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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 163 records · Page 9
All sourcesNASA NTRSDOE OSTI
NASA NTRS2021

Astro-biological Exploration of Ocean Worlds, Enabled by an RPS Inside a Pressure Vessel

Exploring Ocean and Ice Worlds could help us to understand the origin and evolution of life in the universe. In our solar system we have identified six Ocean and Ice Worlds, namely Earth, Europa, Ganymede, Callisto, Enceladus, and Titan. Other potential targets include Dione, Triton, and Pluto. As documented in the Planetary Decadal Survey [1] and the NASA Roadmap to Ocean Worlds [2], these worlds are compelling science destinations, with oceans situated below their tens of kilometers thick ice shells. To reach them we need a new exploration paradigm with novel technological solutions. Key technological challenges revolve around the power for the probe and for melting, as well as protecting the payload against the extreme environments, including high pressure, low temperature, corrosion, and radiation. Far away from the Sun, and melted into the ice, we may only rely on long-lived internal power generation. Radioisotope Power Systems (RPS) with either static or dynamic conversion, utilizing the heat of decaying Plutonium-238, could be good candidates. We need suitable payloads that are protected and could survive the extreme environments, as well as enabling power and thermal systems for melting through the ice shield and to swim in the ocean below the ice. RPS could support the probe’s instruments and sub-systems, as well as provide a heat source for melting the ice while keeping the components at operating temperatures. Mitigating the external pressure while immersing inside the ice shell, and in the ocean, would require a new RPS design that operates inside a Pressure Vessel. In our paper, we will discuss general mission architecture trades and the sizing of a next generation RPS housed in a pressure vessel, broadly applicable to any of the Ocean Worlds satellites of interest. Through a technology focused approach, we address interconnected design and mission architecture aspects, including considerations for: the RPS and the Pressure Vessel; extreme environmental constraints; g-load tolerance; power and thermal systems sizing for science measurements; spacecraft operations through all mission phases; subsurface mobility; and planetary protection. The findings will inform the science community on instrument accommodation possibilities; the mission planning community on possible mission concepts; and the RPS development community on the science driven technology considerations.

Donitz, Benjamin P.↗
NASA NTRS2022

Spacecraft Passivation - An Overview of Requirements, Principles, and Practices as Applied to Spacecraft Pressure Vessels

Explosions, collisions, and other catastrophic breakups of launch vehicle orbital stages and satellites continue to be major contributors to the generation of orbital debris. Both launch vehicles and payload satellites typically have several types of stored energy sources on board, any of which might result in energetic breakups and the creation of debris after their mission has ended. These energy sources include propulsion systems, pressure vessels, reaction wheels, control moment gyros, heat pipes, and power systems. NASA, ESA, JAXA and other space-faring organizations have requirements in place to limit the growth of the orbital debris population by passivating space vehicles that remain in orbit after their missions have ended. In this paper, we review current spacecraft passivation philosophies and principles, as well as how those principles have been applied in practice. In particular, we focus on how NASA programs have addressed spacecraft passivation. We begin by considering and reviewing general passivation requirements, with specific emphasis on pressure vessel passivation. We then discuss passivation approaches used in several recent NASA missions as well as some practical considerations in spacecraft passivation, and conclude by providing some summary guidelines regarding what may be considered acceptable (reduced) pressure level targets (depending on the tank commodity and the type of propulsion system) that could allow the pressure vessel to be considered in a passivated state.

Scott Hull↗
NASA NTRS2017

Analysis by NASA's VESGEN Software of Retinal Blood Vessels in Human Subjects Undergoing Head-Down Tilt During 70-Day Bed Rest

Significant risks for visual impairment associated with increased intracranial pressure (VIIP) are incurred by microgravity spaceflight, especially long-duration missions [1]. We hypothesize that microgravity-induced fluid shifts result in pathological changes within blood vessels of the retina that precede development of visual and other ocular impairments. Potential contributions of retinal vascular remodeling to VIIP etiology are therefore being investigated for two studies in 30deg infrared (IR) Heidelberg Spectralis(Registered Trademark) images with NASA's innovative VESsel GENeration Analysis (VESGEN) software [2,3]. The retrospective studies include: (1) before, during and after (pre, mid and post) 6º head-down tilt (HDT) in human subjects during 70 days of bed rest, and (2) before and after missions to the International Space Station (ISS) by U.S. crew members. Results for both studies are almost complete. A preliminary example for HDT is described below.

Microgravity↗
NASA NTRS2023

Passivation of Spacecraft Pressure Vessels: Some Comments on Requirements, Principles, and Practices

Many space-faring organizations have requirements to limit the growth of orbital debris by passivating spacecraft that remain in orbit after mission end. These requirements state that a stored energy devices are to be fully depleted at the end of a spacecraft’s useful life. Spacecraft designs not able to comply with those requirements use a so-called “soft passivation” option. This report presents the results of two studies aimed at better understanding spacecraft pressure vessel passivation state-of-the-art. They summarize current practices and principles of pressure vessel passivation and present an approach that can be used to show that spacecraft propulsion system passivation has been achieved.

Spacecraft Passivation↗
NASA NTRS1968

Decomposition vessel

Stainless steel crucible-shaped vessel permits rapid decomposition of silicates and other refractory compounds by acids at relatively low temperatures. The vessel is lined with tetrafluoroethylene fluorocarbon resin and sealed by a sheet of the same material retained in a stainless steel screw cap.

Bernas, B.↗
NASA NTRS1972

Overflow sensor for cryogenic-fluid vessels

Overflow sensor for cryogenic fluid vessels has been designed by winding electrical resistance element on porous tubular coil form. Form is positioned in overflow vent of cryogenic fluid vessel where it can differentiate vapor from liquid at same temperature.

Tener, W. M.↗
NASA NTRS1973

Large boron--epoxy filament-wound pressure vessels

Advanced composite material used to fabricate pressure vessel is prepeg (partially cured) consisting of continuous, parallel boron filaments in epoxy resin matrix arranged to form tape. To fabricate chamber, tape is wound on form which must be removable after composite has been cured. Configuration of boron--epoxy composite pressure vessel was determined by computer program.

Jensen, W. M.↗
NASA NTRS1972

Glass Fiber Reinforced Metal Pressure Vessel Design Guide

The Engineering Guide presents curves and general equations for safelife design of lightweight glass fiber reinforced (GFR) metal pressure vessels operating under anticipated Space Shuttle service conditions. The high composite vessel weight efficiency is shown to be relatively insensitive to shape, providing increased flexibility to designers establishing spacecraft configurations. Spheres, oblate speroids, and cylinders constructed of GFR Inconel X-750, 2219-T62 aluminum, and cryoformed 301 stainless steel are covered; design parameters and performance efficiencies for each configuration are compared at ambient and cryogenic temperature for an operating pressure range of 690 to 2760 N/sq cm (1000 to 4000 psi). Design variables are presented as a function of metal shell operating to sizing (proof) stress ratios for use with fracture mechanics data generated under a separate task of this program.

Landes, R. E.↗
NASA NTRS1972

Fracture and crack growth resistance studies of 304 stainless steel weldments relating to retesting of cryogenic vessels

Fracture and crack growth resistance characteristics of 304 stainless steel alloy weldments as relating to retesting of cryogenic vessels were examined. Welding procedures were typical of those used in full scale vessel fabrication. Fracture resistance survey tests were conducted in room temperature air, liquid nitrogen and liquid hydrogen. In air, both surface-flawed and center-cracked panels containing cracks in weld metal, fusion line, heat-affected zone, or parent metal were tested. In liquid nitrogen and liquid hydrogen, tests were conducted using center-cracked panels containing weld centerline cracks. Load-unload, sustained load, and cyclic load tests were performed in air or hydrogen gas, liquid nitrogen, and liquid hydrogen using surface-flawed specimens containing weld centerline cracks. Results were used to evaluate the effectiveness of periodic proof overloads in assuring safe and reliable operation of over-the-road cryogenic dewars.

Hall, L. R.↗
NASA NTRS1972

Reliability of composite vessels and proof testing.

The reliability of anisotropic structures is formulated with the aid of the yield and fracture criteria, on the basis of recent studies of composite rocket motor cases in a state of plane stress. The vessel reliability is estimated in terms of the safety factor, thus permitting a rational interpretation of the design safety factor in terms of the vessel relability. The formulation is consistent with the finite element approach, and is being coded into a computer program for practical design evaluation.

Yang, J.-N.↗
NASA NTRS1973

Fracture mechanics technology for optimum pressure vessel design.

A technique has been developed to design a maximum efficiency reliable pressure vessel of given geometry and service life. The technique for ensuring reliability of the minimum weight vessel relies on the application of linear elastic fracture mechanics and fracture mechanics concepts. The resultant design incorporates potential fatigue and stress corrosion crack extension during service of a worst case initial flaw. Maximum stress for safe life is specified by the design technique, thereby minimizing weight. Ratios of pressure and toughness parameters are employed to avoid arbitrary specification of design stress level which would lead to a suboptimum design.

Bjeletich, J. G.↗
NASA NTRS1974

Light-weight spherical submergence vessel

Design vessel with very low thickness-to-radius ratio to obtain low weight, and fabricate it with aid of precision tracer-lathe to limit and control imperfections in spherical shape. Vessel is thin-walled, spherical, monocoque shell constructed from hemispheres joined with sealed and bolted meridional flange.

Baker, I.↗
NASA NTRS1973

Evaluation of polyimide/glass fiber composites for construction of light weight pressure vessels for cryogenic propellants

The application of polyimide resin as a matrix for glass filament-wound thin metal-lined pressure vessels was studied over a temperature range of (minus) 320 to 600 F. Keramid 601 polyimide was found to perform quite well over the entire range of temperature. Hoop stress values of 425 ksi were determined at 75 F which is equivalent to epoxy resin in similar structures. At -320 and 600 F, 125 and 80% of this strength was retained. Thermal ageing at 500 F for up to 50 hours was studied with severe reduction in strength, but there is evidence that this reduction could be improved. Another polyimide resin studied was P10PA which was found to have processing characteristics inappropriate for filament-winding. NOL ring tensile and shear data was determined from both resins with S-glass. Pressure vessel design, fabrication and test procedures are described in detail.

Petker, I.↗