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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 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

Complex permittivity measurements during high temperature recycling of space shuttle antenna window and dielectric heat shield materials

The research performed and the data obtained on candidate space shuttle antenna window and heat shield materials are presented. The measurement technique employs a free-space focused beam microwave bridge for obtaining RF transmission data, and a device which rotates a sample holder which is heated on one side by natural gas-air flames. The surface temperature of each sample is monitored by IR pyrometry; embedded and rear surface thermocouples are also used in obtaining temperature data. The surface of the sample undergoing test is subjected to approximately the same temperature/time profile that occurs at a proposed antenna position on the space shuttle as it re-enters. The samples are cycled through ten of these temperature profiles to determine the recycling effects. Very little change was noted in the materials due to the recycling.

Bassett, H. L.↗
NASA NTRS1985

Investigation of CCD-digicon detector system characteristics

The reported investigation was undertaken with the aim to develop state-of-the-art detector technology for use in astronomical observations. Basic properties of the Digicon concept are to be extended to the two-dimensional capabilities of CCDs. The basic CCD-Digicon tube configuration utilizes a thinned, backside-illuminated CCD in place of the linear, discrete diode array at the back end of a windowed space telescope (ST) design Digicon tube. It is pointed out that the detector system built around the considered device promises to exhibit high photometric accuracy in combination with large numbers of uniform independent resolution elements. Potential applications include space astronomy missions with capability for observations extending into the extreme ultraviolet spectral region. Attention is given to continuing investigations into the characteristics of CCD response to backside photoelectron bombardment, taking into account the development of charge pulse centroiding readout techniques in combination with magnetic deflection substepping.

Hier, R. G.↗
NASA NTRS2008

In Situ Analysis of Martian Phyllosilicates Using the Chemin Minerological Instrument on Mars Science Laboratory

The CheMin minerological instrument on Mars Science Laboratory (MSL'09) [1] will return quantitive Xray diffraction data (XRD) and quantative X-ray fluorescence data (XRF;14<Z<92) from scooped soil samples and drilled rock powders collected from the Mars surface. Samples of 45-65 mm 3 from material sieved to less than 150 micrometers will be delivered through a funnel to one of 27 reusable sample cells (five additional cells on the sample wheel contain diffraction of fluorescence standards). Sample cells are 8-mm diamater discs with 7-micrometer thick Mylar or Kapton windows spaced 170 micrometers apart. Within this volume, the sample is shaken by piezoelectric vibration at sonic frequencies, causing the powder to flow past a narrow, collimated -ray beam in random orientation can be obtained even from minnerals exhibiting strong preferred orientation such as phylosilicates.

Blake, David F.↗
NASA NTRS2004

Far-Infrared Space Interferometers: Future Windows on Star and Planet Formation

Far-IR space interferometers will provide observational access to a spectral region containing many important cooling and diagnostic spectral lines and the bulk of the thermal emission from dust at angular scales critical to advancing our understanding of the star and planet formation process. We will describe concepts for the Space Infrared Interferometric Telescope (SPIRIT) and the Submillimeter Probe of the Evolution of Cosmic Structure (SPECS). Both of these candidate NASA missions are imaging and spectral Michelson interferometers operating in the wavelength range -40 - 800 microns. SPIRIT, which could be launched in a decade as a NASA Origins Probe, is built on a deployable boom and has a maximum baseline length of -30 - 50 m, yielding sub-arcsecond resolution in the far-IR. SPIRIT will thus provide far-IR/sub-mm measurements complementary to the near- and mid-IR measurements obtainable with the James Webb Space Telescope (JWST), and well matched to JWST observations in angular resolution. Ultimately SPECS, a NASA Vision Mission, will use formation flying to attain baseline lengths up to 1 km, and thus angular resolution comparable to that of the Hubble Space Telescope and the Atacama Large Millimeter Array. We will report preliminary results of the NASA-sponsored SPIRIT and SPECS mission studies, which are now underway.

Leisawitz, David↗
NASA NTRS1997

Multi-Window Controllers for Autonomous Space Systems

Multi-window controllers select between elementary linear controllers using nonlinear windows based on the amplitude and frequency content of the feedback error. The controllers are relatively simple to implement and perform much better than linear controllers. The commanders for such controllers only order the destination point and are freed from generating the command time-profiles. The robotic missions rely heavily on the tasks of acquisition and tracking. For autonomous and optimal control of the spacecraft, the control bandwidth must be larger while the feedback can (and, therefore, must) be reduced.. Combining linear compensators via multi-window nonlinear summer guarantees minimum phase character of the combined transfer function. It is shown that the solution may require using several parallel branches and windows. Several examples of multi-window nonlinear controller applications are presented.

Lurie, B, J.↗
NASA NTRS1990

Attitude-dependent launch window analysis for the Hubble Space Telescope Mission

Launch window analysis for Space Shuttle missions determines the launch times which will ensure that all payload and Shuttle requirements for the mission are met. Attitude and pointing analysis determines Shuttle Orbiter attitudes that meet various communication, viewing, and thermal requirements for the Orbiter and its payloads. Historically, launch window analysis and attitude and pointing analysis for Shuttle missions have been done separately, without directly influencing each other. However, methods have been developed to consider simultaneously dependencies between launch window and attitude and pointing requirements if they arise. These methods were developed from the launch window analysis for STS-31, the Hubble Space Telescope (HST) deployment mission. To release the HST, the Orbiter attitude had to remain inertially fixed while pointing the HST at the Sun. The Orbiter release attitude and the HST release time were determined from the position of the Sun and varied with launch time and launch date. The launch window analysis for STS-31 centered on how to determine the range of launch times for a given launch date that would allow the Shuttle to release the HST and simultaneously satisfy communication, attitude, and lighting requirements for the deployment operations. Discussed here are how the HST deployment requirements determined the launch window and how the Orbiter release attitude affected the launch window.

Lenio, James A.↗
NASA NTRS1986

Space Shuttle standard launch window

To maximize the efficiency of the Space Transportation System as a shared cargo launch system and to enhance the mixability and launch opportunities for payloads carried on the Space Shuttle, the National Aeronautics and Space Administration has developed a shared cargo standard launch window. The launch window is based on the transfer orbit sun angle requirements of an established, common class of geosynchronous communications satellites. This standard window is applicable to mixed cargoes launched from the John F. Kennedy Space Center into 28.5 deg inclination orbits. The window consists of two time periods, each 2 hrs long and centered at 0023 and 1223 Greenwich mean time; it extends unchanged throughout the year.

Deatkine, David D.↗
NASA NTRS2003

Life-Prediction Parameters of Sapphire Determined for the Design of a Space Station Combustion Facility Window

To characterize the stress corrosion parameters and predict the life of a sapphire window being considered for use in the International Space Station's Fluids and Combustion Facility, researchers at the NASA Glenn Research Center conducted stress corrosion tests, fracture toughness tests, and reliability analyses, as shown in the figures. Standardized test methods, developed and updated by the author under the auspices of American Society for Testing and Materials, were employed. One interesting finding is that sapphire exhibits a susceptibility to stress corrosion in water similar to that of glass. In addition to generating the stress corrosion parameters and fracture toughness data, closed-form expressions for the variances of the crack growth parameters were derived. The expressions allow confidence bands to be easily placed on life predictions of ceramic components. Brittle materials such as sapphire and quartz are required for windows in a variety of applications such as the Fluids and Combustion Facility. To minimize the launch weight of such facilities, researchers must design the windows to be as lightweight as possible. The safe use of lightweight, brittle windows in structural applications is limited by two factors: low fracture toughness and slow crack growth, or stress corrosion. Stress corrosion of these and other optical materials can occur in relatively common environments, such as humid air. Access to the data has been requested by designers for use in the life prediction of a Northrop Grumman F16 instrument window and a Jet Propulsion Laboratory instrument window. One Space Act Agreement has been formed. Future work includes the measurement of the life of subscale windows.

Salem, Jonathan A.↗
NASA NTRS1988

Fabrication of MgF2 and LiF windows for the Hubble Space Telescope Imaging Spectrograph

Two prototype test windows (MgF2 and LiF) to be used on the 75-mm UV MAMA detector tubes for the Hubble Space Telescope Imaging Spectrograph are described. The spatial and optical constraints of this instrument dictate that the thickness of the window materials be no greater than 2-3 mm to achieve a minimum 50-percent transmission at hydrogen Lyman alpha (121.6 nm), and that the window must be domed to minimize optical aberrations and provide structural strength. The detector window has an input diameter of about 100 mm with a radius-of-curvature of 70 mm. The manufacturing processes involved in the fabrication of these windows is discussed, as well as test programs (optical and structural) to be performed at Goddard Space Flight Center.

Gormley, Daphne↗
NASA NTRS2015

50-Year Window to Establish a Space Faring Civilization

Humankind may only have a short window of 50 years to become a space-faring civilization, after which time the opportunity to do so may become too difficult or impractical to pursue. Current policies for space exploration and infrastructure development implicitly assume a gradualistic approach to technology, budgets, and mission execution -- the common thought has been that there will be plenty of time in humankind's future to become a space-based species, and whatever we are unable to accomplish will be borne by the generations that follow. However, considering natural events, available energy, and human tendencies, the timing to make the most effective effort to achieve multi-planet status might be now, before momentum is lost and we become distracted by Peak Oil and changing energy economies -- restarting a space program after such turmoil may be more difficult than would be practical without cheap, storable, high-energy density petroleum. "Space-faring civilization" is defined as an economically profitable space-based economy that demands the presence of humans off-world in order to sustain a high level of prosperity. An initial foothold for a space-based economy that would fit within the 50-year window might include Earth dependence on rare-earth elements or other hard-to-obtain minerals mined from moons or asteroids, or a permanent settlement on another planet. Using published sources, notional mass and energy requirements for a minimal self-sustaining Mars settlement is calculated, and the number of launch vehicles discussed. Setting the launch schedule to match that of current NASA projections, it could take more than 26 years of semi-annual launches to build up such a self-sustaining human settlement -- a cost and commitment that has not been acknowledged nor planned for. Considering the time required to establish a multi-planet species, this paper frames the required window of decision that, if not taken, could condemn the species to Earth subject to whatever natural or human-made calamities that endanger single-planet civilizations.

human exploration↗
NASA NTRS2013

Designing for Virtual Windows in a Deep Space Habitat

This paper discusses configurations and test analogs toward the design of a virtual window capability in a Deep Space Habitat. Long-duration space missions will require crews to remain in the confines of a spacecraft for extended periods of time, with possible harmful effects if a crewmember cannot cope with the small habitable volume. Virtual windows expand perceived volume using a minimal amount of image projection equipment and computing resources, and allow a limited immersion in remote environments. Uses for the virtual window include: live or augmented reality views of the external environment; flight deck, piloting, observation, or other participation in remote missions through live transmission of cameras mounted to remote vehicles; pre-recorded background views of nature areas, seasonal occurrences, or cultural events; and pre-recorded events such as birthdays, anniversaries, and other meaningful events prepared by ground support and families of the crewmembers.

habitation↗
NASA NTRS2022

Fracture Mechanics Properties of Fused Silicas Used for International Space Station Windowpanes

The fracture toughness and slow crack growth (SCG) parameters of a quartz-based silica and a high-purity fused silica were measured as part of a program to review the reliability of the International Space Station windows. The materials exhibit the same fracture toughness (.75 MPa m^(1/2) in N2) and very similar SCG parameters. The literature on fused silica indicates excellent agreement of fracture toughness, but a very wide range of SCG parameters, even from the same institution, with strength-based methods usually yielding a lower power law exponent than direct crack velocity measurements. Use of the exponential function is shown to provide better agreement between test methods, with velocity curves derived from strength tests of bare fiber and polished or ground test specimens paralleling those from wide-range, direct crack velocity observations, implying that constant stress rate tests can predict long lifetime via the exponential function. However, much variation still exists. SCG parameters for soda–lime silicate are much less sensitive to the test method than fused silica. Static load tests and stress intensity measurements resulted in a fatigue threshold of .3 MPa m^(1/2) for fused silica.

Silica, toughness, impact, crack growth, windows, ↗
NASA NTRS1987

Space station proximity operations windows: Human factors design guidelines

Proximity operations refers to all activities outside the Space Station which take place within a 1-km radius. Since there will be a large number of different operations involving manned and unmanned vehicles, single- and multiperson crews, automated and manually controlled flight, a wide variety of cargo, and construction/repair activities, accurate and continuous human monitoring of these operations from a specially designed control station on Space Station will be required. Total situational awareness will be required. This paper presents numerous human factors design guidelines and related background information for control windows which will support proximity operations. Separate sections deal with natural and artificial illumination geometry; all basic rendezvous vector approaches; window field-of-view requirements; window size; shape and placement criteria; window optical characteristics as they relate to human perception; maintenance and protection issues; and a comprehensive review of windows installed on U.S. and U.S.S.R. manned vehicles.

Haines, Richard F.↗
NASA NTRS1988

Space station proximity operations and window design

On-orbit proximity operations (PROX-OPS) consist of all extravehicular activity (EVA) within 1 km of the space station. Because of the potentially large variety of PROX-OPS, very careful planning for space station windows is called for and must consider a great many human factors. The following topics are discussed: (1) basic window design philosophy and assumptions; (2) the concept of the local horizontal - local vertical on-orbit; (3) window linear dimensions; (4) selected anthropomorphic considerations; (5) displays and controls relative to windows; and (6) full window assembly replacement.

Haines, Richard F.↗
NASA NTRSDate not supplied

Space Launch System Launch Windows and Day of Launch Processes

Lunar missions benefit from varying the launch azimuth as a function of launch time to allow longer launch windows with minimum performance impacts. This variable azimuth approach allows the vehicle to track the Moon’s apparent motion due to Earth’s rotation. The Space Launch System (SLS) Block 1 vehicle design requires the mission to launch into an elliptical parking orbit to provide sufficient energy to insert Orion into a Trans-Lunar Injection (TLI) orbit. The primary benefit of varying the launch azimuth, and as a result the achieved orbit inclination, allows the SLS Interim Cryogenic Propulsion Stage (ICPS) to perform its TLI burn closer to perigee and take advantage of performing a burn in a location where the burn will optimally raise apogee.

launch window↗