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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 559 records · Page 31
All sourcesNASA NTRSDOE OSTI
NASA NTRS1989

Conceptual design of a communications system for Mars exploration missions

Future missions to Mars will require a communications system to link activities on the Martian surface with each other and with mission controllers on earth. This paper documents the preliminary design of an areosynchronous communications satellite to provide such links. As designed, the satellite will provide almost continuous communication between Mars and earth, as well as continuous Mars surface-to-surface links. The capacity will exist for voice, data/command, and video transmission. The mission scenario assumed for this design is described, followed by the configuration design. The communications systems conceptual design and its impact on the overall spacecraft requirements are then presented. Supporting subsystems including electrical power; thermal control; guidance, navigation, and control; propulsion; structures; and configuration are reviewed. A description of the operating orbit and the assumed method of orbit acquisition are discussed.

Badi, Deborah M.↗
NASA NTRS1989

Unmanned and manned Mars missions - Aeroassist technology needs and issues

The critical aeroassist technologies are considered, with consideration given to the manned and unmanned Mars missions. Attention is given to the aerothermal characterization, the thermal-protection system (TPS), the guidance navigation and control systems, and atmospheric uncertainties. Particular consideration is given to the aerobrake assembly concepts for an unmanned Mars mission, and to programmatics.

Willcockson, W. H.↗
NASA NTRS1990

ACES: Space shuttle flight software analysis expert system

The Analysis Criteria Evaluation System (ACES) is a knowledge based expert system that automates the final certification of the Space Shuttle onboard flight software. Guidance, navigation and control of the Space Shuttle through all its flight phases are accomplished by a complex onboard flight software system. This software is reconfigured for each flight to allow thousands of mission-specific parameters to be introduced and must therefore be thoroughly certified prior to each flight. This certification is performed in ground simulations by executing the software in the flight computers. Flight trajectories from liftoff to landing, including abort scenarios, are simulated and the results are stored for analysis. The current methodology of performing this analysis is repetitive and requires many man-hours. The ultimate goals of ACES are to capture the knowledge of the current experts and improve the quality and reduce the manpower required to certify the Space Shuttle onboard flight software.

Satterwhite, R. Scott↗
NASA NTRS1989

Demonstrating system for servicing satellites

NASA has initiated a program to demonstrate a Satellite Servicer System prototype in a series of flight tests with the Space Shuttle. When the commitment to an operational system has been demonstrated, it is anticipated that a variety of missions will develop that can productively use the servicing capability. Rendezvous and proximity operations contain key enabling technologies needed for an effective operational system. Guidance, navigation and control hardware and operational techniques must be integrated into the program. Supporting sensor technology may limit or enhance the capability of the system depending on its readiness. Requirements for docking the spacecraft in the system concept development and technology requirements are reviewed. Examples of the initial assessment of technology readiness and applications opportunities are discussed. The degree of autonomy is of particular interest.

Jenkins, Lyle M.↗
NASA NTRS1989

Evolutionary growth for Space Station Freedom electrical power system

Over an operational lifetime of at least 30 yr, Space Station Freedom will encounter increased Space Station user requirements and advancing technologies. The Space Station electrical power system is designed with the flexibility to accommodate these emerging technologies and expert systems and is being designed with the necessary software hooks and hardware scars to accommodate increased growth demand. The electrical power system is planned to grow from the initial 75 kW up to 300 kW. The Phase 1 station will utilize photovoltaic arrays to produce the electrical power; however, for growth to 300 kW, solar dynamic power modules will be utilized. Pairs of 25 kW solar dynamic power modules will be added to the station to reach the power growth level. The addition of solar dynamic power in the growth phase places constraints in the initial Space Station systems such as guidance, navigation, and control, external thermal, truss structural stiffness, computational capabilities and storage, which must be planned-in, in order to facilitate the addition of the solar dynamic modules.

Marshall, Matthew Fisk↗
NASA NTRS1990

Final shuttle-derived atmospheric database: Development and results from thirty-two flights

The final Shuttle-derived atmospheric data base is presented. The relational data base is comprised of data from 32 Space Transportation System (STS) descent flights, to include available meteorology data taken in support of each flight. For the most part, the available data are restricted to the middle atmosphere. In situ accelerations, sensed by the tri-redundant Inertial Measurement Unit (IMU) to an accuracy better than 1 mg, are combined with post-flight Best Estimate Trajectory (BET) information and predicted, flight-substantiated Orbiter aerodynamics to provide determinations up to altitudes of 95 km. In some instances, alternate accelerometry data with micro-g resolution were utilized to extend the data base well into the thermosphere. Though somewhat limited, the ensemble of flights permit a reasonable sampling of monthly, seasonal, and latitudinal variations which can be utilized for atmospheric science investigations and model evaluations and upgrades as appropriate. More significantly, the unparallel vertical resolution in the Shuttle-derived results indicate density shears normally associated with internal gravity waves or local atmospheric instabilities. Consequently, these atmospheres can also be used as stress-atmospheres for Guidance, Navigation and Control (GN and C) system development and analysis as part of any advanced space vehicle design activities.

Findlay, John T.↗
NASA NTRS1990

Space transfer concepts and analysis for exploration missions

The progress and results are summarized for mission/system requirements database; mission analysis; GN and C (Guidance, Navigation, and Control), aeroheating, Mars landing; radiation protection; aerobrake mass analysis; Shuttle-Z, TMIS (Trans-Mars Injection Stage); Long Duration Habitat Trade Study; evolutionary lunar and Mars options; NTR (Nuclear Thermal Rocket); NEP (Nuclear Electric Propulsion) update; SEP (Solar Electric Propulsion) update; orbital and space-based requirements; technology; piloted rover; programmatic task; and evolutionary and innovative architecture.

Source record↗
NASA NTRS1990

Flight elements subpanel

A summary of findings of the Flight Elements Subpanel is given in viewgraph form. Topics covered include advanced avionics architecture; processors; integrated Global Positioning System and guidance, navigation and control; displays and controls; telemetry; sensors and instrumentation; fault detection and management; electrical power distribution and control; spacecraft power supplies; and in-flight crew training.

Keckler, Claude R.↗
NASA NTRS1990

Joint University Program for Air Transportation Research, 1989-1990

Research conducted during the academic year 1989-90 under the NASA/FAA sponsored Joint University Program for Air Transportation research is discussed. Completed works, status reports and annotated bibliographies are presented for research topics, which include navigation, guidance and control theory and practice, aircraft performance, human factors, and expert systems concepts applied to airport operations. An overview of the year's activities for each university is also presented.

Morrell, Frederick R.↗
NASA NTRS1991

Technologies for aerobraking

Aerobraking is one of the largest contributors to making both lunar and Mars missions affordable. The use of aerobraking/aeroassist over all propulsive approaches saves as much as 60 percent of the initial mass required in low earth orbit (LEO); thus, the number and size of earth to orbit launch vehicles is reduced. Lunar transfer vehicles (LTV), which will be used to transport personnel and materials from LEO to lunar outpost, will aerobrake into earth's atmosphere at approximately 11 km/sec on return from the lunar surface. Current plans for both manned and robotic missions to Mars use aerocapture during arrival at Mars and at return to Earth. At Mars, the entry velocities will range from about 6 to 9.5 km/sec, and at Earth the return velocity will be about 12.5 to 14 km/sec. These entry velocities depend on trajectories, flight dates, and mission scenarios and bound the range of velocities required for the current studies. In order to successfully design aerobrakes to withstand the aerodynamic forces and heating associated with these entry velocities, as well as to make them efficient, several critical technologies must be developed. These are vehicle concepts and configurations, aerothermodynamics, thermal protection system materials, and guidance, navigation, and control systems. The status of each of these technologies are described, and what must be accomplished in each area to meet the requirements of the Space Exploration Initiative is outlined.

Cooper, David M.↗
NASA NTRS1990

Technologies for aerobraking

Aerobraking is one of the largest contributors to making both lunar and Mars missions affordable. The use of aerobraking/aeroassist over all-propulsive approaches saves as much as 60 percent of the initial mass required in LEO, thus reducing the number and size of earth-to-orbit launch vehicles. Lunar transfer vehicles, which will be used to transport personnel and materials from LEO to lunar outposts, will aerobrake into earth's atmosphere at aproximately 11 km/sec on return from the lunar surface. Current plans for both manned and robotic missions to Mars use aerocapture during arrival at Mars and at earth return. At Mars, the entry velocities will range from about 6 to 9.5 km/sec, and at earth the return velocity will be about 12.5 to 14 km/sec. In order to successfully design aerobrakes to withstand the aerodynamic forces and heating associated with these entry velocities, as well as to make them efficient, several critical technologies must be developed. These are vehicle concepts and configurations, aerothermodynamics, thermal protection system materials, and guidance, navigation, and control systems. This paper describes the status of each of these technologies and outlines what must be accomplished in each area to meet the requirements of the Space Exploration Initiative.

Cooper, David M.↗
NASA NTRS1990

Statistical analysis of AFE GN&C aeropass performance

Performance of the guidance, navigation, and control (GN&C) system used on the Aeroassist Flight Experiment (AFE) spacecraft has been studied with Monte Carlo techniques. The performance of the AFE GN&C is investigated with a 6-DOF numerical dynamic model which includes a Global Reference Atmospheric Model (GRAM) and a gravitational model with oblateness corrections. The study considers all the uncertainties due to the environment and the system itself. In the AFE's aeropass phase, perturbations on the system performance are caused by an error space which has over 20 dimensions of the correlated/uncorrelated error sources. The goal of this study is to determine, in a statistical sense, how much flight path angle error can be tolerated at entry interface (EI) and still have acceptable delta-V capability at exit to position the AFE spacecraft for recovery. Assuming there is fuel available to produce 380 ft/sec of delta-V at atmospheric exit, a 3-sigma standard deviation in flight path angle error of 0.04 degrees at EI would result in a 98-percent probability of mission success.

Chang, Ho-Pen↗
NASA NTRS1991

Cryogenic propellant management system requirements for Space Station Freedom

Specific propellant management system requirements have been identified for each facility category of SSF. Distributed systems have been analyzed to indentify momentum management, guidance, and traffic management requirements associated with the guidance, navigation, and control system; space-to-space communications and enhanced tracking requirements associated with the communications and tracking system; and propellant management system utility requirements associated with the electrical power system. Flight element analyses determined attach structure, utility distribution, and structural integrity requirements for the pre-integrated truss and high mass manipulation and translation requirements for the mobile base system.

Saucillo, R. J.↗
NASA NTRS1991

Avionics Subsystem

The avionics subsystem of the Common Lunar Lander (CLL) is designed to meet the following requirements: guidance, navigation, and control of the spacecraft; central computer for all subsystems; and data storage for all subsystems for telemetry purposes. A table describing the av ionics subsystem is listed. Additionally, a schematic representation of the avionics subsystem is provided.

Smith, Nancy C.↗
NASA NTRS1992

NASA TSRV essential flight control system requirements via object oriented analysis

The objective was to analyze the baseline flight control system of the Transport Systems Research Vehicle (TSRV) and to develop a system specification that offers high visibility of the essential system requirements in order to facilitate the future development of alternate, more advanced software architectures. The flight control system is defined to be the baseline software for the TSRV research flight deck, including all navigation, guidance, and control functions, and primary pilot displays. The Object Oriented Analysis (OOA) methodology developed is used to develop a system requirement definition. The scope of the requirements definition contained herein is limited to a portion of the Flight Management/Flight Control computer functionality. The development of a partial system requirements definition is documented, and includes a discussion of the tasks required to increase the scope of the requirements definition and recommendations for follow-on research.

Duffy, Keith S.↗
NASA NTRS1992

Advanced Transport Operating System (ATOPS) control display unit software description

The software created for the Control Display Units (CDUs), used for the Advanced Transport Operating Systems (ATOPS) project, on the Transport Systems Research Vehicle (TSRV) is described. Module descriptions are presented in a standardized format which contains module purpose, calling sequence, a detailed description, and global references. The global reference section includes subroutines, functions, and common variables referenced by a particular module. The CDUs, one for the pilot and one for the copilot, are used for flight management purposes. Operations performed with the CDU affects the aircraft's guidance, navigation, and display software.

Slominski, Christopher J.↗
NASA NTRS1992

Automation and Robotics for Space-Based Systems, 1991

A NASA Langley workshop on Automation and Robotics for Space-Based Systems was held on December 10, 1991. This conference proceedings document presents the overhead slides from each speaker at this event. The purpose of this in-house workshop was to assess the state-of-the-art of automation and robotics for space operations from a LaRC perspective and to identify areas of opportunity for future research. The workshop was sponsored by the Guidance, Navigation, and Control Technical Committee, chaired by Mr. Raymond C. Montgomery. Nineteen talks were given, reflecting a high level of interest in the field of automation at NASA Langley. Over half of the presentations came from the Automation Technology Branch, covering telerobotic control, EVA and IVA robotics, hand controllers for teleoperation, sensors, neural networks, and automated structural assembly, all applied to space missions. Other talks covered RMS active damping augmentation, space crane work, modeling, simulation, and control of large, flexible space manipulators, and virtual passive controller designs for space robots.

Automation↗
NASA NTRS1992

Common lunar lander

This report focuses on the reference lander design developed at the Johnson Space Center, describing a small lunar soft lander with the capability to soft land about 64 kilograms of payload at any lunar latitude and longitude. The Artemis lander is a sun-pointing, three-axis vehicle that contributes to the translunar injection burn and performs the lunar orbit insertion, deorbit, descent and landing maneuvers with a single liquid bipropellant lander stage. Attention is given to mission profile and performance, the guidance, navigation and control subsystem, the propulsion subsystem, and the flight data subsystem.

Bailey, S.↗