers. |
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C.M. Lee and A.S. Lyman |
Abstract (excerpt) During the past decade there has been much discussion of the relative merits of manned versus unmanned space activities. With the advent of Shuttle, the distinction between the manned and unmanned missions becomes blurred as they come together into a unified approach for carrying out our total space objectives. Shuttle will be the launch vehicle for transporting almost all automated as well as manned missions into space. As we progressed from Mercury to Gemini to Apollo to Skylab and not to the Apollo/Soyuz Test Project (ASTP) and Shuttle, the role of man has become more important and his capabilities have been increasingly exploited. During this period, we were learning that man could survive and function normally in a space environment, we demonstrated that man could live and effectively work in space, we extended our knowledge of our planet earth through space observation and experimentation, in Apollo, a giant step was taken in exploiting man's capabilities in space, and in ASTP we will lay the groundwork for possible international space rescue and future joint missions. |
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J.J. Rocchio, Bellcomm, Inc. |
Abstract (excerpt) The Launch Vehicle Digital Computer (LVDC) has a modular memory system with a maximum capacity of eight modules. Each module has 16 sectors, for a total of 28 sectors (64 duplexed sectors) in all. At this time, expected reserve capacity in the LVDC memory is about 18% (12.9 sectors duplex) of total capacity for AS 501, and only 11% (6.9 sectors duplex) for AS 504. This is considered insufficient to provide an adequate margin for new requirements and contingencies. |
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F.J. Bailey, Jr., NASA Manned Space
Center |
Introduction The papers presented so far in this session have described specific measures taken in preparing the launch vehicle and spacecraft for Mercury missions. the purpose of the present paper is to review, in somewhat more general terms, some of the more significant lessons learned in the Mercury program, to see where changes or additional measures may be desirable in future programs. The lessons that have been learned fall broadly into two main areas, the first applying to program planning, the second to detailed design. |
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Gerald Sandler, Grumman Aerospace Corporation |
Summary
Over the past decade we have developed the technical and programmatic approaches needed to provide the levels of reliability required for manned space missions. The combination of design, test and control or assurance programs used on Apollo have proven very effective. In the design approach we have learned how to minimize the number of potential single-point failures that could result in mission failure. In test and product assurance areas, screens and controls were established that effectively prevented a. latent defect from filtering through the system and occurring in flight. The cost of these combined efforts, however, have been a large percentage of total program costs. The challenge of this decade, I believe, is how to achieve the same or improved levels of reliability at lower program costs. The area of primary concentration, at this time, should be failures that are "human oriented" rather than "design oriented". Our engineering techniques have gone a long way in reducing the latter problem area. on Apollo half or more of the failures that occurred in the test programs were classified as workmanship, procedural or quality-oriented problems. We have learned how to screen them out by test; what we have to do now is to prevent them from occurring or catch them earlier. In addition, recognizing that failures will always occur in our test programs, the cost challenge is to design units and systems for maintain- ability, rework and proper isolation, so that we can minimize the extent of retesting for adequate confidence. |
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J.C. Graves, The Boeing Company |
Abstract For those unmanned spacecraft that have so far ventured into space beyond the Earth's immediate influence, Earth-based mission control systems have taken the place of the on-board crew. The Lunar Orbiter mission control system is comprised of long-range tracking, telemetry, radio command, and computing equipment plus a team of skilled flight control engineers. After spacecraft separation from the Atlas-Agena launch vehicle, mission control was transferred from the Eastern Test Range to the Space Flight Operations Facility at Pasadena, California, where three crews of flight controllers worked around the clock for 35 days analyzing millions of data samples and originating over 4500 commands to the spacecraft to control its flight path, attitude, and photographic activities. During the flight of Lunar Orbiter I during August 1966, a number of nonstandard events occurred. All of these situation were detected and properly analyzed by the flight control team, and, with the exception of a camera shutter control problem, work-around procedures were developed for all anomalies encountered. A second camera in the spacecraft did, however, successfully provide extensive and informative photographic coverage of the lunar surface. This important contribution to Apollo and to science is surpassed only by the highly successful second flight recently concluded this past December. |
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Richard Phillips and Peter Kachmar |
Abstract (excerpt) The Apollo guidance, control and navigation system was designed by Draper Laboratory (nee the MIT Instrumentation Laboratory) during the mid to late '60's, but was the legacy of a series of earlier studies of Mars photographic reconnaissance missions which had been sponsored by the Air Force Ballistic Missile Division. The development of rocket engines and inertial measurement instruments was basic to turning the dream of poets into the reality of a trip to the moon, but on a narrower scale the development of practical guidance and navigation algorithms was enabled by the development of programmable digital computers and of higher order programming languages. In this paper we will focus in particular on navigation and guidance associated with the rendezvous of the Lunar Module with the Command Module as they orbited the moon. |
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Sherman M. Seltzer
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ABSTRACT The purpose of this paper is to describe the SATURN Launch Vehicle that successfully launched the manned APOLLO spacecraft into Earth orbit and thence onto a trans-lunar trajectory to the moon. It will then describe the SATURN G&C system that enabled this to occur. Using a "building block" approach, the NASA Marshall Space Flight Center (MSFC), under the direction of Wernher von Braun, achieved 33 successful launches out of33 attempts. This included:
This is the only major rocket development program ever to be completed without a catastrophic in-flight failure. The SATURN V, with its 34.7-million N (7.5-million pounds) of thrust in its first stage, lofted 96,000 kg (212,000 lb) of payload into Low Earth Orbit [213 km (115 nautical miles)]. The SATURN 3rd stage then went on to place a 48,500 kg (107,350 lb) payload onto a trans-lunar trajectory. This paper will describe how NASA MSFC was successful in developing and implementing this system. It will describe the SATURN G&C system, including its genesis and associated trade studies. The techniques will be described to show how this feat was accomplished: engineering leadership; the extensive "building block approach; and the integrated design analysis, simulations, and testing. |
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Charles W. Mathews |
Summary The Gemini Program has comprised 12 space flights, 10 of which were manned operations. The information gained is difficult to summarize within a brief paper, but more detailed information has and will continue to be made available to those who have an interest in it. With minor exceptions, the objectives of the program were met, having been expanded well beyond original concepts and examined in considerably more depth than expected. Gemini leaves a legacy of results that, hopefully, will further accelerate man's efforts to explore and utilize the frontier of space. |
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Glynn S. Lunney |
Abstract A significant portion of the Gemini program was devoted to the rendezvous problem. One of the major objectives was to establish a base of operational experience and confidence in the required techniques. In this paper, the planning and flight test cycle is reviewed to provide an outline of the Gemini results. Many various considerations were studied and several of the more important factors are discussed as to their influence on the different choices and subsequent operations. The flight test results are summarized according to technique and performance such as propellant costs, satisfaction of conditions, et cetera. Overall, the conclusion is that the base of experience has been established, the rendezvous sequence is practical, the systems and the management of these systems have been satisfactory in accuracy and performance. Further study and a continued, detailed preparation will be the key to the future uses of rendezvous. |
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Jerome B. Hammack and Walter J. Kapryan |
Introduction It is the intent of this paper to show how the Gemini program has attempted to draw upon and profit from Mercury experience. The Gemini Project has evolved as a NASA space program with its prime mission of providing a flexible space system that will enable us to gain proficiency in manned space flight and to develop new techniques for advanced flights, including rendezvous. To achieve these objectives, we must have a space vehicle with substantially greater capability than the Mercury spacecraft. This increased capability will include provisions for two men, instead of one, as in the Mercury spacecraft and for space missions of up to two weeks' duration. It is the intent of the Gemini Project to build upon the experience gained from Mercury so that most of the energies of the new program can be devoted to the solution of the problems associated with achieving its primary mission objectives and not have to fight its way through a swelter of old problems. |
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Abstract This report describes my successful project to build a working reproduction of the 1964 prototype for the Block I Apollo Guidance Computer. The AGC is the flight computer for the Apollo moon landings, with one unit in the command module and one in the LEM. |
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H. J. Fichtner From PEENEMUNDE to OUTER SPACE |
Introduction (excerpt) Now that space operations have become a reality, it is appropriate to review the accomplishments of the past and to discuss what must be done in the future to insure the operational readiness of our large carrier vehicle systems. Well-planned overall systems engineering is the key to this task, with electrical systems engineering playing a major subsidiary role. When missiles were introduced on a relatively large scale some 25 years ago overall electrical systems engineering did not exist as such, although with theV2 missile the systems approach was being utilized for the first time. In those days the designers of the propulsion system provided for the system's electrical needs by maintaining the required start and cutoff sequence. The designers of the guidance and control system worked their own electrical system and took care of the electrical equipment needed for the checkout and launch operations. |
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Alfred B. Eickmeier |
Introduction (excerpt): The recent advent of space exploration and manned space flight has provided aerospace technologists and engineers with many challenging problems in instrumentation development and application Capabilities for accurate determination of inflight spacecraft performance and external environmental parameters have steadily increased from early missile flights, which required only a few relatively simple measurements, to present-day programs such as Apollo, which require in excess of several hundred independent and individual measurements. |
Chester A. Vaughan |
Abstract: Descriptions of the reaction control systems for the Apollo command module, service module, and lunar module are presented. Major problems encountered during the development and qualification of the engines for these systems are discussed. These systems are pressure fed, bipropellant, hypergolic propulsion systems utilizing nitrogen tetroxide as the oxidizer and the hydrazine group of fuels. A total of 44 reaction control system engines are installed in the three modules. The Apollo reaction control system must satisfy many unique environmental requirements ranging from zero-gravity propellant feed to operation with the reaction control system engine in a gravitational field firing vertical up. Operational requirements range from short on-off to long on-off firing times. Total impulse requirements from a single firing range from 0.4 to 50 000 pound-seconds. Ten thousand firings may be required of some engines. Three Apollo command module and service module flights and one lunar module flight have been made. In each flight, the reaction control system performed its required functions successfully. |
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SP-257: National Aeronautics and Space Meeting |
Contents:
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Rolf W. Lanzkron and William C. Fischer |
Abstract (excerpt) The basic criteria for checkout of manned vehicles can be stated as follows, quoted from the "Apollo Checkout Criteria":
These statements summarize the basic Apollo Checkout Criteria. |
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from Wikipedia, the free encyclopedia |
Overview The Apollo Guidance Computer (AGC) was the first recognizably modern embedded system. It was developed for the Apollo program by the MIT Instrumentation Laboratory under Charles Stark Draper, with hardware design led by Eldon C. Hall (see References). Based upon MIT documents, early architectural work seems to come from J.H. Laning Jr., Albert Hopkins, Ramon Alonso, and Hugh Blair-Smith. The actual flight hardware was fabricated by Raytheon, whose Herb Thaler was also on the architectural team. |
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All publications: http://history.nasa.gov/series95.html Online publications: http://history.nasa.gov/on-line.html |
11th Annual Naval Aviation Symposium May 18, 1997 |
Panel of Apollo Astronauts:
Moderator:
Introductions:
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Fred Martin, MIT/IL |
Introduction 25 years ago it happened, the first Lunar Landing, Apollo 11 - July 20,1969. It was an exciting, exhilarating time of total focus and dedication. Current and alumni Intermetrics employees were intimately involved with the project since its inception in 1960 (John Miller, Jim Miller, Ed Copps, Jim Flanders, Dan Lickly, Joe Saponaro, Bill Widnall, John Green, Alex Kosmala, Ray Morth, Steve Copps and me, Fred Martin). The most memorable part of the flight for me, aside from the landing and the moonwalk itself, was the descent from lunar orbit to the surface. I'd like to present a personal remembrance and perspective. |
| KennedySpeech.htm |
First, I believe that this nation should commit itself to achieving the goal, before this decade is out, of landing a man on the moon and returning him safely to the earth. No single space project in this period will be more impressive to mankind, or more important for the long-range exploration of space; and none will be so difficult or expensive to accomplish. |
http://space.systems.org/oralhist.htm
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Title, Author, and Reference |
Abstract |
J. B. Friedenberg, J.J. Landers, and P. Marcellos |
Abstract The LEM Program at RCA pp. 16-20 A brief description of the wide range of reliability tasks implemented under the Lunar Excursion Module (LEM) reliability program illustrates the vital role of reliability in all phases of the program, from conceptual design of a circuit to delivery as flight hardware. Analytical techniques and hardware aspects of reliability are discussed. |
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P. 5. Schoonmaker |
Abstract This paper describes a study of centralized vs. distributed processing approaches to the design and integration of a new Space Shuttle Orbiter subsystem -- the Power Extension Package (PEP), a 25-kw solar array. The objective of this study was to determine the "best" a l location of PEP monitoring and control functions between the existing Orbiter Systems Management (SM) computer and an autonomous PEP processor. Four candidate functional configurations were defined, and a subjective, life-cycle assessment of the re1ative merits o f these candidates was performed by the study team. We concluded that the optimum configuration will (a) include substantial processing "intelligence" in the PEP processor, and (b) make use of SM computer "standard services". |
W. T. Chow Proceedings of the Tenth Space Congress |
Abstract: The development of airborne digital computer has been greatly influenced by rapid technological advances. This paper provides an overview of the present status and the direction of further evolution. It discusses the changes that are taking place in the areas of hardware, software, and computer organization; and suggests a number of approaches towards a broadened usage of airborne computer to take advantage of its increasing capability and decreasing cost. |
Skylab Attitude Control System T. R. Coon, J. E. Irby |
Abstract |
Matt Bille (AIAA Senior Member) Erika Lishock Paper AIAA 2002-0313 |
ABSTRACT In October 1957, the first race into space ended with the launch of the Soviet Union's Sputnik 1. As America's official satellite program, Vanguard, struggled through technical difficulties, Wernher von Braun and his Army Ballistic Missile Agency team successfully pressed for permission to launch their own satellite. The result was Explorer 1, which, despite its hurried construction and diminutive size, restored American prestige while making a major scientific discovery. This paper draws on recent scholarship, declassified documents, and new interviews conducted by the authors to clarify the technology and the politics surrounding America's first satellite. The genesis of Explorer 1 involved science, interservice rivalry, Cold War politics, and some truly ingenious engineering. In the modern era, where satellite programs may cost billions of dollars and take decades to carry out, the achievements of the tiny Explorer spacecraft convey lessons which should be preserved. |
Matt Bille (AIAA Senior Member) Erika Lishock Paper AIAA 2002-0314 |
ABSTRACT In the late 1950s, the entire world became aware of the successes and failures of the first Earth satellite projects - Sputnik, Explorer, and Vanguard. Only a handful of people knew there were actually four such projects, not three. In the California desert, Navy engineers and scientists in 1958 were engaged in a classified crash program to develop the world's first aircraft-launched satellite. Against an impossible deadline, with limited resources, they may just possibly have succeeded. This paper examines the now-declassified story of the "NOTSNIK" satellite booster, a five-stage improvisation using a concept decades ahead of its time. In the frantic days after Sputnik, personnel at the Naval Ordnance Test Station in China Lake conceived a project to put rapid, all-aspect access to orbit in the hands of naval forces worldwide. From approval to orbit, they had four months to design and build a complete space system. Their one-kilogram test satellites may or may not have made orbit, but the project stands as a fascinating demonstration of ingenuity, determination, and imagination in the first year of the Space Race. |
"Some Aspects of the Logical Design of a Control Computer: A Case Study" R.L. Alonso, H. Blair-Smith, and A.L. Hopkins, Instrumentation Laboratory, MIT,
Cambridge, Mass. |
Some logical aspects of a digital
computer for a space vehicle are described, and the evolution of its logic design is
traced. The intended application and the characteristics of the computer's ancestry
form a framework for the design, which is filled in by accumulation of the many decisions
made by its designers. This paper deals with the choice of word length, number
system, instruction set, memory addressing, and problems of multiple precision arithmetic. The computer is a parallel, single address machine with more than 10,000 words of 16 bits. Such a short word length yields advantages of efficient storage and speed, but at a cost of logical complexity in connection with addressing, instruction selection, and multiple-precision arithmetic. |
"Primary Processor and Data Storage Equipment for the Orbiting Astronomical Observatory" Thomas B. Lewis, IBM Corporation, Space Guidance Center, Owego, NY. |
Telescopes in space will soon permit
astronomers to observe the heavens in more detail than ever before. The Orbiting
Astronomical Observatory (OAO) is a space vehicle designed to place these telescopes in
orbit beyond the earth's atmosphere and to telemeter the collected data back to earth. To aid the orbiting observatory in the fulfillment of its scientific mission, a low-power, long-life, high-density command and memory system has been designed and is currently undergoing qualification testing. The digital command storage and processing element will permit reprogramming of spacecraft orientation and astronomical experiments on each orbit, even when the satellite is not in contact with the ground, while the core memory element will permit storage of experiment data for subsequent transmission to the ground. In the following paper, the functional design of the satellite command and memory system is discussed in detail. In addition, the power conservation methods, reliability design techniques and environmental performance considerations which influenced the design of this equipment are reviewed. |
"Mission Influences on Advanced Computers" Gene A. Vacca, NASA Office of Advanced Research and Technology, Philip L. Phipps,
UNIVAC Div., Sperry Rand Corp., and Thomas E. Burke, NASA Electronics Research Center |
Future spaceflight and advanced SST and Jumbo Jet operations help define mainstream trends in computers and promote design concepts. |
"Flight Computer Hardware Trends" Ramon L. Alonso, MIT, and Glenn C. Randa, IBM Corp. |
Increasingly powerful integrated-circuit technology - promising new flight programs, controls, and displays - now challenges the foresight of the system designers. |
| Proceedings - Conference on Spaceborne Computer Engineering Anaheim, California |
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Dr. Joseph F. Shea, Deputy Director of Manned Space Flight (for Systems), NASA |
Summary The performance of complex manned and unmanned space missions requires considerably sophisticated on-board computers to perform a variety of tasks. This paper examines, in some detail, the functional and environmental requirements for such units. |
| "Two Approaches to the Design of Spacecraft Data Handling System" R. C. Baron, R. W. Waller, Computer Control Company, Inc. |
The Systems described in this paper were developed by Computer Control Company for the Jet Propulsion Laboratory (NASA) for use in the Mariner Interplanetary exploration program. On board the Mariner Spacecraft are a number of instruments which perform experiments designed to further man's knowledge concerning the scientific properties of the planets and deep space. Two spacecraft scientific data handling and control systems were designed for this program and are discussed here. Both systems are similar in that they act as a buffer between all scientific experiments and telemetry. They differ substantially in their implementation of this function. One system, the Science Data Conditioning System (SDCS) is a real time, fixed sampling sequence and control system. The other, the Science Data Automation System (SDAS), is a more versatile programming system which uses standard digital computer techniques to provide buffer data storage, variable experiment sampling sequences, and modified programs during the course of a mission. The hardware used to build these two systems is described and the logic, circuit, and packaging marriage problems are discussed. |
| "A Multiaperture Digital Memory Having Nondestructive Sensing" Proceedings - Conference on Spaceborne Computer Engineering |
A ferrite sheet memory featuring nondestructive read
operation and a short read cycle time has been developed. The nondestructive read is
accomplished by sampling the complex flux pattern in a selected bit position on the
ferrite sheets. The use of the ferrite sheet has resulted in considerable saving in
wiring complexity as compared to previous systems having nondestructive read ability. A small prototype memory was built, and has achieved read cycle times of one microsecond, information access times of 0.3 microseconds, and a write time of 4 microseconds. The currents involved are easily obtainable with transistor drivers. |
| "Logic Organization of the UNIVAC ADD-1000 Aerospace Computer" D.C. Morse, B.J. Jansen, and R.P. Blixt, UNIVAC Division of Sperry Rand Corporation |
This report emphasizes the logical design of the ADD-1000
which is the first airborne computer to utilize a thin-film magnetic memory. The computer operates in the binary, parallel mode employing two's complement fractional arithmetic. The logic design is based on the use of a random-access moderate speed memory. For example, assigned memory addresses in the scratch-pad memory are used in place of the several arithmetic registers such as A, Q, and X, and counters, such as velocity and incremental accumulators required by conventional computers. A highly flexible repertoire of over 950 useful instructions is achieved by means of a sequential phase-field method of execution described in detail later. The inherent flexibility of the instruction logic provides an effective saving in program memory capacity of more than fifty per cent over single address drum computers, and a smaller but significant saving over indirectly addressed computers, that is, computers without extensions or switching. Other special features found in the computer include interrupt features; variable-length multiply and divide operations; capability to increment of decrement the content of any scratch-pad memory location without modifying the content of the accumulator; double-word-length shift instructions; 16 input and 16 output addressable channels (with an almost unlimited umber of direct inputs available); priority options; and on-line self-loading of program instructions and constants. The computer represents a signifant achievement in meeting the requirement for a data processor which is small, light, rugged, and low in power consumption, while possessing at the same time the qualities of speed, large modular storage capacity, and high reliability. Note: This "low power" machine had a peak power consumption of 262 watts peak, with performance measured in 10's of kips. Along with the reference to the drum memory in the introduction, above, the I/O section of the computer, along with being tailored for missle control, had an interface to a paper tape reader and punch. |
| "The Arma Micro Computer for Space Applications" E. Keonjian, Inertial Guidance Department, J. Marx, Arma Division, American Bosch Arma
Corporation |
The Arma Micro Computer is a serial binary, stored program
computer, capable of calculating at the rate of 36000 operations on a 22 bit word per
second. Additoin or subtraction requires 27 x 10-6 seconds, including
access to memory; multiplication requires 135 x 10-6 seconds; division requires
324 x 10-6 seconds; square root, depending on the precision required, up to 584
x 10-6 seconds. Although it is a serial machine, computation rates are
enhanced by access to memory in parallel while multiplication, division and square root
processes in quasi-parallel, using unusual algorithms for minimization of hardware.
In addition, higher effective speed is obtained because the operations add or subtract,
and multiply or divide or square root may be processed simultaneously. The Micro Computer is designed, primarily, for versatility in handling such problems as guidance, on-board data evaluation and monitoring, system checkout and information telemetering for a missle or spacecraft. It is the third in three generations of airborne computers designed and built by Arm Division of American Bosch Arma Corporation. |
| "The D210 Magnetic Computer" Eugene T. Walendziewicz, Burroughs Corporation |
The Burroughs D210 is a general-purpose, parallel,
synchronous, digital computer using predominantly magnetic circuit techniques. It is
particularly well suited for use as a control element in applications which require
operation in stressed environments, which require a computer of high reliability, and
which call for equipment of small size, low weight, and low power consumption. The
D210 is capable of performing the computations required in missle and satellite systems
for guidance, control, and system checkout. The D210 overcomes the traditional speed limitations of magnetic systems, without resorting to the use of unconventional components, by means of a new organization. Its unique logic permits relatively fast operations (30-microseconds add, for example) with a clock of only 100 kc, and requires minimal power consumption and a fraction of the compnents ordinarily required. Power consumption is proportional to the computation rate, with essentially no standby power required. Under program control, the clock rate can be varied to match the real-time needs of each task, thus minimizing drain on the primary power supply and extending component life through reduced dissipation. With these characteristics, it is reasonable to predict an unattended computer life expectancy of up to several years for many applications. Note: For those travelling here from the programmable logic pages, the logic used in this computer may be interesting. The core-rope memory4 is described first and then a detailed explanation of their logic implementation follows. The core-rope was used on the AGC, for example, for read only memories and had essentially a fixed AND plane and a programmable OR plane. The programming of the OR plane was accomplished by threading or not threading a sense wire through the selected core, with 2n cores, each implementing a fixed AND function of all of the inputs. The logic elements in the D210 were implemented by providing programmable AND and OR planes. First, each input was complemented, making both senses of each input available. Then, for each term involved in the AND function, either the true or complement was threaded through a single a core (it actually decoded when all inputs were a logic '0'). A sense line was then wound through all of the desired AND cores to finish implementation of the logic equation. This is quite similar to a PLA. Since large numbers of wires could be threaded through a core, the gates had a very high fan in to go along with their high fan out. 4R. Alonso and J.H. Laning, Jr., "Design Principles for a General Control Computer"(R-276, Instrumentatin Laboratory, MIT, April, 1960). |
| "HCM-202 Thin Film Computer" M. M. Dalton, Hughes Aircraft Company |
The HCM 202 is the latest in a family of high performance
parallel computers for aerospace applications. There are two major features which
distinguish the HCM 202 from other aerospace digital computers. First of all, the
HCM 202 has been designed to fulfill the exacting requirements of a wide variety of
aerospace applications with a minimum of redesign effort. This flexible or modular
design approach has been necessitated by an expanding market for small quantities of
digital computers to fulfill the specific requirements of advanced aerospace
systems. The second unique feature of the HCM 202 is its advanced thin film
construction. The basic objectives of this thin film microelectronic fabrication
method has been to greatly improve the reliability of the digital computer and to reduce
the fabrication cost. A further advantage of the construction technique used in the
HCM 202 is a unique and highly flexible interconnection technique which has solved one of
the major stumbling blocks to effective thin film construction of complex digital
computers. Note: For those travelling here from the programmable logic pages, the interconnection technique used in this computer may be interesting. On the back of the wafer, there's a two level grid of metal interconnect put down. "By the simple selective etching of the upper or lower interconnection layers, virtually any given wiring configuration can be achieved. ... the unique arrangement required for each circuit wafer need not be applied ... is very nearly through its fabrication cycle." This sounds similar to the more recent Chip Express devices., |
| "Radiation Environment at High Orbital Altitudes" Peter W. Higgins, Joseph C. Lill, and Timothy T. White, Space Physics Division, Science
and Applications Directorate, NASA Manned Spacecraft Center. |
The Gemini X and XI space flights were highlighted by
high-altitude apogees achieved by firing the Primary Propulsion System of the Gemini Agena
Target Vehicle. In both flights, the docked spacecraft target-vehicle combinations
were carried much higher into the Van Allen trapped radiation belt than ever before in
manned space flight. This paper deals with the radiation environment at these altitudes and the effect of the environment on the two missions. An attempt will be made to describe the premission radiation planning for the flights, the inflight radiation measurements, the results of the postflight data analysis, and the preliminary conclusions. |
Carlos S. Warren1, Joesph C. Lill2, Robert B. Richmond3, and William G. Davis4 NASA Manned Spacecraft Center, Houston, Texas Journal of Spacecraft, Vol. 5, No. 2., February 1968, pp. 207-210 |
Abstract U.S. astronauts are equipped with radiation-dose recording instrumentation. This paper describes the dosimetry used on Gemini and that designed for use on Apollo. Radiation doses received by Gemini crews varied between less than 10 mrad on the Gemini VIII mission (Neil A. Armstrong and David R. Scott) and 779 mrad on the Gemini X mission (Michael Collins). Particle spectrometers were flown on the Gemini IV and VII missions in order to compare dose calculations to measurements. Radiation instrumentation for Apollo consists of a particle spectrometer, rate-meters, integrating dosimeters, and passive dosimeters. The rationale for each instrument is discussed. Calculated doses in the Apollo vehicle are presented for intense events in the last solar cycle. |
| "Core Rope Memory" Computer Design |
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"Computer Memories - A Survey of the State-of-the-Art" Jan A. Rajchman, RCA Labs., Princeton, N.J. |
Summary - Computer memory developments of the last decade, the present state, and efforts for improvements are surveyed. The following topics are included: principles of storage and selection of random-access memories; principles and engineering considerations of current-coincident-driven core memories; magnetic decoding and load-sharing switches; word-organized one-core and two-core-per-bit memories; fast and impulse switching; transfluxor memories; non-destructive read-out memories; ferrite apertured plates; twistors; fixed read-only memories; thin magnetic film memories - dots, sheets, coated wires and rods; present operational memories typically with capacities of 10E5 and 10E6 bits and read-write cycles of 2 to 15 usec; likelihood of the order of 100-nsec read-write cycle times attainable with ferrite and thin film memories; consideration relating to large capacities; ferroelectric memories attempts; cryoelectric superconductive memories - principle, superconductive films, Crowe cells, continuous sheets, systems, and the outlook for large capacities; tunnel diode memories which promise a read-write cycle of the order of 10 nsec; and outlook for content addressable memories. |
| Saturn V Launch Vehicle Digital Computer and Data Adapter M. Dickinson, J. Jackson, and G. Randa, IBM Space Guidance Center |
This paper describes the IBM Space Guidance Center's part in
the Saturn V Program and the digital computer and data adapter being developed for the
Saturn V booster. This work is being performed under contract to NASA under
direction of the Marshall Space Flight Center, Huntsville, Alabama. The computer and data adapter are located in the Saturn V Instrument Unit and integrated into the total guidance system of the booster. The computer interfaces only with the data adapter, which in turn presents the interface to the rest of the system. Basically, during boost guidance, the computer evaluates in-flight changes in booster speed and position derived from an inertial platform and develops signals to control the rocket engines so as to keep the booster on course. The data adapter takes analog inputs from sensors and converts them to digital form of the computer; it also takes the computer digital outputs, converts some of them to analog form, and sends corrections to the appropriate controls. |
| "Testing the Man-Rated Launch Vehicle" Francis X. Carey Proceedings of the Third Space Congress 1966, pp. 332-341 |
Although manned space flight is still in its infancy, testing
of launch vehicles has progressed to a high degree of sophistication. As of December 1965, the Martin-built Gemini launch vehicle has launched seven Gemini spacecraft successfully out of seven attempts. This remarkable record was made possible by two facts:
This paper briefly describes the Gemini launch vehicle noting the major differences between it and the Tital II and discusses the test program. It is not proposed that this is the only method of testing a man-rated launch vehicle; however, it is a successful one. The Gemini launch vehicle is a basic Air Force Tital II which has been modified in certain areas to achieve man-rating. |
|
A.J. Kullas |
Abstract The primary purpose of this note is to change the approach to the design of launch vehicles destined to carry man into space. The proposal consists of adding to today's state of the art the interconnection of systems coupled with much greater utilization of the astronaut's judgment and more extensive systems flight test in order to get the most out of the man-machine combination. A brief history of actions taken to produce today's man-rated booster is offered to show that a uniform approach does not exist. A basic definition of man-rating consistent with the previous intent is offered: A booster is considered as man-rated when its design permits an astronaut alternate equipment choices and alternate capabilities through participation in the propulsion and guidance control functions and, in addition, in the course of the booster flight test development, it is as deliberately as possible exposed to the critical design conditions to assure its capability to perform adequately in the real mission environment. The actions involved in "man-rating" Atlas Mercury, Titan Gemini, Saturn, and Titan III can be classified into six general headings: 1) motivation of engineers and technicians to be more careful in their work, 2) hardware changes for increased booster and spacecraft reliability, 3) hardware changes to enhance mission success, 4) hardware changes for astronaut personal safety, 5) special handling and selection of parts, and 6) astronaut training. The specific actions applied to each of the boosters is markedly different. No fundamental criteria form the basis for all of the actions taken. Each is considered as man-rated in its own inimitable way. |
Edward H. Bersoff Margaret Elaine Hope IEEE Transactions on Aerospace and Electronic Systems |
Abstract This paper discusses one area of research being carried out at the NASA/Electronics Research Center in strapdown guidance technology. In particular, the task of determining the characteristics of the onboard computer is examined. Strapdown calculations impose unique constraints on the computational requirements of the flight computer. In addition, this computer should be suitable for prolonged unmanned missions, which involves system reliability. A description of this ideal system is followed by a description of the first implementation of this approach, the modular computer breadboard. |
Samuel W. Matthews AIAA Aerospace Computer Systems Conference
|
AbstractThe Improved
Centaur computer assimilates hardware functions of the Centaur vehicle that can be
performed by a digital computer. The resulting Centaur electronics module embodies a
computer-controlled guidance and flight control system with lower variable cost, increased
reliability, and the flexibility to accommodate without hardware modifications most
vehicle and payload configurations. Functional tasks currently assigned to the computer
are navigation, guidance, flight attitude control, vehicle sequencing, propellant
utilization, and telemetry format control of computer parameters.
To obtain a manageable system for implementing the computer's tasks, the precepts of large-scale computer systems were adapted to produce a state-of-the-art aerospace software system. The operating system consists of the task scheduling algorithm, task table, re-entrant storage techniques, task/executive communication routines, and hardware interrupt processors. Individual functional tasks are classified and structured as modules, which can be easily tested and replaced to accommodate mission-peculiar requirements. The real-time, multiprogram, execution control consists of a combination of hardware priority interrupts and a real-time software technique that extends indefinitely the priority interrupt structure under executive program control. The system provides flexibility, permits any degreee of modularity, permits individual functional tasks to be coded independently without detailed timing considerations, and permits independent control of preflight tasks by a ground computer which overlays a portion of airborne computer memory. These advantages result In reduced programming and checkout costs. |
Title, Author, and Reference |
Abstract |
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SP-287 |
CONTENTS
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EP-76 |
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1972 |
Introduction (excerpt) One of the valuable byproducts of the U S. space program is the body of knowledge concerning management of large complex development project activities. The brief span of years since the formation of NASA has witnessed the rapid evolution of a variety of systems and techniques for directing the combined efforts of thousands of individuals cooperating in closeknit programs in which Government, university, and private industry play mutually reinforcing roles. Many of the major learning experiences, such as those in the Apollo management system, have been applied to other activities within NASA. There has been only limited effort, however, to distill the generalized management experience gained in other NASA projects for application outside the space agency itself. Note: NASA commissioned the National Academy of Public Administration to undertake this study to look at its innovative management techniques on these complex technological projects. |
James E. Tomayko The NASA History Series |
Foreword (excerpt) This history of the F-8 Digital Fly-By-Wire Project at NASA’s Dryden Flight Research Center by Dr. James E. Tomayko of Carnegie Mellon University is important for a number of reasons. Not the least of these is the significance of the program itself. In 1972 the F-8C aircraft used in the program became the first digital fly-by-wire aircraft to operate without a mechanical backup system. This fact was important in giving industry the confidence to develop its own digital systems, since flown on military aircraft such as the F-18, F-16, F-117, B-2, and F-22, as well as commercial airliners like the Boeing 777. Flying without a mechanical back-up system was also important in ensuring that the researchers at Dryden were working on the right problems. The F-8 Digital Fly-By-Wire Project made two significant contributions to the new technology: (1) a solid design base of techniques that work and those that do not, and (2) credible evidence of good flying qualities and the ability of such a system to tolerate real faults and to continue operation without degradation. The narrative of this study captures the intensity of the program in successfully resolving the numerous design challenges and management problems that were encountered. This, in turn, laid the groundwork for leading, not only the U.S., but to a great extent the entire world’s aeronautics community into the new era of digital fly-by-wire flight controls. The book also captures the essence of what NASA is chartered to do—develop and transfer major technologies that will keep the U.S. in a world leadership role as the major supplier of commercial aviation, military, and aerospace vehicles and products. The F-8 project is an example of how advanced technology developed in support of the agency’s space program, in this case the Apollo endeavor, can be successfully transferred to also address the agency’s aeronautics research and development goals, greatly multiplying payoff on taxpayer investments and resources. It is truly an example of what NASA does best. |
NASA-TM-74736 |
In the course of conducting research on the problem of space rendezvous and on various aspects of manned space missions, Langley Research Center has evolved what is believed to be a particularly appealing scheme for performing the manned lunar landing mission. The key to the mission is the use of lunar rendezvous, which greatly reduces the size of the booster needed at the earth. More definitely the mission may be described essentially as follows: A manned exploration vehicle is considered on its way to the moon. On approach, this vehicle is decelerated into a low-altitude circular orbit about the moon. From this orbit a lunar lander descends to the moon surface, leaving the return vehicle in orbit. After exploration the lunar lander ascends for rendezvous with the return vehicle. The return vehicle is then boosted into a return trajectory to the earth, leaving the lander behind. The significant advantage brought out by this procedure is the marked reduction in escape weight required; the reduction is, of course, a direct reflection of the reduced energy requirements brought about by leaving a sizable mass in lunar orbit, in this case, the return capsule and return propulsion system. This report has been prepared by members of the Langley Research Center to indicate the research that has been conducted, and what a complete manned lunar landing mission using this system would entail. For further reference, main contacts are John D. Bird, Arthur W. V oge1ey, or John C. Houbolt. J.C.H. |
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Preface The Apollo 13 accident, which aborted man's third mission to explore the surface of the Moon, is a harsh reminder of the immense difficulty of this undertaking. The total Apollo system of ground complexes, launch vehicle, and spacecraft constitutes the most ambitious and demanding engineering development ever undertaken by man. For these missions to succeed, both men and equipment must perform to near perfection. That this system has already resulted in two successful lunar surface explorations is a tribute to those men and women who conceived, designed, built, and flew it. Perfection is not only difficult to achieve, but difficult to maintain. The imperfection in Apollo 13 constituted a near disaster, averted only by outstanding performance on the part of the crew and the ground control team which supported them. The Apollo 13 Review Board was charged with the responsibilities of reviewing the circumstances surrounding the accident, of establishing the probable causes of the accident, of assessing the effectiveness of flight recovery actions, of reporting these findings, and of developing recommendations for corrective or other actions. The Board has made every effort to carry out its assignment in a thorough, objective, and impartial manner. In doing so, the Board made effective use of the failure analyses and corrective action studies carried out by the Manned Spacecraft Center and was very impressed with the dedication and objectivity of this effort. The Board feels that the nature of the Apollo 13 equipment failure holds important lessons which, when applied to future missions, will contribute to the safety and effectiveness of manned space flight. |
(audio) |
May 25, 1961 First, I believe that this nation should commit itself to achieving the goal, before this decade is out, of landing a man on the moon and returning him safely to the earth. No single space project in this period will be more impressive to mankind, or more important for the long-range exploration of space; and none will be so difficult or expensive to accomplish. (Full Text) (Kennedy Library) |
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September 21, 1962 |
JFK at Rice University |
| jsc_mirror | A large number of history documents. A mirror of the public JSC pages. |
| sp4206 |
A Technological History of the Apollo/Saturn Launch Vehicles |
| sp4213 |
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Apollo Training April 1, 1966 |
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AGC4 Basic Training Manual, Vol. I of II Document No. E-2052 |
This manual contains a concise description of
that which a computer programmer should know about the Apollo Guidance and Navigation
Programming System to be useful. That is we answer the following questions: What are
the pertinent machine characteristics? What programming languages and conventions
exist for my use? What systems subroutines may I rely on? How do I communicate
with the system subroutines which I need? This manual does not concern itself with
the Mission Programming System or that which an engineer or mathematician must know to
adequately program a phase of the mission after he has an adequate knowledge of the
system. This manual attempts to be thorough while brief. It does not try to exhaust all there is to know about a subject nor does it try to make the reader an expert on any subject. It is designed so that someone fairly new to the subject may acquire a practical understanding of it within the shortest time. Whenever a detailed and complete understanding is required the reader should consult the program listing and/or other technical documents. This manual is divided into four sections. Section I discusses the AGC4 and how to program it in Assembly Language. Section II describes the Interpreter and how to program in Interpretive Language. Section III describes the System Software subroutines and how to interact with them. Section IV contains an outline and suggestions for teaching sections I-III. Each section has a table of contents. |
The Apollo Guidance Computer Document No. R-416 |
The general logical structure of the on-board Apollo Guidance Computer is presented, and the developments of fixed and erasable memory are described. Particular attention is given to the methods of input and output. |
Computers in Spaceflight: The NASA Experience James E. Tomayko, Wichita State University, NASA Contractor Report CR-182505, National Aeronautics and Space Administration, Scientific and Technical Information Division, 1988, 417 pages. |
Notes: This book examines the computer systems used in actual spaceflight or in close support of it. Each chapter deals with either a specific program, such as Gemini or Apollo onboard computers, or a closely related set of systems, such as launch processing or mission control. Also published in Volume 18 of the "Encyclopedia of Computer Science and Engineering", as published by Marcel Dekker, New York. All references can be found in the Special Collections of Ablah Library, Wichita State University, Wichita, Kansas. |
Astrionics System Handbook: Saturn Launch Vehicle International Business Machines Corp., NASA-CR-102371 (MSFC-IV-4-401-1, IBM-68-996-0002), International Business Machines Corp., November 1968, 399 pages |
Notes: This describes the Saturn V avionics and computer systems. |
| Apollo Lunar Descent and Ascent Trajectories Floyd V. Bennet |
A description of the premission planning, real-time situation, and postflight analysis for the lunar descent and ascent phases of the Apollo 11 mission, the first manned lunar landing, is given. Actual flight results are shown to be in agreement with premission planning. Based on Apollo 11 postflight analysis, a navigation correction capability was provided for Apollo 12. A preliminary postflight summary of the descent for Apollo 12, the first pinpoint landing, is also included. |
| NASA Space Vehicle Design
Criteria Spaceborne Digital Computer Systems NASA SP-8070 W. Hoffman, Aerospace Systems , Inc. |
As space vehicle missions have become more complex, the use of onboard
digital computers has become more prevelant. The functions which these computers are
assigned to perform are also expanding in number and magnitude. As a result, the
problem of specifying and designing digital computers for space vehicles has increased in
complexity. Although most spaceborne digital computers are of the type often referred to as "general purpose," they have been in fact special-purpose machines in that a particular choice of design must reflect the requirements of the particular mission application. Thus, the program manager must be aware of the capabilities and limitations of spaceborne computer systems and the design tradeoffs which might affect his application. The flight performance of spaceborne digital computer systems has generally been successfull. However, a number of recurring problems have been experienced during the design, development, and testing of these machines. Previous systems have been very costly, have required major redesigns, and have caused significant schedule delays. Most difficulties have resulted from 1) lack of adequate capacity and flexibility to accommodate expanded requirements, 2) poorly defined subsystem and interface specifications, 3) the impact on software of changing mission requirements, and 4) reliability demands. This report is divided into three major sections:
It also includes an excellent set of references. |
A Perspective on the Human-Rating Process of U.S. Spacecraft: Both Past and Present NASA Special Publication 6104 B. Zupp, Editor February, 1995 |
Historically, the methods of implementing human-rating vary as a
function of program, across the systems and subsystems that are components of a program or
project, and sometimes across mission phases within a program. Although details of
specific implementations have varied, the top-level, fundamental process
has remained constant. That invariant process is as follows:
As used here, human-rating implementation refers to a specific approach to ensuring that the space system is human-rated. For example, capsule separation and jettison is an implementation approach that provides the required level of human safety during launch. However, an abort system carries risks of malfunction which can affect otherwise normal missions. Quad-redundancy and high reliability are other implementation approaches that can satisfy a required level of human safety. Similarly, as used here, the human-rating process is that set of procedures and methods that not only estimates and evaluates the combined components of human-rating along with cost, schedule, risk, benefit, and performance, but also maintains an active consistency of decisions. 1The human rating process for Mercury, Gemini, and Apollo Programs was centered on human safety. The Skylab and Shuttle Programs added to this an emphasis on human performance and health management. |
S.M.F. Fund Paper No. FF-29 R. Alonso and J.H. Laning, Jr. April, 1960 A condensed version of this paper was presented at the Institute of Aeronautical Sciences National Specialists Meeting on Guidance of Aerospace Behicles, May 25,27, 1960. This report was prepared under Project DSR 52-156 sponsored by the Ballistic Missle Division of the Air Research and Development Command through USAF Contract AF04(647)-303 and Project DSR 53-138, Division of Sponsored Research, Massachusetts Institute of Technology, sponsored by the Bureau of Ordnance, Department of the Navy, under Contract NOrd 17366. |
Abstract A set of techniques is described which permits the design of computers particularly well suited for outer space and other airborne control applications. These techniques are unified by reference to a representative computer. Some of the properties of the computer are: variable speed, power consumption proportional to speed, relatively few transistors, relatively large storage for program and constants, and parallel transfer of words. Certain features of the input system permit automatic incrementing of counters and automatic interruption of normal computer processes upon receipt of inputs. The program and constants are stored in a wired-in form of memory which permits unusually high bit densities. Table of Contents Introduction |
Proceedings of an Oral History Workshop Monographs in Aerospace History Conducted July 21, 1989. Participants:
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Foreword In a spring 1999 poll of opinion leaders sponsored by leading news organizations in the United States, the 100 most significant events of the 20th century were ranked. The Moon landing was a very close second to the splitting of the atom and its use during World War II. "It was agonizing," CNN anchor and senior correspondent Judy Woodruff said of the selection process. Probably, historian Arthur M. Schlesinger, Jr., best summarized the position of a large number of individuals polled. "the one thing for which this century will be remembered 500 years from now was: This was the century when we began the exploration of space." He noted that Project Apollo gave many a sense of infinite potential. "People always say: If we could land on the Moon, we can do anything," said Maria Elena Salinas, co-anchor at Miami-based Spanish-language cable television Univision, who also made it her first choice. End excerpt. Roger D. Launius |
Office of Manned Space Flight |
Table of Contents
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Title, Author, and Reference |
Notes |
|
Michael H. Gorn |
Contents Introduction
Epilogue |
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The NASA History Series |
Contents
Foreword: Willis H. Shapley
Appendix A: Selected Documents |
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Edited by Roger D. Launius and Howard E. McCurdy University of Illinois Press |
Contents
Introduction: The Imperial Presidency in the History of Space Exploration, Roger D. Launius and Howard E. McCurdy
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