Shuttle System Research Articles

Analyzing spacecraft configurations through specialization and default reasoning

For an “intelligent” system to describe a real-world situation using as few statements as possible, it is necessary to make inferences based on observed data and to incorporate general knowledge of the reasoning domain into the description. These reasoning processes must reduce several levels of specific descriptions into only those few that most precisely describe the situation. Moreover, the system must be able to generate descriptions in the absence of data, as instructed by certain rules of inference. The deductions applied by the system, then, generate a high-level description from the low-level evidence provided by the real and default data sources. We describe an implementation of these ideas in a real-world situation. The application concerns evaluation of Space Shuttle electromechanical system configurations by console operators in the Mission Control Center. A production system provides the reasoning mechanism through which the default assignments and specializations occur. We provide examples within this domain for each type of inference, and discuss the suitability of each toward achieving our goal of describing a situation in the fewest statements possible. Finally, we suggest several enhancements that will further increase the intelligence of similar spacecraft monitoring applications.

Shuttle vector system for the analysis of mutational events in mammalian chromosomal DNA

cDNA of the human hprt gene was introduced into the BamHI cloning site of the retroviral shuttle vector pZipNeoSV(X)1. The mouse cell line 2TGOR, a hypoxanthine phosphoribosyltransferase-deficient derivative of Balb/c 3T3, was tranformed with the vector and some stably transformed HAT rNEO r clones were established. One of the clones, VH-12, contained a single copy of the vector integrated stably into a chromosome in a proviral form. From this clone, we were able to recover efficiently the vector sequence preserving its intact strucure by use of COS cell fusion. The relatively small size of the hprt cDNA (657 base pairs for the coding region) allowed quick determination of the entire DNA sequence. It was also notable that use of 6TG NEO double selection for mutant isolation could eliminate the 6TG r derivatives of VH-12 cells which arose from loss of the total vector sequence or from some epigenetic event, because such alterations would lead to inactivation of the neo gene as well as the hprt cDNA. The properties of our shuttle vector system were particularly useful for analysis of the molecular mechanisms of mutational events in chromosomal DNA of mammalian cells.

Launch processing system operations with a future look to operations analyst (OPERA)

The launch processing system at Kennedy Space Center is used to process a Shuttle vehicle from its initial arrival in an Orbiter processing facility to a launch pad. This paper describes the launch processing system architecture and the ground support operations required to provide Shuttle system engineers with the capability to safely process and launch an Orbiter. The described ground operations are the culmination of 11 years of experience and redesign. In this paper, I examine some of the “lessons learned” and discuss problem areas which ground support operations have identified over the years as the Shuttle and launch processing systems continue to grow in complexity. As we strive to maintain the efficient level of support currently provided, some benefits have been gained through standard information management and automation techniques. However, problems requiring complex correlational analyses of information have defied resolution until artificial intelligence research developed expert system applications technology. The operational analyst for distributed systems (OPERA), a proposed set of expert systems for launch processing system operational assistance, is discussed along with its extensions to prospective future configurations and components for the launch processing system.

Shuttle Entry Air Data System preflight testing and analysis

Data from the Shuttle Entry Air Data System (SEADS) port arcjet test were correlated using conventional finite difference thermal analysis methods to demonstrate the applicability of such methods to flight analyses. The arcjet tests were conducted to demonstrate the integrity of the SEADS-coated columbium port and provide data required to accomplish SEADS preflight analysis. The successful correlation of the results from finite difference thermal analysis methods and the test data demonstrated these methods for flight analysis. Using these techniques, a preflight analysis of the SEADS was performed and it was concluded that the maximum port temperature will be at a safe level for the first SEADS mission.

Analysis of mutation in human cells by using an Epstein-Barr virus shuttle system.

We developed highly sensitive shuttle vector systems for detection of mutations formed in human cells using autonomously replicating derivatives of Epstein-Barr virus (EBV). EBV vectors carrying the bacterial lacI gene as the target for mutation were established in human cells and later returned to Escherichia coli for rapid detection and analysis of lacI mutations. The majority of the clonal cell lines created by establishment of the lacI-EBV vector show spontaneous LacI- frequencies of less than 10(-5) and are suitable for studies of induced mutation. The ability to isolate clonal lines represents a major advantage of the EBV vectors over transiently replicating shuttle vectors (such as those derived from simian virus 40) for the study of mutation. The DNA sequence changes were determined for 61 lacI mutations induced by exposure of one of the cell lines to N-nitroso-N-methylurea. A total of 33 of 34 lacI nonsense mutations and 26 of 27 missense mutations involve G X C to A X T transitions. These data provide support for the mutational theory of cancer.

Recent Space Shuttle Crew Compartment Design Improvements

Significant design changes to the Space Shuttle waste management system (WMS) and its related personal hygiene support provisions (PHSP) have been made recently to improve overall operational performance and human factors interfaces. The WMS design improvements involve increased urinal flow, individual urinals, and provisions for manually compacting feces and cleanup materials to ensure adequate mission capacity. The basic arrangement and stowage of the PHSP used during waste management operations were extensively changed to better serve habitability concerns and operations needs, and to improve the hygiene of WMS operations. This paper describes these changes and the design, development, and flight test evaluation. In addition, provisions for an eighth crewmember and a new four-tier sleep station, are described.

Evolution and logistics of an early lunar base

The planned construction of a permanently manned space station in low earth orbit has reopened the discussion about the establishment of a manned lunar base within the next 25 years for exploration of the Moon and space. Several studies demonstrate that a lunar base very modest in size may cost $50 to 90 billion spread over 25 years which would fit into the expected NASA budget for this period. Having these cost in mind the authors present a concept having a greater effectiveness based on the following operational characteristics: (1) The development of a low cost heavy-lift launch vehicle for cargo transportation and propellant supply reduces the specific transportation cost by one order of magnitude compared to the existing Space Shuttle system. (2) Orbital transfer vehicles with LOX/LH2 technology should be preferred over advanced propulsion systems because of proved technology and cost reduction by utilization of lunar produced LOX. (3) The evolution of the lunar base towards a lunar colony and manufacturing facility could only be initiated by a powerful transportation system allowing for cost-effective space construction projects and manned spaceflight to other planets. The lunar base program of this paper is based on a schedule considering a 8 years development, 5 years lunar base assembly and 20 years operational phase during which the lunar crew will increase from 60 to 180 people. Launch rates will be 10 shuttle launches and 10 HLLV launches p.a. at the average. Development costs of the transportation and lunar base system will amount to $29 billion. Adding hardware and operational costs for lunar base assembly results in the acquisition cost of $49 billion. Total life cycle costs are estimated to be in the order of $101 billion considering a 20 years operational phase which will cost $2.6 billion p.a. at the average. For the 2508 man-years spent in lunosphere the relative cost will be $40.2 million per man-year of which space transportation will cost $25.0 million per man-year.

Space technology today

Technologies developed in support of our civil space program have progressed considerably over the 25‐year life of the National Aeronautics and Space Administration. Many of these advances are the result of a continuing increase in knowledge relative to the environment of space and the utilization of these previously designated hostile elements to gain design application advantages. Much more significant utilization of the environmental elements is forecast as space research and commercial goals and objectives begin to gain momentum. Challenges in the design of our Shuttle System and the next major goal, the Space Station, are significant and will result in greater utilization of the microgravity and vacuum of space as a benefit to research and operational goals.

Experimental aerodynamic heating to simulated Shuttle tiles

The heat transfer to simulated Shuttle thermal protection system tiles was investigated experimentally using a highly instrumented metallic thin wall tile arranged with other metal tiles in a staggered tile array. Cold-wall heating rate data for laminar and turbulent flow were obtained in the Langley 8-Foot High-Temperature Tunnel at a nominal Mach number of 7, a nominal total temperature of 3300 deg R, free-stream unit Reynolds number from 340,000 to 2,200,000 per foot, and free-stream dynamic pressure of 1.8 to 9.1 psia. Experimental data are presented to illustrate the effects of flow angularity and gap width on both local peak heating and overall heating loads.

Natural environment considerations for Space Shuttle system development support

Natural environments were determined for each of the Shuttle mission phases as a guide to design and operational decisions. The phases were categorized as mission planning, prelaunch, launch/ascent, booster recovery, on-orbit, and descent and landing. The wind criteria included magnitude/height, gust factors, turbulence spectra, wind shear, and vector properties for all flight and ground phases. A maximum design risk of 1 percent was permitted for the windiest two weeks the Shuttle would have to stay on the pad at either KSC or Vandenberg. The ascent wind profile was determined with the Jimsphere Vector Wind profiles, which cover the wind speeds, shears, gusts, and turbulence up to 18 km altitude. The models used to define the environmental situations of the Shuttle comprised wind, thermodynamic, space, lightning, sea state, mission analysis, and ET ice data base formulations.

The Space Shuttle system

The development and subsequent operation of the Shuttle as America’s primary space transportation system is the culmination of several decades of research, technology application and engineering. This vast endeavour, which has enjoyed unprecedented success to date, is one of the great team efforts in our technological history. From the pioneering efforts of Goddard and Tsiolkovsky, the critical contributions of von Karman, the insight of Faget, and the dedicated efforts of a multitude of others, the Shuttle has become a reality. The initial phases of Shuttle development involved extensive analysis and testing with margins carefully engineered to provide for technical contingencies, and operational results have verified the elegance of the design. Though its capability to carry cargo has received the most attention, the Shuttle’s capabilities in orbit will undoubtedly play a key role in the development of entirely new technologies and associated industries peculiar to the space environment. This paper will discuss the evolution of the Shuttle system and postulate its future contributions to the industrialization of space.

Control techniques to improve Space Shuttle solid rocket booster separation

The present Space Shuttle's control system does not prevent the Orbiter's main engines from being in gimbal positions that are adverse to solid rocket booster separation. By eliminating the attitude error and attitude rate feedback just prior to solid rocket booster separation, the detrimental effects of the Orbiter's main engines can be reduced. In addition, if angular acceleration feedback is applied, the gimbal torques produced by the Orbiter's engines can reduce the detrimental effects of the aerodynamic torques. This paper develops these control techniques and compares the separation capability of the developed control systems. Currently with the worst case initial conditions and each Shuttle system dispersion aligned in the worst direction (which is more conservative than will be experienced in flight), the solid rocket booster has an interference with the Shuttle's external tank of 30 in. Elimination of the attitude error and attitude rate feedback reduces that interference to 19 in. Substitution of angular acceleration feedback reduces the interference to 6 in. The two latter interferences can be eliminated by atess conservative analysis techniques, that is, by using a root sum square of the system dispersions.

Comparison of Shuttle Flight Pressure Data to Computational and Wind-Tunnel Results

A comparison between orbiter development flight instrumentation (DFI) forward fuselage flight pressure data, obtained from OV-102 during the space transportation system's (STS-1) re-entry, and ground facility and computational results is presented. Wind-tunnel data were obtained on a 0.04-scale orbiter forebody model. Computational data were obtained from the high alpha inviscid solutions (HALIS) computer code. These comparisons will be used to validate the existing experimental data base and optimize pressure modeling techniques developed in support of the Shuttle entry air data system (SEADS). The SEADS is a proposed acrossthe-speed-range second-generation air data system for the orbiter, using an array of flush pressure taps to be installed in the orbiter nose cap and forward fuselage. Knowledge derived from these comparisons will contribute to an improved capability to predict the performance of existing flight systems as well as an improved capability to design space transportation and general flight systems.

Economic considerations of the determination of investments for launch vehicle costs in the next two decades (1980–2000)

Investments in launch vehicle costs will be substantial in the next two decades, both in the RDT & E as well as the investment/operation phases. For Europe the “investment”; question is further complicated by the choice of (a) making full use of the Space Shuttle system or (b) further expansion and development of Shuttle independent space transportation capabilities. Considerations on future launch vehicle costs will be increasingly resolved on purely economic grounds: are the proposed investments economically efficient in the sense of the best use of these funds for space activities? Investments for reasosn of “prestige”; or “technology push” are probably better spent on payload programs, rather than space transportation systems. Economic considerations played a major factor in the choice of the space Shuttle system being developed in the United States. The economic considerations applied were: • • A comparison of space transportation systems (STS) costs of expendable vs reusable STSs of about $21 billion each (May 1979 dollars) • • The effects of different STSs on payload costs, including (1) RDT & E costs, (2) investment and operations costs and (3) on assured reliability of programs. (Repair, refurbishment, check-up capabilities) of about $63 billion (STS) and $76 billion (Expendables) respectively. These effects of STS on payload costs ($13 billion) often are lumped together under the term “payload effects”. They proved decisive in the choice of a Space Shuttle system, and the precise configuration now being developed and completed by NASA. Three economic evaluation approaches can be used separately or jointly when comparing space transportation system investments: • • Equal capability analyses • • Equal budget analyses • • New capability analyses. Looking ahead to investments into further launch vehicle developments in the 1980s and 1990s the same criteria will apply to any economic choice among rather expensive programs.

Quarter-Scale Space Shuttle Design, Fabrication, and Test

This paper discusses the design, fabrication, and dynamic testing of the quarter-scale model of the Space Shuttle system. As an integral part of the Shuttle design verification effort, the quarter-scale ground vibration test program was implemented to provide early verification of the dynamic characteristics of the Shuttle elements, both individually and in mated configurations. This paper presents the prominent aspects of the design and fabrication phases of the quarter-scale program and summarizes the ground vibration test program. Typical dynamic test data are presented and discussed. Future tests utilizing the quarter-scale vehicles are outlined.

Unique Nozzle Cover for the Shuttle Booster Separation Motors

Unique Nozzle Cover for the Shuttle Booster Separation Motors

The Global Positioning System and Its Application in Spacecraft Navigation

The paper presents an overview of the Global Positioning System (GPS) as well as a discussion of the user system parameters govering the design of a low-earth-orbit spacecraft GPS navigation system. A specific application, the Space Shuttle orbiter GPS navigation system, is discussed with particular attention given to its receiver/processor.

The Space Shuttle Its Interdisciplinary Design and Construction

AbstractMajor astronautical endeavors like the Space Shuttle Program apply the current state of progress in engineering, technology and art, as well as today s sophisticated administrative, economic and pOlitical systems. This review discusses the scope of scientific and engineering disciplines involved in the design and construction of the Space Shuttle – the world's first reusable space transportation system — now approaching flight readiness. Some background material is presented describing early concepts that led to the Shuttle design — the evolution of rocketry and manned orbital vehicles. Next, Shuttle operations and capabilities are explained. Shuttle system development is used to illustrate how the diverse technological disciplines were integrated — a function that has been maturing over the year into the process of systems engineering. Some of the Shuttle's complex subsystems and challenging requirements are discussed in detail to exemplify the coordination of elements associated with systems eng...

Performance Analysis of Pulse Doppler Digital Radars with Application to the Shuttle Ku-Band System

The performance of a class of pulse Doppler radars with a digitally implemented signal processing unit is investigated. The Ku band rendezvous radar onboard the Shuttle Orbiter is a pulse Doppler radar which is in this class. The detection capability is first presented. A unified analysis of digital radar tracking loops is presented which employs logarithmic discriminants. The results are applied to angle, range, and range rate tracking loops. Numerical results of the amplitude monopulse angle tracking loop are presented for the Ku -band rendezvous radar of the Space Shuttle.

Space Shuttle Payloads and Data Handling Accommodations

This paper provides an overview of the various classes of candidate payloads to be flown on early Shuttle missions and summarizes the communications and data handling services which the Space Shuttle will provide for payloads. The Space Shuttle system mission capabilities are briefly described and data processing capabilities for payload support are discussed for the various classes of payloads.