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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 415 records · Page 23
All sourcesNASA NTRSDOE OSTI
NASA NTRS1999

Martian Aerocapture Terminal Point Guidance: A Reference Path Optimization Study

An effective method of terminal point guidance is to employ influence coefficients, which are solved from a set of differential equations adjoint to the linearized perturbations of the equations of motion about a reference trajectory. Hence, to optimize this type of guidance, one must first optimize the reference trajectory that the guidance is based upon. This study concentrates on various methods to optimize a reference trajectory for a Martian aerocapture maneuver, including a parametric analysis and first order gradient method. Resulting reference trajectories were tested in separate 2000 6-DOF Monte Carlo runs, using the Atmospheric Guidance Algorithm Testbed for the Mars Surveyor Program 2001 (MSP '01) Orbiter. These results were compared to an August 1998 study using the same terminal point control guidance algorithm and simulation testbed. Satisfactory improvements over the 1998 study are amply demonstrated.

Ro, Theodore U.↗
NASA NTRS2009

A Flight Dynamics Perspective of the Orion Pad Abort One Flight Test

The Orion Crew Exploration Vehicle is America s next generation of human rated spacecraft. The Orion Launch Abort System will take the astronauts away from the exploration vehicle in the event of an aborted launch. The pad abort mode of the Launch Abort System will be flight-tested in 2009 from the White Sands Missile Range in New Mexico. This paper examines some of the efforts currently underway at the NASA Dryden Flight Research Center by the Controls & Dynamics group in preparation for the flight test. The concept of operation for the pad abort flight is presented along with an overview of the guidance, control and navigation systems. Preparations for the flight test, such as hardware testing and development of the real-time displays, are examined. The results from the validation and verification efforts for the aerodynamic and atmospheric models are shown along with Monte Carlo analysis results.

Idicula, Jinu↗
NASA NTRS1990

A manned maneuvering unit proximity operations planning and flight guidance display and control system

This task concerns the design, development, testing, and evaluation of a new proximity operations planning and flight guidance display and control system for manned space operations. A forecast, derivative manned maneuvering unit (MMU) was identified as a candidate for the application of a color, highway-in-the-sky display format for the presentation of flight guidance information. A silicon graphics 4D/20-based simulation is being developed to design and test display formats and operations concepts. The simulation includes the following: (1) real-time color graphics generation to provide realistic, dynamic flight guidance displays and control characteristics; (2) real-time graphics generation of spacecraft trajectories; (3) MMU flight dynamics and control characteristics; (4) control algorithms for rotational and translational hand controllers; (5) orbital mechanics effects for rendezvous and chase spacecraft; (6) inclusion of appropriate navigation aids; and (7) measurement of subject performance. The flight planning system under development provides for: (1) selection of appropriate operational modes, including minimum cost, optimum cost, minimum time, and specified ETA; (2) automatic calculation of rendezvous trajectories, en route times, and fuel requirements; (3) and provisions for manual override. Man/machine function allocations in planning and en route flight segments are being evaluated. Planning and en route data are presented on one screen composed of two windows: (1) a map display presenting a view perpendicular to the orbital plane, depicting flight planning trajectory and time data attitude display presenting attitude and course data for use en route; and (2) an attitude display presenting local vertical-local horizontal attitude data superimposed on a highway-in-the-sky or flight channel representation of the flight planned course. Both display formats are presented while the MMU is en route. In addition to these displays, several original display elements are being developed, including a 3DOF flight detector for attitude commanding, a different flight detector for translation commands, and a pictorial representation of velocity deviations.

Gershzohn, Gary R.↗
NASA NTRS1998

Recent Events in Guidance, Navigation, and Control

This article summarizes the highlights of recent events and developments in guidance, navigation, and control in space, aircraft, and weapons. Information for the article was collected from other NASA Centers, DoD, and industry. All information collected was previously cleared by the originating organizations. Information for the article was also gathered from Aviation Week and Space Technology, Space News, and similar sources.

Polites, Michael E.↗
NASA NTRS2015

Post-Flight Analysis of the Guidance, Navigation, and Control Performance During Orion Exploration Flight Test 1

The first test flight of the Orion Multi-Purpose Crew Vehicle presented additional challenges for guidance, navigation and control as compared to a typical re-entry from the International Space Station or other Low Earth Orbit. An elevated re-entry velocity and steeper flight path angle were chosen to achieve aero-thermal flight test objectives. New IMU's, a GPS receiver, and baro altimeters were flight qualified to provide the redundant navigation needed for human space flight. The guidance and control systems must manage the vehicle lift vector in order to deliver the vehicle to a precision, coastal, water landing, while operating within aerodynamic load, reaction control system, and propellant constraints. Extensive pre-flight six degree-of-freedom analysis was performed that showed mission success for the nominal mission as well as in the presence of sensor and effector failures. Post-flight reconstruction analysis of the test flight is presented in this paper to show whether that all performance metrics were met and establish how well the pre-flight analysis predicted the in-flight performance.

Barth, Andrew↗
NASA NTRS1980

Noise Protection

Environmental Health Systems puts forth an increasing effort in the U.S. to develop ways of controlling noise, particularly in industrial environments due to Federal and State laws, labor union insistence and new findings relative to noise pollution impact on human health. NASA's Apollo guidance control system aided in the development of a noise protection product, SMART. The basis of all SMART products is SMART compound a liquid plastic mixture with exceptional energy/sound absorbing qualities. The basic compound was later refined for noise protection use.

Source record↗
NASA NTRS1971

Space shuttle guidance, navigation and control design equations. Volume 4: Deorbit and atmospheric operations

A baseline set of equations which fulfill the computation requirements for guidance, navigation, and control of the space shuttle orbiter vehicle is presented. All shuttle mission phases are covered from prelaunch through landing/rollout. The spacecraft flight mode and the aircraft flight mode are addressed. The baseline equations may be implemented in a single guidance, navigation, and control computer or may be distributed among several subsystem computers.

Cox, K. J.↗
NASA NTRS2011

Guidance, Navigation, and Control Program

The Rendezvous and Proximity Operations Program (RPOP) is real-time guidance, navigation, and control (GN&C) domain piloting-aid software that provides 3D Orbiter graphics and runs on the Space Shuttle's Criticality-3 Payload and General Support Computer (PGSC) in the crew cockpit. This software provides the crew with Situational Awareness during the rendezvous and proximity operations phases of flight. RPOP can be configured from flight to flight, accounting for mission-specific flight scenarios and target vehicles, via initialization load (I-load) data files. The software provides real-time, automated, closed-loop guidance recommendations and the capability to integrate the crew s manual backup techniques. The software can bring all relative navigation sensor data, including the Orbiter's GPC (general purpose computer) data, into one central application to provide comprehensive situational awareness of the rendezvous and proximity operations trajectory. RPOP also can separately maintain trajectory estimates (past, current, and predicted) based on certain data types and co-plot them, in order to show how the various navigation solutions compare. RPOP s best estimate of the relative trajectory is determined by a relative Kalman filter processing data provided by the sensor suite s most accurate sensor, the trajectory control sensor (TCS). Integrated with the Kalman filter is an algorithm that identifies the reflector that the TCS is tracking. Because RPOP runs on PC laptop computers, the development and certification lifecycles are more agile, flexible, and cheaper than those that govern the Orbiter FSW (flight software) that runs in the GPC. New releases of RPOP can be turned around on a 3- to 6-month template, from new Change Request (CR) to certification, depending on the complexity of the changes.

Hinkel, Heather↗
NASA NTRS2005

The X-43A Hyper-X Mach 7 Flight 2 Guidance, Navigation, and Control Overview and Flight Test Results

The objective of the Hyper-X program was to flight demonstrate an airframe-integrated hypersonic vehicle. On March 27, 2004, the Hyper-X program team successfully conducted flight 2 and achieved all of the research objectives. The Hyper-X research vehicle successfully separated from the Hyper-X launch vehicle and achieved the desired engine test conditions before the experiment began. The research vehicle rejected the disturbances caused by the cowl door opening and the fuel turning on and off and maintained the engine test conditions throughout the experiment. After the engine test was complete, the vehicle recovered and descended along a trajectory while performing research maneuvers. The last data acquired showed that the vehicle maintained control to the water. This report will provide an overview of the research vehicle guidance and control systems and the performance of the vehicle during the separation event and engine test. The research maneuvers were performed to collect data for aerodynamics and flight controls research. This report also will provide an overview of the flight controls related research and results.

Bahm, Catherine↗
NASA NTRS1999

1999 Guidance, Navigation, and Control Highlights

This article summarizes the highlights of recent events and developments in guidance, navigation, and control in space, aircraft, and weapons. This article is about 1,200 words long. Information for the article was collected from other NASA Centers, DoD, and industry. All information was previously cleared by the originating organizations. Information for the article was also gathered from Aviation Week and Space Technology, Space News, and similar sources.

Polites, Michael E.↗
NASA NTRS1998

1998 Guidance, Navigation, and Control Highlights

This article summarizes the highlights of recent events and developments in guidance, navigation, and control in space, aircraft, and weapons. The article is about 1,200 words long. Information for the article was collected from other NASA Centers, DoD, and industry. All information collected was previously cleared by the originating organizations. Information for the article was also gathered from Aviation Week and Space Technolo2y, Space News, and similar sources.

Polites, Michael E.↗
NASA NTRS1999

Recent Events in Guidance, Navigation, and Control Highlights

This article summarizes the highlights of recent events and developments in guidance, navigation, and control in space, aircraft, and weapons. This article is about 3,600 words long. Information for the article was collected from other NASA Centers, DoD, and industry. All information was previously cleared by the originating organizations. Information for the article was also gathered from Aviation Week and Space Technology, Space News, and similar sources.

Polites, Michael E.↗
NASA NTRS2000

2000 Guidance, Navigation, and Control Highlights

This article summarizes the highlights of recent events and developments in guidance, navigation, and control in space, aircraft, and weapons. This article is about 1,200 words long. Information for the article was collected from other NASA centers, DoD, and industry. All information was previously cleared by the originating organizations. Information for the article was also gathered from Aviation Week and Space Technology, Space News, and similar sources.

Polites, Michael E.↗
NASA NTRS1987

Quasi-steady flight to quasi-steady flight transition in a windshear - Trajectory guidance

The control (via the angle of attack) of the vertical flight of an aircraft taking off at maximum power in a horizontal wind shear with downdraft is investigated analytically. Optimal trajectories to recover the initial path inclination or to recover quasi-steady flight (the relative values of the velocity, path inclination, and angle of attack) are derived using a Chebyshev approach and shown to be nearly identical in the shear but divergent after the shear. These results are then applied to construct a trajectory-guidance control comprising a variable-gamma guidance scheme for the shear trajectory, a constant-gamma guidance scheme for the immediate postshear trajectory, and a constant-rate-of-climb guidance scheme for the aftershear trajectory. Numerical results demonstrating the near-optimal performance of the control are presented in tables and graphs.

Miele, A.↗
NASA NTRS1995

An Advanced Fly-By-Wire Flight Control System for the RASCAL Research Rotorcraft: Concept to Reality

Design features of a new fly-by-wire flight control system for the Rotorcraft-Aircrew Systems Concepts Airborne Laboratory (RASCAL) are described. Using a UH-60A Black Hawk helicopter as a baseline vehicle, the RASCAL will be a flying laboratory capable of supporting the research requirements of major NASA and Army guidance, control, and display research programs. The paper describes the research facility requirements of these pro-rams and the design implementation of the research flight control system (RFCS), with emphasis on safety-of-flight, adaptability to multiple requirements and performance considerations.

Rediess, Nicholas A.↗
NASA NTRS2021

Stochastic Guidance of Buoyancy Controlled Vehicles under Ice Shelves using Ocean Currents

We propose a novel technique for guidance ofbuoyancy-controlled vehicles in uncertain under-ice ocean flows.In-situ melt rate measurements collected at the grounding zoneof Antarctic ice shelves, where the ice shelf meets the underlyingbedrock, are essential to constrain models of future sea levelrise. Buoyancy-controlled vehicles, which control their verticalposition in the water column but have no means of horizontalpropulsion, offer an affordable and reliable platform for suchin-situ data collection. However, reaching the grounding zonerequires vehicles to traverse tens of kilometers under the iceshelf, with approximate position knowledge and no meansof communication, in highly variable and uncertain oceancurrents. To address this challenge, we propose a partiallyobservable MDP approach that exploits model-based knowledgeof the under-ice currents and, critically, of their uncertainty,to synthesize effective guidance policies. The approach usesapproximate dynamic programming to model uncertainty inthe currents, and QMDP to address localization uncertainty.Numerical experiments show that the policy can deliver upto 88.8% of underwater vehicles to the grounding zone – a33% improvement compared to state-of-the-art guidance techniques, and a 262% improvement over uncontrolled drifters.Collectively, these results show that model-based under-iceguidance is a highly promising technique for exploration ofunder-ice cavities, and has the potential to enable cost-effectiveand scalable access to these challenging and rarely observed environments.

Clark, Evan B.↗