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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 109 records · Page 6
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NASA NTRSDate not supplied

Fire Safety Implications of Preliminary Results from Saffire IV and V Experiments on Large Scale Spacecraft Fires

The spread and growth of flames over large solid fuel samples and their effect on the pressurized spacecraft were studied inside the Cygnus spacecraft while in orbit after departing the International Space Station. These experiments were developed by NASA’s Advanced Exploration Systems Division in the Human Exploration and Operations Mission Directorate. The ignited materials consisted of poly-methyl methacrylate (PMMA), cotton fabric and a cotton/fiberglass fabric blend. The samples were all 40 cm wide and with various lengths ranging from 18 cm for the PMMA samples to 50 cm for the fabrics. The overall results from these tests and their impact on the spacecraft are presented with emphasis on the fire safety implications of the results. The experiments included, a post-fire cleanup system, vehicle internal volume measurements, and transport of acid gases (HCl and HF). Measurements included video images, flame spread rate, flame temperatures and radiant heat output; energy release through oxygen calorimetry; distributed measurements of CO2 concentration and temperature at six locations in the spacecraft; CO2, CO, O2, HF and HCl concentrations; vehicle pressurized volume; and aerosol concentrations. Details of the flame growth and spread are discussed in other papers as are details of the post-fire cleanup system performance. The fire events had a measurable impact on the vehicle pressure, temperature, and carbon dioxide concentration. However, despite having heat release rates up to 10 kW, the average vehicle conditions did not rise to unacceptable levels. The combined results of the experiments provide significant new understanding of the impact of sample and flow duct height on flame spread and growth in addition to an improved perspective of the impact of a fire event on a spacecraft.

micorgravity↗
NASA NTRS1979

Manned remote work station - Safety and rescue considerations

It is noted that due to restrictions of payload and volume limitations of current and projected launch systems, space construction of ultralarge space structures is essential. The present paper discusses the concepts of a key piece of construction equipment needed to support assembly of such large structures. Attention is given to the manned remote work station (MRWS), a universal crew cabin to be used as a construction cherry picker, space crane turret, work station on a construction base rail system, or a free flyer. Concepts and safety and rescue requirements for this spacecraft are delineated for early applications in support of Shuttle operations, as well as applications in support of a mid to late 1980's space construction base. Finally, applications in support of constructing and maintaining a solar power satellite system are covered.

Nathan, C. A.↗
NASA NTRS1993

Fire safety practices in the Shuttle and the Space Station Freedom

The Shuttle reinforces its policy of fire-preventive measures with onboard smoke detectors and Halon 1301 fire extinguishers. The forthcoming Space Station Freedom will have expanded fire protection with photoelectric smoke detectors, radiation flame detectors, and both fixed and portable carbon dioxide fire extinguishers. Many design and operational issues remain to be resolved for Freedom. In particular, the fire-suppression designs must consider the problems of gas leakage in toxic concentrations, alternative systems for single-failure redundancy, and commonality with the corresponding systems of the Freedom international partners. While physical and engineering requirements remain the primary driving forces for spacecraft fire-safety technology, there are, nevertheless, needs and opportunities for the application of microgravity combustion knowledge to improve and optimize the fire-protective systems.

Friedman, Robert↗
NASA NTRS1981

Annual survey of spaceflight safety systems: 11th supplement. Survey period - July 1980-June 1981

Reports in the field of space flight safety applicable to current and future operational space activities which appeared between July 1980 and June 1981 are surveyed. Subjects in the area of flight rescue and safety during launch, on-orbit, reentry and landing phases include the major activities and findings of the first Shuttle test flight, a slidewire system for emergency egress from the Space Shuttle on the launch pad, and the testing of the Spacelab engineering model. In the area of human capabilities and crew roles, attention is given to reports of repairs to the Salyut 6 space station made by a Soyuz crew, and an assessment of weightlessness effects on space worker health and safety. Safety requirements for STS payloads including pressure vessels, and the Orbiter window system and for spacecraft testing are also presented, along with those for a television system to aid in monitoring astronaut extravehicular activities. For the operation of large space structures, reports include EVA equipment for satellite servicing and the safety aspects of connectors used in construction. Finally, attention is given to safety-related criteria in a study of Shuttle interactions with the proposed Space Operations Center.

Brown, N. E.↗
NASA NTRS1987

Photovoltaic power modules for NASA's manned space station

The capability and the safety of manned spacecraft are largely dependent upon reliable electric power systems. Two similar space power systems able to survive the low Earth orbit environment, are being considered for NASA's Manned Space Station (SS), scheduled to begin operation in the mid 1990's. The Space Station Electric Power System (EPS) is composed of Photovoltaic (PV) Power Modules, Solar Dynamic (SD) Power Modules, and the Power Management and Distribution (PMAD) System. One EPS configuration will deliver 37.5 kW of PV based, utility grade, ac power to SS users. A second 75 kWe PV based EPS option is also being considered for SS deployment. The two EPS options utilize common modules and differ only in the total number of PV Power Modules used. Each PV Power Module supplies 18.75 kWe of ac power and incorporates its own energy storage and thermal control. The general requirements and the current preliminary design configuration of the Space Station PV Power Modules are examined.

Tatro, Charles A.↗
NASA NTRS1988

Photovoltaic power modules for NASA's manned Space Station

The capability and the safety of manned spacecraft are largely dependent upon reliable electric power systems. Two similar space power systems able to survive the low earth orbit environment, are being considered for NASA's Manned Space Station (SS), scheduled to begin operation in the mid 1990's. The Space Station Electric Power System (EPS) is composed of Photovoltaic (PV) Power Modules, Solar Dynamic (SD) Power Modules, and the Power Management and Distribution (PMAD) System. One EPS configuration will deliver 37.5 kW of PV based, utility grade, ac power to SS users. A second 75 kWe PV based EPS option is also being considered for SS deployment. The two EPS options utilize common modules and differ only in the total number of PV Power Modules used. Each PV Power Module supplies 18.75 kWe of ac power and incorporates its own energy storage and thermal control. The general requirements and the current preliminary design configuration of the Space Station PV Power Modules are examined.

Tatro, C. A.↗
NASA NTRS1991

HST Mission Operations

The Hubble Space Telescope Project at Goddard Space Flight Center has the overall HST Mission Operations responsibility. In carrying out this responsibility, the functions of mission operations are to fly the spacecraft properly, manage the HST support systems, monitor vehicle health and safety, and conduct the science program in the most efficient manner.

Ryan, Joseph E.↗
NASA NTRS1991

Pegasus (trademark) launch operations and the PegaStar integrated spacecraft bus

The Pegasus air launched space booster, which successfully flew its maiden flight on 5 Apr. 1990, provides the international satellite community with a flexible cost effective means for delivering small payloads into low Earth orbit. The vehicle's simple, robust design and horizontal integration methods ensure maximum reliability and significantly reduce launch base infrastructure requirements. The vehicle's air launched approach and ability to launch over open ocean regions provide unmatched flexibility in launch location and approach used to ensure range safety. The PegaStar integrated spacecraft bus, which complements the Pegasus launch system, can provide a turnkey means for delivering instrument and sensor packages into low Earth orbit and providing extended (5 to 10 year) on orbit operational support. Pegasus and PegaStar are described, including payload interfaces, delivery capability; integration methods, facility and ground support equipment requirements; and typical launch operations.

Mosier, Marty↗
NASA NTRS1994

Formal Methods Demonstration Project for Space Applications

Requirements and design specifications are a high priority candidate for better software engineering techniques. Most hazardous software safety errors found during system integration and test of two NASA spacecraft were the result of requirements discrepancies or interface specifications. The highest density of major defects found through the use of software inspections was during the requirements phase. This was seven times higher than the density of major defects found in code inspections. Requirements errors are between 10 and 100 times more costly to fix at later phases of the software lifecycle than at the requirements phase itself. One study found that early lifecycle errors are the most likely to lead to catastrophic failures.

critical↗
NASA NTRS1989

Galileo and Ulysses missions safety analysis and launch readiness status

The Galileo spacecraft, which will release probes to explore the Jupiter system, was launched in October, 1989 as the payload on STS-34, and the Ulysses spacecraft, which will fly by Jupiter en route to a polar orbit of the sun, is presently entering system-test activity in preparation for an October, 1990 launch. This paper reviews the Galileo and Ulysses mission objectives and design approaches and presents details of the missions' safety analysis. The processes used to develop the safety analysis are described and the results of safety tests are presented.

Cork, M. Joseph↗
NASA NTRSDate not supplied

Applicability of Loads Estimation Techniques Using Sparse Acceleration Sensor Data to Spacecraft Structural Health Monitoring

The use of structural health monitoring systems on spacecraft structures can play a crucial role in ensuring the safety, reliability, and longevity of the structure by gathering and analyzing onboard sensor data. Of specific importance is monitoring for excessive loading at critical interfaces as any off-nominal structural excitations experienced by spacecraft structures can cause early unpredicted high structural life consumption or damage. The availability and cost of flight-certified sensors along with the size of spacecraft structures and allowable payload mass drives the need for a method to estimate loads using sparsely-located sensors. Numerous approaches such as physics-based, statistical learning, and physics-enhanced statistical learning algorithms have gained popularity among structural prognostics applications. However, developing noise-robust prediction models to assess loads and structural life predictions from a sparse multi-sensor data acquisition system can be a challenging task. This paper discusses the evaluation of physics-based versus machine-learning algorithms for predicting loads and structural life at mission critical locations on the spacecraft structure using a finite element loads analysis with the application of simulated noise and noise reduction techniques. To estimate the loads from accelerations, the physics-based algorithm leverages a loads transformation matrix from a Craig-Bampton reduced finite element model. A System Equivalent Reduction Expansion Process (SEREP) and a pseudo-inverse approach are considered to expand from the onboard sensor degrees of freedom to the Craig-Bampton model degrees of freedom. The machine learning algorithm provides a data driven solution/mapping of the sensor accelerations to the loads at the mission critical locations using a high dimensionality analysis. Although these strategies produce comparable loads prediction without noise, the limitations of these strategies with incorporating simulated noise and noise reduction techniques with low signal to noise ratio signals are evaluated. The study demonstrates the immense potential of statistical learning algorithms for sparse structural prognostic models and enhancing signal denoising techniques. These findings also highlight the need for noise-resilient prognostic models and low-noise data acquisition systems onboard spacecraft structures.

Spacecraft Structural Health Monitoring↗
NASA NTRS2009

Spacecraft Thermal Management

In the 21st century, the National Aeronautics and Space Administration (NASA), the Russian Federal Space Agency, the National Space Agency of Ukraine, the China National Space Administration, and many other organizations representing spacefaring nations shall continue or newly implement robust space programs. Additionally, business corporations are pursuing commercialization of space for enabling space tourism and capital business ventures. Future space missions are likely to include orbiting satellites, orbiting platforms, space stations, interplanetary vehicles, planetary surface missions, and planetary research probes. Many of these missions will include humans to conduct research for scientific and terrestrial benefits and for space tourism, and this century will therefore establish a permanent human presence beyond Earth s confines. Other missions will not include humans, but will be autonomous (e.g., satellites, robotic exploration), and will also serve to support the goals of exploring space and providing benefits to Earth s populace. This section focuses on thermal management systems for human space exploration, although the guiding principles can be applied to unmanned space vehicles as well. All spacecraft require a thermal management system to maintain a tolerable thermal environment for the spacecraft crew and/or equipment. The requirements for human rating and the specified controlled temperature range (approximately 275 K - 310 K) for crewed spacecraft are unique, and key design criteria stem from overall vehicle and operational/programatic considerations. These criteria include high reliability, low mass, minimal power requirements, low development and operational costs, and high confidence for mission success and safety. This section describes the four major subsystems for crewed spacecraft thermal management systems, and design considerations for each. Additionally, some examples of specialized or advanced thermal system technologies are presented, which may be enabling to future space missions never before attempted like a crewed mission to Mars.

Hurlbert, Kathryn Miller↗
NASA NTRS2016

Relating MBSE to Spacecraft Development: A NASA Pathfinder

The NASA Engineering and Safety Center (NESC) has sponsored a Pathfinder Study to investigate how Model Based Systems Engineering (MBSE) and Model Based Engineering (MBE) techniques can be applied by NASA spacecraft development projects. The objectives of this Pathfinder Study included analyzing both the products of the modeling activity, as well as the process and tool chain through which the spacecraft design activities are executed. Several aspects of MBSE methodology and process were explored. Adoption and consistent use of the MBSE methodology within an existing development environment can be difficult. The Pathfinder Team evaluated the possibility that an "MBSE Template" could be developed as both a teaching tool as well as a baseline from which future NASA projects could leverage. Elements of this template include spacecraft system component libraries, data dictionaries and ontology specifications, as well as software services that do work on the models themselves. The Pathfinder Study also evaluated the tool chain aspects of development. Two chains were considered: 1. The Development tool chain, through which SysML model development was performed and controlled, and 2. The Analysis tool chain, through which both static and dynamic system analysis is performed. Of particular interest was the ability to exchange data between SysML and other engineering tools such as CAD and Dynamic Simulation tools. For this study, the team selected a Mars Lander vehicle as the element to be designed. The paper will discuss what system models were developed, how data was captured and exchanged, and what analyses were conducted.

Othon, Bill↗
NASA NTRS2013

Autonomous Control of Space Nuclear Reactors

Nuclear reactors to support future robotic and manned missions impose new and innovative technological requirements for their control and protection instrumentation. Long-duration surface missions necessitate reliable autonomous operation, and manned missions impose added requirements for failsafe reactor protection. There is a need for an advanced instrumentation and control system for space-nuclear reactors that addresses both aspects of autonomous operation and safety. The Reactor Instrumentation and Control System (RICS) consists of two functionally independent systems: the Reactor Protection System (RPS) and the Supervision and Control System (SCS). Through these two systems, the RICS both supervises and controls a nuclear reactor during normal operational states, as well as monitors the operation of the reactor and, upon sensing a system anomaly, automatically takes the appropriate actions to prevent an unsafe or potentially unsafe condition from occurring. The RPS encompasses all electrical and mechanical devices and circuitry, from sensors to actuation device output terminals. The SCS contains a comprehensive data acquisition system to measure continuously different groups of variables consisting of primary measurement elements, transmitters, or conditioning modules. These reactor control variables can be categorized into two groups: those directly related to the behavior of the core (known as nuclear variables) and those related to secondary systems (known as process variables). Reliable closed-loop reactor control is achieved by processing the acquired variables and actuating the appropriate device drivers to maintain the reactor in a safe operating state. The SCS must prevent a deviation from the reactor nominal conditions by managing limitation functions in order to avoid RPS actions. The RICS has four identical redundancies that comply with physical separation, electrical isolation, and functional independence. This architecture complies with the safety requirements of a nuclear reactor and provides high availability to the host system. The RICS is intended to interface with a host computer (the computer of the spacecraft where the reactor is mounted). The RICS leverages the safety features inherent in Earth-based reactors and also integrates the wide range neutron detector (WRND). A neutron detector provides the input that allows the RICS to do its job. The RICS is based on proven technology currently in use at a nuclear research facility. In its most basic form, the RICS is a ruggedized, compact data-acquisition and control system that could be adapted to support a wide variety of harsh environments. As such, the RICS could be a useful instrument outside the scope of a nuclear reactor, including military applications where failsafe data acquisition and control is required with stringent size, weight, and power constraints.

Merk, John↗
NASA NTRS2023

Technical Basis Related to the Posture of NASA’s Office of Safety and Mission Assurance for the Launch of Radioactive Material Other than Space Nuclear Systems: Volume 1–Overview of Analysis and Results

NASA has launched and reentered payloads containing radioactive material for over 50 years. The isotopes, their quantity, and their form have varied significantly. The handling of this material prior to its integration into the spacecraft at the launch Center (and after its return to Earth after flight, if applicable) falls under the purview of the Office of the Chief Health and Medical Officer, while after the radioactive material is integrated into the spacecraft at the launch Center, it falls under the purview of the Office of Safety and Mission Assurance’s (OSMA) Nuclear Flight Safety Program. Historically, OSMA concurrence was required for any launch or reentry involving radioactive material. However, OSMA recently revisited this posture due to changes in the Federal policy in this area, and the significant accrued experience. The current report represents the more quantitative study envisioned in the recent change in posture. More specifically, this document addresses the potential risks and other considerations associated with launching small quantities of radioactive material (below the level requiring the Federally-mandated process in National Security Presidential Memorandum- (NSPM-) 20, “Presidential Memorandum on Launch of Spacecraft Containing Space Nuclear Systems” (USG, 2019) to provide the technical basis for when such activities require OSMA concurrence versus notification, as it relates to nuclear flight safety.

Don Helton↗
NASA NTRS2005

NASA's Software Safety Standard

NASA (National Aeronautics and Space Administration) relies more and more on software to control, monitor, and verify its safety critical systems, facilities and operations. Since the 1960's there has hardly been a spacecraft (manned or unmanned) launched that did not have a computer on board that provided vital command and control services. Despite this growing dependence on software control and monitoring, there has been no consistent application of software safety practices and methodology to NASA's projects with safety critical software. Led by the NASA Headquarters Office of Safety and Mission Assurance, the NASA Software Safety Standard (STD-18l9.13B) has recently undergone a significant update in an attempt to provide that consistency. This paper will discuss the key features of the new NASA Software Safety Standard. It will start with a brief history of the use and development of software in safety critical applications at NASA. It will then give a brief overview of the NASA Software Working Group and the approach it took to revise the software engineering process across the Agency.

Ramsay, Christopher M.↗
NASA NTRS2021

Advanced Multimodal Solutions for Information Presentation

High-workload, fast-paced, and degraded sensory environments are the likeliest candidates to benefit from multimodal information presentation. For example, during extra-vehicular activity (EVA) and telerobotic operations, the sensory restrictions associated with such a hostile environment provide a major challenge to maintaining the situation awareness (SA) required for safe operations. In particular, orientation, navigation, and collision avoidance are critical aspects of EVA tasks that need to be addressed to ensure the safety of the crew and the success of the mission. Multimodal displays hold promise to enhance situation awareness and task performance by utilizing different sensory modalities and maximizing their effectiveness based on appropriate interaction between modalities. Multimodal displays will also play an important role for long-duration information systems and will likely begin to be developed in the early phases of cislunar Gateway, and later lunar or Mars transit missions. Information systems are envisioned for LDEMs that require spacecraft with greater crew autonomy and increased dependence on computer-provided information needed to perform routine tasks, as well as time- and safety critical tasks. Such a system will require a single, common interface that is easy to learn and use and accesses key information from all relevant vehicle/habitat systems to enable task performance in both nominal and emergency conditions. Understanding of multimodal display technologies and their interactions will help to inform interface guidelines for LDEMs. The scope of the current report is an analysis of potential multimodal display technologies for long duration missions and, in particular, will focus on their potential role in EVA activities. The review will address multimodal (combined visual, auditory and/or tactile) displays investigated by the National Aeronautics and Space Administration (NASA), industry, and Department of Defense (DoD). It also considers the need for adaptive information systems to accommodate a variety of operational contexts such as crew status (e.g., fatigue, workload level) and task environment (e.g., EVA, habitat, rover, spacecraft). Current approaches to guidelines and best practices for combining modalities for the most effective information displays are also reviewed. Potential issues in developing interface guidelines for LDEMs are briefly considered.

multimodal displays↗
NASA NTRS1971

Pressure control and analysis report: Hydrogen Thermal Test Article (HTTA)

Tasks accomplished during the HTTA Program study period included: (1) performance of a literature review to provide system guidelines; (2) development of analytical procedures needed to predict system performance; (3) design and analysis of the HTTA pressurization system considering (a) future utilization of results in the design of a spacecraft maneuvering system propellant package, (b) ease of control and operation, (c) system safety, and (d) hardware cost; and (4) making conclusions and recommendations for systems design.

Source record↗