Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “GUIDANCE AND CONTROL”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 559 records · Page 31
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Apollo guidance, navigation, and control: Candidate configuration trade study, Stellar-Inertial Measurement System (SIMS) for an Earth Observation Satellite (EOS)

The ten candidate SIMS configurations were reduced to three in preparation for the final trade comparison. The report emphasizes subsystem design trades, star availability studies, data processing (smoothing) methods, and the analytical and simulation studies at subsystem and system levels from which candidate accuracy estimates will be presented.

Ogletree, G.↗
NASA NTRS1972

Space shuttle orbiter guidance, naviagation and control software functional requirements: Horizontal flight operations

The shuttle GN&C software functions for horizontal flight operations are defined. Software functional requirements are grouped into two categories: first horizontal flight requirements and full mission horizontal flight requirements. The document privides the intial step in the shuttle GN&C software design process. It also serves as a management tool to identify analyses which are required to define requirements.

Source record↗
NASA NTRS1972

Space shuttle guidance, navigation and control equation document no. 4: Precision state and filter weighting matrix extrapolation

The Precision State and Filter Weighting Matrix Extrapolation Routine is described which provides the capability to extrapolate any spacecraft geocentric state vector either backwards or forwards in time through a force field consisting of the earth's primary central-force gravitational attraction and a superimposed perturbing acceleration. The routine also provides the capability of extrapolating the filter-weighting matrix along the precision trajectory. This matrix is a square root form of the error covariance matrix and contains statistical information relative to the accuracies of the state vectors and certain other optionally estimated quantities. The routine is a cooled algorithm for the numerical solution of modified forms of the basic differential equations which are satisfied by the geocentric state vector of the spacecraft's center of mass and by the filter-weighting matrix.

Robertson, W. M.↗
NASA NTRS1972

Space shuttle guidance, navigation and control equation document no. 19: Prelaunch alignment and platform compensation

The prelaunch-alignment program which aligns the stable platform to some desired orientation with respect to the local navigation reference frame is discussed. The alignment progresses in three distinct phases: coarse aligning, leveling, and gyrocompassing. While the program is in the leveling or gyrocompassing phase, a new launch azimuth may be specified without reinitiating the program. At liftoff, control is passed to a navigation monitor/control program. A description of the stable-platform-compensation program is included. The programs and equations given are similar to those used for Apollo.

Gallagher, J. L.↗
NASA NTRS1972

Apollo 15 mission report: Apollo 15 guidance, navigation, and control system performance analysis report (supplement 1)

This report contains the results of additional studies which were conducted to confirm the conclusions of the MSC Mission Report and contains analyses which were not completed in time to meet the mission report deadline. The LM IMU data were examined during the lunar descent and ascent phases. Most of the PGNCS descent absolute velocity error was caused by platform misalignments. PGNCS radial velocity divergence from AGS during the early part of descent was partially caused by PGNCS gravity computation differences from AGS. The remainder of the differences between PGNCS and AGS velocity were easily attributable to attitude reference alignment differences and tolerable instrument errors. For ascent the PGNCS radial velocity error at insertion was examined. The total error of 10.8 ft/sec was well within mission constraints but larger than expected. Of the total error, 2.30 ft/sec was PIPA bias error, which was suspected to exist pre-lunar liftoff. The remaining 8.5 ft/sec is most probably satisified with a large pre-liftoff planform misalignment.

Source record↗
NASA NTRS1983

IPACS Guidance Navigation and Control System Considerations and Test Activities

The MSFC facility proposed for the Space Station Attitude Control Simulator which consists of a large three degree of freedom table driven by computer controlled hydraulic actuators designed to give high bandwidth and extremely fine control through large angles is outlined. The facility includes star and solar simulators providing collimated light with the spectral content and intensity typical of Earth orbit.

Buchanan, H. J.↗
NASA NTRS1991

Utilization of simulation tools in the HL-20 conceptual design process

The role of simulations in the design of the HL-20, the crew-carrying unpowered lifting-body component of the NASA Personnel Launch System, is reviewed and illustrated with drawings and diagrams. Detailed consideration is given to the overall implementation of a real-time simulation of the HL-20 approach and landing phase, the baseline and experimental control laws used in the flight-control system, autoland guidance and control laws (vertical and lateral steering), the control-surface mixer and actuator model, and simulation results. The simulations allowed identification and correction of design problems with respect to the position of the landing gear and the original maximum L/D ratio of 3.2.

Jackson, E. B.↗
NASA NTRS1993

Guidance and flight control law development for hypersonic vehicles

During the third reporting period our efforts were focused on a reformulation of the optimal control problem involving active state-variable inequality constraints. In the reformulated problem the optimization is carried out not with respect to all controllers, but only with respect to asymptotic controllers leading to the state constraint boundary. Intimately connected with the traditional formulation is the fact that when the reduced solution for such problems lies on a state constraint boundary, the corresponding boundary layer transitions are of finite time in the stretched time scale. Thus, it has been impossible so far to apply the classical asymptotic boundary layer theory to such problems. Moreover, the traditional formulation leads to optimal controllers that are one-sided, that is, they break down when a disturbance throws the system on the prohibited side of the state constraint boundary.

Calise, A. J.↗
NASA NTRS1995

Guidance, navigation, and control study for a solar electric propulsion spacecraft

A preliminary investigation of a lunar-comet rendezvous mission using a solar electric propulsion (SEP) spacecraft was performed in two phases.The first phase involved exploration of the moon and the second involved rendezvous with a comet. The initial phase began with a chemical propulsion translunar injection and chemical insertion into a lunar orbit, followed by a low thrust SEP transfer to a circular, polar, low-lunar orbit. After collecting scientific data at the moon, the SEP spacecraft performed a spiral lunar escape maneuver to begin the interplanetary leg of the mission. After escape from the Earth-moon system, the SEP spacecraft maneuvered in interplanetary space and performed a rendezvous with a comet.The immediate goal of this study was to demonstrate the feasibility of using a low-thrust SEP spacecraft for orbit transfer to both the moon and a comet. Another primary goal was to develop a computer optimization code which would be robust enough to obtain minimum-fuel rendezvous trajectories for a wide range of comets.

Kluever, Craig A.↗
NASA NTRS1999

Management of Guidance, Navigation, and Control Technologies for Spacecraft Formations Under the NASA Cross Enterprise Technology Development Program (CETDP)

Breakthrough technology development is critical to securing the future of our space industry. The National Aeronautics and Space Administration (NASA) Cross-Enterprise Technology Development Program (CETDP) is developing critical space technologies that enable innovative and less costly missions, and spawn new mission opportunities through revolutionary, long-term, high-risk, high-payoff technology advances. The CETDP is a NASA-wide activity managed by the Advanced Technology and Mission Studies Division (AT&MS) at Headquarters Office of Space Science. Program management for CETDP is distributed across the multiple NASA Centers and draws on expertise throughout the Agency. The technology research activities are organized along Project-level divisions called thrust areas that are directly linked to the Agency's goals and objectives of the Enterprises: Earth Science, Space Science, Human Exploration and Development of Space; and the Office of the Chief Technologist's (OCT) strategic technology areas. Cross-Enterprise technology is defined as long-range strategic technologies that have broad potential to span the needs of more than one Enterprise. Technology needs are identified and prioritized by each of the primary customers. The thrust area manager (TAM) for each division is responsible for the ultimate success of technologies within their area, and can draw from industry, academia, other government agencies, other CETDP thrust areas, and other NASA Centers to accomplish the goals of the thrust area. An overview of the CETDP and description of the future directions of the thrust area called Distributed Spacecraft are presented in this paper. Revolutionary technologies developed within this thrust area will enable the implementation of a spatially distributed network of individual vehicles, or assets, collaborating as a single collective unit, and exhibiting a common system-wide capability to accomplish a shared objective. With such a capability, new Earth and space science measurement concepts become a reality.

Hartman, Kathy↗
NASA NTRS1999

Management of Guidance, Navigation and Control Technologies for Spacecraft Formations under the NASA Cross-Enterprise Technology Development Program (CETDP)

Breakthrough technology development is critical to securing the future of our space industry. The National Aeronautics and Space Administration (NASA) Cross-Enterprise Technology Development Program (CETDP) is developing critical space technologies that enable innovative and less costly missions, and spawn new mission opportunities through revolutionary, long-term, high-risk, high-payoff technology advances. The CETDP is a NASA-wide activity managed by the Advanced Technology and Mission Studies Division (AT&MS) at Headquarters Office of Space Science. Program management for CETDP is distributed across the multiple NASA Centers and draws on expertise throughout the Agency. The technology research activities are organized along Project-level divisions called thrust areas that are directly linked to the Agency's goals and objectives of the Enterprises: Earth Science, Space Science, Human Exploration and Development of Space; and the Office of the Chief Technologist's (OCT) strategic technology areas. Cross-Enterprise technology is defined as long-range strategic technologies that have broad potential to span the needs of more than one Enterprise. Technology needs are identified and prioritized by each of the primary customers. The thrust area manager (TAM) for each division is responsible for the ultimate success of technologies within their area, and can draw from industry, academia, other government agencies, other CETDP thrust areas, and other NASA Centers to accomplish the goals of the thrust area. An overview of the CETDP and description of the future directions of the thrust area called Distributed Spacecraft are presented in this paper. Revolutionary technologies developed within this thrust area will enable the implementation of a spatially distributed network of individual vehicles, or assets, collaborating as a single collective unit, and exhibiting a common system-wide capability to accomplish a shared objective. With such a capability, new Earth and space science measurement concepts become a reality.

Hartman, Kathy↗
NASA NTRS2002

The Microwave Anisotropy Probe (MAP): Guidance, Navigation, and Control Hardware Suite

The Microwave Anisotropy Probe (MAP) was launched June 30, 2001 to create an all-sky map of the Cosmic Microwave Background. The mission's hardware suite included two Lockheed Martin AST-201 star trackers, two Kearfott Two-Axis Rate Assemblies (TARAs) mounted to provide X, Y and redundant Z-axis rates, two Adcole Digital Sun Sensor (DSS) heads sharing one set of electronics, twelve Adcole Coarse Sun Sensor (CSS) eyes, three Ithaco E-sized Reaction Wheel Assemblies (RWAs), and a Propulsion Subsystem that employed eight PRIMEX Rocket Engine Modules (REMs). This hardware has allowed MAP to meet its various Orbit and Attitude Control Requirements, including performing a complex zero-momentum scan, meeting its attitude determination requirements, and maintaining a trajectory that places MAP in a lissajous orbit around the second Sun-Earth Lagrange point (L2) via phasing loops and a lunar gravity assist. Details of MAP's attitude determination, attitude control, and trajectory design are presented separately. This paper will focus on the performance of the hardware components mentioned above, as well as the significant lessons learned through the use of these components. An emphasis will be placed on spacecraft design modifications that were needed to accommodate existing hardware designs into the MAP Observatory design.

Ward, David K.↗
NASA NTRS1998

Flight Testing of an Airport Surface Guidance, Navigation, and Control System

This document describes operations associated with a set of flight experiments and demonstrations using a Boeing-757-200 (B-757) research aircraft as part of low visibility landing and surface operations (LVLASO) research activities. To support this experiment, the B-757 performed flight and taxi operations at the Hartsfield-Atlanta International Airport (ATL) in Atlanta, GA. The B-757 was equipped with experimental displays that were designed to provide flight crews with sufficient information to enable safe, expedient surface operations in any weather condition down to a runway visual range (RVR) of 300 feet. In addition to flight deck displays and supporting equipment onboard the B-757, there was also a ground-based component of the system that provided for ground controller inputs and surveillance of airport surface movements. The integrated ground and airborne components resulted in a system that has the potential to significantly improve the safety and efficiency of airport surface movements particularly as weather conditions deteriorate. Several advanced technologies were employed to show the validity of the operational concept at a major airport facility, to validate flight simulation findings, and to assess each of the individual technologies performance in an airport environment. Results show that while the maturity of some of the technologies does not permit immediate implementation, the operational concept is valid and the performance is more than adequate in many areas.

Young, Steven D.↗
NASA NTRS1992

Stereo optical guidance system for control of industrial robots

A device for the generation of basic electrical signals which are supplied to a computerized processing complex for the operation of industrial robots. The system includes a stereo mirror arrangement for the projection of views from opposite sides of a visible indicia formed on a workpiece. The views are projected onto independent halves of the retina of a single camera. The camera retina is of the CCD (charge-coupled-device) type and is therefore capable of providing signals in response to the image projected thereupon. These signals are then processed for control of industrial robots or similar devices.

Powell, Bradley W.↗
NASA NTRS2008

Guidance, Navigation, and Control System Design in a Mass Reduction Exercise

Early Orion GN&C system designs optimized for robustness, simplicity, and utilization of commercially available components. During the System Definition Review (SDR), all subsystems on Orion were asked to re-optimize with component mass and steady state power as primary design metrics. The objective was to create a mass reserve in the Orion point of departure vehicle design prior to beginning the PDR analysis cycle. The Orion GN&C subsystem team transitioned from a philosophy of absolute 2 fault tolerance for crew safety and 1 fault tolerance for mission success to an approach of 1 fault tolerance for crew safety and risk based redundancy to meet probability allocations of loss of mission and loss of crew. This paper will discuss the analyses, rationale, and end results of this activity regarding Orion navigation sensor hardware, control effectors, and trajectory design.

Crain, Timothy↗