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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 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS1995

Design, analysis, and control of a large transport aircraft utilizing selective engine thrust as a backup system for the primary flight control

A study has been conducted to determine the capability to control a very large transport airplane with engine thrust. This study consisted of the design of an 800-passenger airplane with a range of 5000 nautical miles design and evaluation of a flight control system, and design and piloted simulation evaluation of a thrust-only backup flight control system. Location of the four wing-mounted engines was varied to optimize the propulsive control capability, and the time constant of the engine response was studied. The goal was to provide level 1 flying qualities. The engine location and engine time constant did not have a large effect on the control capability. The airplane design did meet level 1 flying qualities based on frequencies, damping ratios, and time constants in the longitudinal and lateral-directional modes. Project pilots consistently rated the flying qualities as either level 1 or level 2 based on Cooper-Harper ratings. However, because of the limited control forces and moments, the airplane design fell short of meeting the time required to achieve a 30 deg bank and the time required to respond a control input.

Gerren, Donna S.↗
NASA NTRS1997

Piloted Simulation Tests of Propulsion Control as Backup to Loss of Primary Flight Controls for a B747-400 Jet Transport

Partial failures of aircraft primary flight control systems and structural damages to aircraft during flight have led to catastrophic accidents with subsequent loss of lives (e.g. DC-10, B-747, C-5, B-52, and others). Following the DC-10 accident at Sioux City, Iowa in 1989, the National Transportation Safety Board recommended 'Encourage research and development of backup flight control systems for newly certified wide-body airplanes that utilize an alternate source of motive power separate from that source used for the conventional control system.' This report describes the concept of a propulsion controlled aircraft (PCA), discusses pilot controls, displays, and procedures; and presents the results of a PCA piloted simulation test and evaluation of the B747-400 airplane conducted at NASA Ames Research Center in December, 1996. The purpose of the test was to develop and evaluate propulsion control throughout the full flight envelope of the B747-400 including worst case scenarios of engine failures and out of trim moments. Pilot ratings of PCA performance ranged from adequate to satisfactory. PCA performed well in unusual attitude recoveries at 35,000 ft altitude, performed well in fully coupled ILS approaches, performed well in single engine failures, and performed well at aft cg. PCA performance was primarily limited by out-of-trim moments.

Bull, John↗
NASA NTRS2005

High-Temperature Polymer Composites Tested for Hypersonic Rocket Combustor Backup Structure

Significant component weight reductions are required to achieve the aggressive thrust-toweight goals for the Rocket Based Combined Cycle (RBCC) third-generation, reusable liquid propellant rocket engine, which is one possible engine for a future single-stage-toorbit vehicle. A collaboration between the NASA Glenn Research Center and Boeing Rocketdyne was formed under the Higher Operating Temperature Propulsion Components (HOTPC) program and, currently, the Ultra-Efficient Engine Technology (UEET) Project to develop carbon-fiber-reinforced high-temperature polymer matrix composites (HTPMCs). This program focused primarily on the combustor backup structure to replace all metallic support components with a much lighter polymer-matrixcomposite- (PMC-) titanium honeycomb sandwich structure.

Sutter, James K.↗
NASA NTRS2004

Human-Rated Space Vehicle Backup Flight Systems

Human rated space vehicles have historically employed a Backup Flight System (BFS) for the main purpose of mitigating the loss of the primary avionics control system. Throughout these projects, however, the underlying philosophy and technical implementation vary greatly. This paper attempts to coalesce each of the past space vehicle program's BFS design and implementation methodologies with the accompanying underlining philosophical arguments that drove each program to such decisions. The focus will be aimed at Mercury, Gemini, Apollo, and Space Shuttle However, the ideologies and implementation of several commercial and military aircraft are incorporated as well to complete the full breadth view of BFS development across the varying industries. In particular to the non-space based vehicles is the notion of deciding not to utilize a BFS. A diverse analysis of BFS to primary system benefits in terms of reliability against all aspects of project development are reviewed and traded. The risk of engaging the BFS during critical stages of flight (e.g. ascent and entry), the level of capability of the BFS (subset capability of main system vs. equivalent system), and the notion of dissimilar hardware and software design are all discussed. Finally, considerations for employing a BFS on future human-rated space missions are reviewed in light of modern avionics architectures and mission scenarios implicit in exploration beyond low Earth orbit.

Davis, Jeffrey A.↗
NASA NTRS2000

Development of a Solid Chlorate Backup Oxygen Delivery System for the International Space Station

The International Space Station (ISS) Program requires that there always be a 45 calendar day contingency supply of breathing oxygen. In the early assembly stages, there is only one flight system, the Russian Solid Fuel Oxygen Generator (SFOG), that can meet that requirement. To better ensure the contingency oxygen supply, the Crew and Thermal Systems Division was directed to develop a flight hardware system that can meet all contingency oxygen requirements for ISS. Such a system, called the Backup Oxygen Candle System (BOCS), has been built and tested. The BOCS consists of 33 chlorate candles, a thermal containment apparatus, support equipment and packaging. The thermal containment apparatus utilizes the O2 produced by the candle as the motive stream in an ejector to passively cool the candle during operation.

Graf, John↗
NASA NTRS2010

Cassini Spacecraft In-Flight Swap to Backup Attitude Control Thrusters

NASA's Cassini Spacecraft, launched on October 15th, 1997 and arrived at Saturn on June 30th, 2004, is the largest and most ambitious interplanetary spacecraft in history. In order to meet the challenging attitude control and navigation requirements of the orbit profile at Saturn, Cassini is equipped with a monopropellant thruster based Reaction Control System (RCS), a bipropellant Main Engine Assembly (MEA) and a Reaction Wheel Assembly (RWA). In 2008, after 11 years of reliable service, several RCS thrusters began to show signs of end of life degradation, which led the operations team to successfully perform the swap to the backup RCS system, the details and challenges of which are described in this paper. With some modifications, it is hoped that similar techniques and design strategies could be used to benefit other spacecraft.

Bates, David M.↗
NASA NTRSDate not supplied

Data Definition Management for Orion Backup Flight Software

The NASA developed Core Flight System (cFS) is a reusable software architecture that has been used on multiple spaceflight missions. Missions using cFS can reuse code from other missions, as well as leverage deployment to similar computer architectures. The Orion Backup Flight Software (BFS) team selected cFS as the architecture to be used on the program, and this presentation will describe some design choices we made, and the consequences of those decisions.

CFS↗
NASA NTRS2004

Trajectory design for the Genesis backup orbit and proposed extended mission

In September 2004, the Genesis spacecraft will return to Earth with its collection of solar wind samples. If for some reason there are any difficulties with returning the samples to Earth during the nominal entry sequence, a contingency plan is in place for a second chance at a successful recovery. This paper will detail the processes used to generate possible backup trajectories, and provide a comparison of the contingency options examined through the course of the study.

Chung, Min-Kun J.↗
NASA NTRSDate not supplied

Orion Backup Flight Software

Orion Backup Flight Software (BFS) is a joint NASA/Lockheed Martin effort designed to prevent the loss of the Orion crew. BFS will only take over in the event the primary flight software (PFSW) fails to operate properly due to either hardware or software failures. Since the PFSW runs identical software on identical hardware, it is conceivable that a single issue could simultaneously bring down all the PFSW. To minimize the likelihood BFS would be affected by the same issue, BFS was specifically designed to be as different as possible from PFSW: BFS runs on different hardware, a separate operating system, a different compiler, does not share software libraries, and is written by a different team of programmers. This presentation will provide a high-level overview of the Artemis missions and the Orion vehicle, as well as provide additional details of the BFS system (including how BFS is different than the PFSW). The overall BFS capability evolution and timeline (milestones reached as well as work remaining) through the Artemis III mission will be discussed. Additionally, the verification and validation plans for BFS will be presented, describing how we ensure that only validated configuration data is loaded onto the flight vehicle. Finally, the presentation will close with lessons learned and future plans for Orion BFS.

Orion↗
NASA NTRSDate not supplied

Orion Backup Flight Software (BFS)

Orion Backup Flight Software (BFS) is a joint NASA/Lockheed Martin effort designed to prevent the loss of the Orion crew. BFS will only take over in the event the primary flight software (PFSW) fails to operate properly due to either hardware or software failures. Since the PFSW runs identical software on identical hardware, it is conceivable that a single issue could simultaneously bring down all the PFSW. To minimize the likelihood BFS would be affected by the same issue, BFS was specifically designed to be as different as possible from PFSW: BFS runs on different hardware, a separate operating system, a different compiler, does not share software libraries, and is written by a different team of programmers. This presentation will provide a high-level overview of the Artemis missions and the Orion vehicle, as well as provide additional details of the BFS system (including how BFS is different than the PFSW). The overall BFS capability evolution and timeline (milestones reached as well as work remaining) through the Artemis III mission will be discussed. Additionally, the verification and validation plans for BFS will be presented, describing how we ensure that only validated configuration data is loaded onto the flight vehicle. Finally, the presentation will close with lessons learned and future plans for Orion BFS.

CFS↗
NASA NTRSDate not supplied

Evaluation of the KOKEE12M/ONSA13NE Baseline as a KOKEE12M/WETTZ13S Backup

USNO's IERS Rapid Service/Prediction Center (RS/PC) uses the KOKEE12M/WETTZ13S (K2/Ws) baseline for its combination solutions. It would be useful for the RS/PC to be able to use backup baselines in case K2 or Ws is not available. While Ws was undergoing repair in late 2022 through early 2023, ONSA13NE (Oe) replaced Ws to provide immediate UT1 for IVS Analysis Center products but also to begin building a data set for the RS/PC to eventually use to ``characterize'' (assess and approve) the K2/Oe baseline for use in its solutions. The RS/PC needs 60 sessions to be able to characterize a baseline, and the data from the repair period provided 58 sessions, with three additional sessions being observed later. Here we evaluate the K2/Oe baseline to see if it is a viable candidate for submission to the RS/PC for characterization. We evaluate the K2/Oe baseline itself and also compare the K2/Oe baseline to the K2/Ws baseline.

VLBI↗
NASA NTRS1998

The ASTER Emergency Backup System

This paper discusses the international aspect of the ASTER project by specifying data flow among Japan, the EDC DAAC, the JPL SCF, The Goddard Space Flight Center (GSFC), and the ASTER Science Team.

ASTER↗
NASA NTRS1971

The quasi-inertial and wide-deadband modes as backup attitude options for the Skylab mission

The quasi-inertial (QI) and wide deadband (WDB) modes were investigated as alternatives to the solar inertial (SI) mode in case two control moment gyros fail during the Skylab mission. Both modes provide a substantial reduction in propellant requirements from the solar interial hold requirement with either the orbital assembly/thruster attitude control system or service module reaction control system. Spacecraft motion in the QI mode is produced by a command rate and results in a small amplitude oscillation (17 deg, maximum) about the SI orientation. In the WDB mode a somewhat similar, but larger amplitude motion (35 deg maximum) about the SI orientation is developed by appropriate choice of controller deadbands and switch line slopes.

Elrod, B. D.↗
NASA NTRS1972

The Backup-Gilbert method and its application to the electrical conductivity problem

The theory of Backus and Gilbert gives a technique for solving the general linear inverse problem. Observational error and lack of data are shown to reduce the reliability of the solution in different ways: the former introduces statistical uncertainties in the model, while the latter smooths out the detail. Precision can be improved by sacrificing resolving power, and vice versa, so that some compromise may be made between the two in choosing the best model. Nonlinear inverse problems can be brought into the domain of the theory by linearizing about a typical solution. The inverse problem of electrical conductivity in the mantle is used to illustrate the Backus-Gilbert technique; an example of the tradeoff diagram is given.

Parker, R. L.↗
NASA NTRS1976

A radar study of the backup Martian landing sites

The Goldstone radar system at DSS 14 was used to probe the Martian surface at 8495 MHz in a narrow strip between -6 deg and -2 deg latitude. The Viking C landing sites lie in this strip, and their altitudes, rms surface slope, and reflectivity are presented.

Downs, G. S.↗