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A management systems study for future spacesuit programs was conducted to assess past suit program requirements and management systems in addition to new and modified systems in order to identify the most cost effective methods for use during future spacesuit programs. The effort and its findings concerned the development and production of all hardware ranging from crew protective gear to total launch vehicles.
The paper summarizes a system study of the solar power satellite (SPS) concept which was conducted in the 1977-1980 time period. The system study was sponsored by the U.S. Department of Energy and the National Aeronautics and Space Administration as part of an SPS Concept Development and Evaluation Program. A reference system, developed during the study is described. The reference system was subsequently used as a basis for environmental, economic, and societal assessments. The reference system was recognized as probably not being an optimized approach. A number of alternate approaches which were studied in less depth are also described. The paper concludes with a number of observations regarding the SPS concept, and the pertinence of ongoing space technology, development, and flight programs to various aspects of the concept.
The report describes the work breakdown structure (WBS) and its associated WBS dictionary for task area 1 of contract NAS8-39207, advanced transportation system studies (ATSS). This WBS format is consistent with the preliminary design level of detail employed by both task area 1 and task area 4 in the ATSS study and is intended to provide an estimating structure for parametric cost estimates.
The Manned Transpiration System (MTS) Study was undertaken to develop key data relative to the United States manned transportation system, and specifically, the next manned system we build. These data are being developed in the context of Earth-to-orbit architectures necessary to deliver all government payloads to low Earth orbit (LEO). Launch systems, transition between current and new systems, along with system functions (personnel and/or cargo to/from orbit) are presented. Several key considerations being debated today were used to aid our selection of Earth-to-orbit (ETO) architectures for evaluation. Other consideration s not being addressed in this initial effort that require additional study are identified Twenty-five launch systems were used to define a set of 18 architectures. These architectures are discussed in context with they key considerations being addressed in this study. Payload manufacturing ground rules are presented to provide an understanding of our approach in establishing flight rates from the MTS mission models. Furthermore, a discussion of manned system flight rates and relative personnel safety characteristics differences is presented. Comparative architecture results will not be available until May 1992.
The results of several NASA sponsored high density short haul air transportation systems studies are reported as well as analyzed. Included are the total STOL systems analysis approach, a companion STOL composites study conducted in conjunction with STOL systems studies, a STOL economic assessment study, an evaluation of STOL aircraft with and without externally blown flaps, an alternative STOL systems for the San Francisco Bay Area, and the quiet, clean experimental engine studies. Assumptions and results of these studies are summarized, their differences, analyzed, and the results compared with those in-house analyses performed by the Systems Studies Division of the NASA-Ames Research Center. Pertinent conclusions are developed and the more significant technology needs for the evaluation of a viable short haul transportation system are identified.
Late in 1990, the NASA Systems Integration Group began functioning and the aircraft systems studies entered a second phase. This group proposed tightly coordinated Ames/Langley/Lewis/industry studies that would address a series of tasks to evaluate progress, recommend appropriate direction, and emphasize changes in technology elements based on system level payoffs and potential success assessments. Based on technical and economic assessment studies of the High Speed Civil Transport (HSCT) to date, Mach 2.4 was chosen as the primary focus for the High Speed Research Program with Mach numbers 2.0 and 1.6 being backups in case of technology shortfalls. Langley has established an interdisciplinary team to strengthen the multidisciplinary aspects of aircraft design and analysis. The vehicle focus of this team is the HSCT. At Langley, early HSCT studies focused on turbojet powered aircraft. They also concluded that variable sweep wing concepts require 50/50 subsonic/supersonic to payoff for Mach 3.0 concept. Progress has been good in low sonic boom concepts.
The Long Term Cryogenic Storage Facility Systems Study (LTCSFSS) is a Phase A study of a large capacity propellant depot for the space based, cryogenic orbital transfer vehicle. The study is being performed for Marshall Space Flight Center by General Dynamics Space Systems Division and has five principal objectives: (1) Definition of preliminary concept designs for four storage facility concepts; (2) Selection of preferred concepts through the application of trade studies to candidate propellant management system components; (3) Preparation of a conceptual design for an orbital storage facility; (4) Development of supporting research and technology requirements; and (5) Development of a test program to demonstrate facility performance. The initial study has been completed, and continuation activities are just getting under way to provide greater detail in key areas and accommodate changes in study guidelines and assumptions.
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Several thrust system design concepts were evaluated and compared using the specifications of the most advanced 30- cm engineering model thruster as the technology base. Emphasis was placed on relatively high-power missions (60 to 100 kW) such as a Halley's comet rendezvous. The extensions in thruster performance required for the Halley's comet mission were defined and alternative thrust system concepts were designed in sufficient detail for comparing mass, efficiency, reliability, structure, and thermal characteristics. Confirmation testing and analysis of thruster and power-processing components were performed, and the feasibility of satisfying extended performance requirements was verified. A baseline design was selected from the alternatives considered, and the design analysis and documentation were refined. The baseline thrust system design features modular construction, conventional power processing, and a concentractor solar array concept and is designed to interface with the space shuttle.
The current phase of the Space Station Operating System study is based on the analysis, evaluation, and comparison of the operating systems implemented on the computer systems and workstations in the software development laboratory. Primary emphasis has been placed on the DEC MicroVMS operating system as implemented on the MicroVax II computer, with comparative analysis of the SUN UNIX system on the SUN 3/260 workstation computer, and to a limited extent, the IBM PC/AT microcomputer running PC-DOS. Some benchmark development and testing was also done for the Motorola MC68010 (VM03 system) before the system was taken from the laboratory. These systems were studied with the objective of determining their capability to support Space Station software development requirements, specifically for multi-tasking and real-time applications. The methodology utilized consisted of development, execution, and analysis of benchmark programs and test software, and the experimentation and analysis of specific features of the system or compilers in the study.
A control system concept is presented that produces proportional control of yaw moment for the space shuttle from early entry to Mach 2 with only software modifications of the vehicle. It uses separate deflections of the inboard and outboard elevon surfaces and is evaluated, by determining the maximum static yawing moment available by considering the deflection limits of the elevon surfaces. A proportional moment slightly in excess of that produced by the most effective reaction control system (RCS) jet for yaw control can be obtained. In addition to the static moment study, a control law is designed which is intended to produce desired flying qualities.
The main objective was to determine viable methods for starting the Space Shuttle Main Engine (SSME) in an altitude environment and restarting it in an orbit environment with minimum changes in utilization of the engine system or hardware. The study concluded that the use of the SSME in an upper stage is feasible with minimal changes to the engine systems. The altitude start case requires only a change in the valve sequencing during start and reorificing of the ASI lines. Inlet pressures can be moderately low at 40 psia for the LOX and 32 psia for the H2. The orbital restart case adds the need to recirculate propellant and thermal control paint (to keep the turbomachinery inlets cold to minimize the tank pressures needed), and the need to heat two small components (to maintain acceptable mixture ratios during the early part of the start). These actions allow start anytime after approximately 120 minutes. Earlier starts (approximately one hour) are also possible but would require additional component heating for mixture ratio control during the early portion of the start sequence.
A detailed; mission-level systems study has been performed to show the benefit resulting from engine performance gains that will result from NASA's In-Space Propulsion ROSS Cycle 3A NRA, Advanced Chemical Technology sub-topic. The technology development roadmap to accomplish the NRA goals are also detailed in this paper. NASA-Marshall and NASA-JPL have conducted mission-level studies to define engine requirements, operating conditions, and interfaces. Five reference missions have been chosen for this analysis based on scientific interest, current launch vehicle capability and trends in space craft size: a) GTO to GEO, 4800 kg, delta-V for GEO insertion only approx.1830 m/s; b) Titan Orbiter with aerocapture, 6620 kg, total delta V approx.210 m/s, mostly for periapsis raise after aerocapture; c) Enceladus Orbiter (Titan aerocapture) 6620 kg, delta V approx.2400 m/s; d) Europa Orbiter, 2170 kg, total delta V approx.2600 m/s; and e) Mars Orbiter, 2250 kg, total delta V approx.1860 m/s. The figures of merit used to define the benefit of increased propulsion efficiency at the spacecraft level include propulsion subsystem wet mass, volume and overall cost. The objective of the NRA is to increase the specific impulse of pressure-fed earth storable bipropellant rocket engines to greater than 330 seconds with nitrogen tetroxide and monomothylhydrazine propellants and greater than 335 , seconds with nitrogen tetroxide and hydrazine. Achievement of the NRA goals will significantly benefit NASA interplanetary missions and other government and commercial opportunities by enabling reduced launch weight and/or increased payload. The study also constitutes a crucial stepping stone to future development, such as pump-fed storable engines.
Systems analysis for ERTS ground data handling system and operations control center
Systems analysis for ERTS NASA Data Processing Facility system and subsystems
Systems analysis for ERTS NASA Data Processing Facility subsystems, installation, and support functions
An optical system which can be incorporated in a present day or near future space-borne laser communications system is described. Techniques of implementing these systems are presented and their design problems and use are discussed. Optical system weight is estimated as a function of aperture diameter for a typical present day or near future laser communication system. The optical communications system considered is a two-way, high data rate optical communications link from a spacecraft to a spacecraft or from a spacecraft to a ground station. Each station has a laser transmitter and receiver and a pointing and tracking system. Thus each station can track the laser transmitter of the other. Optical beamwidths are considered to be as small as an arc-second with the beam pointed to a fraction of this beamwidth.
The High Speed Civil Transport (HSCT) mission perspective is given, along with the systems studies goals, a configuration for the commercially viable HSCT, and a summary of the HSCT airframe systems studies during phases 1, 2, and 3. The environment effect goals are also presented, along with the airplane size projections, low sonic boom technology, and conclusions.