Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “60 - APPLIED LIFE SCIENCES”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1992

Project APEX: Advanced Phobos Exploration. Manned mission to the Martian moon Phobos

The manned exploration of Mars is a massive undertaking which requires careful consideration. A mission to the moon of Mars called Phobos as a prelude to manned landings on the Martian surface offers some advantages. One is that the energy requirements, in terms of delta 5, is only slightly higher than going to the Moon's surface. Another is that Phobos is a potential source of water and carbon which could be extracted and processed for life support and cryogenic propellants for use in future missions; thus, Phobos might serve as a base for extended Mars exploration or for exploration of the outer planets. The design of a vehicle for such a mission is the subject of our Aerospace System Design course this year. The materials and equipment needed for the processing plant would be delivered to Phobos in a prior unmanned mission. This study focuses on what it would take to send a crew to Phobos, set up the processing plant for extraction and storage of water and hydrocarbons, conduct scientific experiments, and return safely to Earth. The size, configuration, and subsystems of the vehicle are described in some detail. The spacecraft carries a crew of five and is launched from low Earth orbit in the year 2010. The outbound trajectory to Mars uses a gravitational assisted swing by of Venus and takes eight months to complete. The stay at Phobos is 60 days at which time the crew will be engaged in setting up the processing facility. The crew will then return to Earth orbit after a total mission duration of 656 days. Both stellar and solar observations will be conducted on both legs of the mission. The design of the spacecraft addresses human factors and life science; mission analysis and control; propulsion; power generation and distribution; thermal control; structural analysis; and planetary, solar, and stellar science. A 0.5 g artificial gravity is generated during transit by spinning about the lateral body axis. Nuclear thermal rockets using hydrogen as fuel are selected to reduce total launch mass and to shorten the duration of the mission. The nuclear systems also provide the primary electrical power via dual mode operation. The overall spacecraft length is 110 meters and the total mass departing from low Earth orbit is 900 metric tons.

Source record↗
NASA NTRS1996

Specimen Sample Preservation for Cell and Tissue Cultures

The era of the International Space Station with its longer duration missions will pose unique challenges to microgravity life sciences research. The Space Station Biological Research Project (SSBRP) is responsible for addressing these challenges and defining the science requirements necessary to conduct life science research on-board the International Space Station. Space Station will support a wide range of cell and tissue culture experiments for durations of 1 to 30 days. Space Shuttle flights to bring experimental samples back to Earth for analyses will only occur every 90 days. Therefore, samples may have to be retained for periods up to 60 days. This presents a new challenge in fresh specimen sample storage for cell biology. Fresh specimen samples are defined as samples that are preserved by means other than fixation and cryopreservation. The challenge of long-term storage of fresh specimen samples includes the need to suspend or inhibit proliferation and metabolism pending return to Earth-based laboratories. With this challenge being unique to space research, there have not been any ground based studies performed to address this issue. It was decided hy SSBRP that experiment support studies to address the following issues were needed: Fixative Solution Management; Media Storage Conditions; Fresh Specimen Sample Storage of Mammalian Cell/Tissue Cultures; Fresh Specimen Sample Storage of Plant Cell/Tissue Cultures; Fresh Specimen Sample Storage of Aquatic Cell/Tissue Cultures; and Fresh Specimen Sample Storage of Microbial Cell/Tissue Cultures. The objective of these studies was to derive a set of conditions and recommendations that can be used in a long duration microgravity environment such as Space Station that will permit extended storage of cell and tissue culture specimens in a state consistent with zero or minimal growth, while at the same time maintaining their stability and viability.

Meeker, Gabrielle↗
NASA NTRS2006

The ALTCRISS Project On Board the International Space Station

The Altcriss project aims to perform a long term survey of the radiation environment on board the International Space Station. Measurements are being performed with active and passive devices in different locations and orientations of the Russian segment of the station. The goal is perform a detailed evaluation of the differences in particle fluence and nuclear composition due to different shielding material and attitude of the station. The Sileye-3/Alteino detector is used to identify nuclei up to Iron in the energy range above approximately equal to 60 MeV/n; a number of passive dosimeters (TLDs, CR39) are also placed in the same location of Sileye-3 detector. Polyethylene shielding is periodically interposed in front of the detectors to evaluate the effectiveness of shielding on the nuclear component of the cosmic radiation. The project was submitted to ESA in reply to the AO the Life and Physical Science of 2004 and was begun in December 2005. Dosimeters and data cards are rotated every six months: up to now three launches of dosimeters and data cards have been performed and have been returned with the end expedition 12 and 13.

Cucinotta, Francis A.↗
NASA NTRS2011

NASA as a Convener: Government, Academic and Industry Collaborations Through the NASA Human Health and Performance Center

On October 18, 2010, the NASA Human Health and Performance center (NHHPC) was opened to enable collaboration among government, academic and industry members. Membership rapidly grew to 60 members (http://nhhpc.nasa.gov ) and members began identifying collaborative projects as detailed below. In addition, a first workshop in open collaboration and innovation was conducted on January 19, 2011 by the NHHPC resulting in additional challenges and projects for further development. This first workshop was a result of the SLSD successes in running open innovation challenges over the past two years. In 2008, the NASA Johnson Space Center, Space Life Sciences Directorate (SLSD) began pilot projects in open innovation (crowd sourcing) to determine if these new internet-based platforms could indeed find solutions to difficult technical problems. From 2008 to 2010, the SLSD issued 34 challenges, 14 externally and 20 internally. The 14 external challenges were conducted through three different vendors: InnoCentive, Yet2.com and TopCoder. The 20 internal challenges were conducted using the InnoCentive platform, customized to NASA use, and promoted as NASA@Work. The results from the 34 challenges involved not only technical solutions that were reported previously at the 61st IAC, but also the formation of new collaborative relationships. For example, the TopCoder pilot was expanded by the NASA Space Operations Mission Directorate to the NASA Tournament Lab in collaboration with Harvard Business School and TopCoder. Building on these initial successes, the NHHPC workshop in January of 2011, and ongoing NHHPC member discussions, several important collaborations are in development: Space Act Agreement between NASA and GE for collaborative projects, NASA and academia for a Visual Impairment / Intracranial Hypertension summit (February 2011), NASA and the DoD through the Defense Venture Catalyst Initiative (DeVenCI) for a technical needs workshop (June 2011), NASA and the San Diego Zoo in Biomimicry, NASA and the FAA Center of Excellence for Commercial Space Flight for collaborative projects, NASA and the FDA concerning automatic external defibrillators, and NASA and Tufts University for an education pilot. These and other collaborations will be detailed in the paper demonstrating that a government-sponsored convening entity (the NHHPC) can facilitate industry, academic, and non-profit collaborations for products of mutual benefit.

Davis, Jeffrey R.↗
NASA NTRS2002

Sensitivity of wheat and rice to low levels of atmospheric ethylene

Ethylene (C2H4) gas is produced throughout the life cycle of plants and can accumulate in closed growth chambers to levels 100 times higher than in outside environments. Elevated atmospheric C2H4 can cause a variety of abnormal responses, but the sensitivity to elevated C2H4 is not well characterized. We evaluated the C2H4 sensitivity of wheat (Triticum aestivum L.) and rice (Oryza sativa L.) in five studies. The first three studies compared the effects of continuous C2H4 levels ranging from 0 to 1000 nmol mol-1 (ppb) in a growth chamber throughout the life cycle of the plants. A short-term 1000 nmol mol-1 treatment was included in which exposure was stopped at anthesis. Yield was reduced by 36% in wheat and 63% in rice at 50 nmol mol-1 and both species were virtually sterile when continuously exposed to 1000 nmol mol-1. However, the yield reductions were much less with exposure that stopped at anthesis, suggesting the detrimental effect of C2H4 on yield was greatest around the time of seed set. Two additional studies evaluated the differential sensitivity of two wheat cultivars (Super Dwarf and USU-Apogee) to 50 nmol mol-1 C2H4 at three CO2 levels [350, 1200, 5000 micromoles mol-1 (ppm)] in a greenhouse. Yield of USU-Apogee was not significantly reduced by C2H4 but the yield of Super Dwarf was reduced by 60%. Elevated CO2 did not influence the sensitivity to C2H4. A difference in the C2H4 sensitivity of USU-Apogee between greenhouse and growth chamber trials suggests that C2H4 sensitivity is dependent on the environment. Collectively, the data suggest that relatively low levels of C2H4 could induce anomalous plant responses by accumulation in greenhouses and growth chambers with inadequate ventilation. The data also suggest that C2H4 sensitivity can be reduced by both genetic and environmental manipulations. 2002 Crop Science Society of America.

NASA Discipline Life Sciences Technologies↗
DOE OSTI2025

Simulation and measurement of the dynamic strain response in a prototypical spallation target

The Second Target Station (STS) at the Spallation Neutron Source (SNS) will address emerging scientific challenges by providing a source of intense cold neutrons to instruments optimized for this source. The STS target will use rotating tungsten blocks and will receive 1.3 GeV proton beam pulses from the SNS accelerator at a repetition rate of 15 Hz. The facility life is planned for 40 years, and each target assembly life is expected to be approximately 10 years. An accurate strain prediction is then critical for fatigue life assessment of STS target blocks because they will be subject to approximately 10 8 beam pulses per lifetime. As an R&D activity, the Los Alamos Neutron Science Center (LANSCE) Weapons Neutron Research (WNR) Target 2 (Blue Room) facility was used to test the strain response of prototypical target blocks to the thermal shock of a proton pulse. The blue room was well suited for a pulsed proton beam impact test of subscale STS target blocks; the 800 MeV proton energy is approximately 60 % of the 1.3 GeV proton energy expected from the SNS accelerator to the STS. The LANSCE Proton Storage Ring (PSR) and SNS are both short-pulse proton beam sources with nominal pulse widths of 250 ns and 661 ns, respectively, so the energy deposition in the target occurs in <1 μs pulse duration. Strain measurements on the outer surface of three target blocks (bare tungsten, tantalum-clad tungsten, niobium-clad tungsten) were recorded for comparison against neutronics and structural simulations. In conclusion, this experiment and the supporting simulations satisfied the following primary research goals for the STS target.

Dynamic strain response↗
NASA NTRS2011

COMPASS Final Report: Radioisotope Electric Propulsion (REP) Centaur Orbiter New Frontiers Mission

Radioisotope Electric Propulsion (REP) has been shown in past studies to enable missions to outer planetary bodies including the orbiting of Centaur asteroids. Key to the feasibility for REP missions are long life, low power electric propulsion (EP) devices, low mass Radioisotope Power System (RPS) and light spacecraft (S/C) components. In order to determine the key parameters for EP devices to perform these REP missions a design study was completed to design an REP S/C to orbit a Centaur in a New Frontiers (NF) cost cap. The design shows that an orbiter using several long lived (approx.200 kg xenon (Xe) throughput), low power (approx.700 W) Hall thrusters teamed with six (150 W each) Advanced Stirling Radioisotope Generators (ASRG) can deliver 60 kg of science instruments to a Centaur in 10 yr within the NF cost cap. Optimal specific impulses (Isp) for the Hall thrusters were found to be around 2000 s with thruster efficiencies over 40 percent. Not only can the REP S/C enable orbiting a Centaur (when compared to an all chemical mission only capable of flybys) but the additional power from the REP system can be used to enhance science and simplify communications. The mission design detailed in this report is a Radioisotope Power System (RPS) powered EP science orbiter to the Centaur Thereus with arrival 10 yr after launch, ending in a 1 yr science mapping mission. Along the trajectory, approximately 1.5 yr into the mission, the REP S/C does a flyby of the Trojan asteroid Tlepolemus. The total (Delta)V of the trajectory is 8.9 km/s. The REP S/C is delivered to orbit on an Atlas 551 class launch vehicle with a Star 48 B solid rocket stage

Oleson, Steven R.↗
NASA NTRS2009

Radioisotope Electric Propulsion Centaur Orbiter Spacecraft Design Overview

Radioisotope electric propulsion (REP) has been shown in past studies to enable missions to outerplanetary bodies including the orbiting of Centaur asteroids. Key to the feasibility for REP missions are long life, low power electric propulsion (EP) devices, low mass radioisotope power systems (RPS) and light spacecraft (S/C) components. In order to determine what are the key parameters for EP devices to perform these REP missions a design study was completed to design an REP S/C to orbit a Centaur in a New Frontiers cost cap. The design shows that an orbiter using several long lived (approximately 200 kg Xenon throughput), low power (approximately 700 W) Hall thrusters teamed with six (150 W each) Advanced Stirling Radioisotope Generators (ASRG) can deliver 60 kg of science instruments to a Centaur in 10 yr within the New Frontiers cost cap. Optimal specific impulses for the Hall thrusters were found to be around 2000 sec with thruster efficiencies over 40%. Not only can the REP S/C enable orbiting a Centaur (when compared to an all chemical mission only capable of flybys) but the additional power from the REP system can be reused to enhance science and simplify communications.

Oleson, Steve↗
NASA NTRS2018

Marshall Space Flight Center Research and Technology Report 2017

This report features over 60 technology development and scientific research efforts that collectively aim to enable new capabilities in spaceflight, expand the reach of human exploration, and reveal new knowledge about the universe in which we live. These efforts include a wide array of strategic developments: launch propulsion technologies that facilitate more reliable, routine, and cost effective access to space; in-space propulsion developments that provide new solutions to space transportation requirements; autonomous systems designed to increase our utilization of robotics to accomplish critical missions; life support technologies that target our ability to implement closed-loop environmental resource utilization; science instruments that enable terrestrial, solar, planetary and deep space observations and discovery; and manufacturing technologies that will change the way we fabricate everything from rocket engines to in situ generated fuel and consumables.

Research and Technology Report↗
NASA NTRS2002

NiH2 Reliability Impact Upon Hubble Space Telescope Battery Replacement

The NASA Hubble Space Telescope (HST) was designed to be deployed and later serviced for maintenance and upgrades, as required, by the space shuttle fleet, with a Goodyear mission life for the batteries. HST was deployed 380 miles above the Earth, from Space Shuttle Discovery, on April 25, 1990. Four servicing missions, (SM1, SM2, SM3A, AND SM3B) have been performed. Astronauts have replaced or modified optics, solar arrays, a power control unit, and various science packages. A fifth Servicing Mission, SM4 scheduled for early 2004, is planned to replace the batteries for the first time. The HST is powered by solar array wings and nickel hydrogen (NiH2) Duracell batteries, which are grouped into two parallel battery modules of three parallel batteries each. With a design life of 7 years at launch, these batteries have surpassed 12 years in orbit, which gives HST the highest number of charge/discharge cycles of any NiH2 battery currently in low earth orbit (LEO) application. Being in a LEO orbit, HST has a 45-minute umbra period, during which spacecraft power requirements normally force the batteries into discharge, and a 60-minute sun period, which is available for battery recharge. The intent of this paper is to address the issue of NiH2 battery reliability and how battery capacity degradation can impact scheduling of a Servicing Mission to bring replacement batteries to HST, and extend mission life till deployment of Next Generation Space Telescope (NGST), planned for 2008 at the earliest.

Rao, Gopalakrishna M.↗
NASA NTRS2001

Beagle 2: The Next Exobiology Mission to Mars

Beagle 2 is a 60 kg probe (with a 30 kg lander) developed in the United Kingdom for inclusion on the European Space Agency's 2003 Mars Express. Beagle 2 will deliver to the Martian surface a payload which consists of a high percentage of science instruments to landed spacecraft mass. Beagle 2 will be launched in June, 2003 with Mars Express on a Soyuz-Fregat rocket from the Baikonur Cosmodrome in Kazakhstan. Beagle 2 will land on Mars on December 26, 2003 in the Isidis Planitia basin (approximately 10 degrees N and 275 degrees W), a large sedimentary basin that overlies the boundary between ancient highlands and northern plains. Isidis Planitia, the third largest basin on Mars, which is possibly filled with sediment deposited at the bottom of long-standing lakes or seas, offers an ideal environment for preserving traces of life. Beagle 2 was developed to search for organic material and other volatiles on and below the surface of Mars in addition to the study of the inorganic chemistry and mineralogy. Beagle 2 will utilize a mechanical mole and grinder to obtain samples from below the surface, under rocks and inside rocks. A pair of stereo cameras will image the landing site along with a microscope for examination of surface and rock samples. Analyses will include both rock and soil samples at various wavelengths, X-ray spectrometer and Mossbauer spectrometer as well as a search for organics and other light element species (e.g. carbonates and water) and measurement of their isotopic compositions. Beagle 2 has as its focus the goal of establishing whether evidence for life existed in the past on Mars at the Isidis Planitia site or at least establishing if the conditions were ever suitable. Carbonates and organic components were first recognized as existing on Mars when they were found in the Martian meteorite Nakhla. Romanek et al showed the carbonates in ALH84001 were formed at low temperatures. McKay et al noted possible evidence of early life on Mars within the ALH84001 meteorite. Thomas-Keprta et al showed the magnetite biomarkers in ALH84001's carbonates are indistinguishable from those formed by magnetotactic bacteria found on Earth. Gibson et al showed there was significant evidence for liquid water and biogenic products present on Mars across a 3.9 billion year period. A mechanical arm (PAW) operates from the lander and is used for science operations along with sample acquisition. Instruments attached to the PAW include: stereo cameras, Mossbauer instrument, X-ray fluorescence instrument, microscope, environmental sensors, rock corer/grinder, a spoon, mirror, brushes, a mole attachment for acquisition of subsurface to depths of 1 to 2 meters and an illumination device. Each camera has 14 filters which have been optimized for mineralogy composition, dust and water vapor detection. The microscope's camera is designed for viewing the size and shape of dust particles, rock surfaces, microfossils, and characteristics of the samples prior to introduction into the gas analysis package (GAP). The camera has a resolution of 4 microns/pixel, features four color capability (red, green, blue and UV (ultraviolet) fluoresence), a depth of focus of 40 micrometers and translation stage of +3 millimeters. The heart of the Beagle 2's life detection package is the gas analysis package (GAP), which consists of a mass spectrometer with collectors at fixed masses for precise isotopic ratio measurements and voltage scanning for spectral analysis. Primary aim of the GAP is to search for the presence of bulk constituents, individual species, and isotopic fractionations for both extinct and extent life along with studying the low-temperature geochemistry of the hydrogen, carbon, nitrogen and oxygen components on Mars from both the surface and atmosphere. GAP is a magnetic sector mass spectrometer with the range of 1 to 140 amu which can be operated in both the static and dynamic modes. A triple Faraday collector array will be used for C, N and O ratios along with a double Faraday array for H/D. Pulse counting electron multiplier will be utilized for noble gases and selected organics. Anticipated detection limits are at the picomole level for operation in the static mode of operation and high precision isotopic measurements will be made in the dynamic mode. Sample processing and preparation system consists of reaction vessels along with references. Sample ovens capable of being heated are attached to the manifold for sample combustion. Surface, subsurface materials and interior rock specimens will be combusted in pure oxygen gas at various temperature intervals to release organic matter and volatiles. Combustion process will permit detection of all forms and all atoms of carbon present in the samples. A chemical processing system is capable of a variety of conversion reactions. Gases are manipulated either by cryogenic or chemical reactions and passed through the gas handling portion of the vacuum system. There are two modes of operation: quantitative analysis and precise isotopic measurements. Additional information is contained in the original extended abstract.

Gibson, Everett K., Jr.↗
NASA NTRSDate not supplied

The NASA Open Science Data Repository: Biomedical Data, Analysis Tools, and Informatic Collaborations

Increased biomedical risks and challenges associated with deep space missions require knowledge discovery, health countermeasures, and biomedical support capabilities. Maximally open-access and reusable data is needed by developers, scientists, and engineers to develop these systems. The NASA Open Science Data Repository (OSDR) is a maximally open access and FAIR database (ie., findable, accessible, interoperable, and reusable), and meets various scientific, technical, and operational needs. It offers users and submitters the ability to upload, download, search, share, analyze, cite, and visualize data across ‘omics, physiological, phenotypic, payload, hardware, behavioral, bioimaging, video, and environmental monitoring telemetry datasets. OSDR is an expanded database, based upon the successes of NASA GeneLab. OSDR has >460 studies with datasets covering model organisms to non-NASA human astronauts. There are ~12 datasets from the Inspiration 4 (I4) mission, spanning metagenomics, comprehensive metabolic panels, clonal hematopoiesis, spatial transcriptomics, proteomics, and cytokine panels. In the interest of data privacy, two I4 datasets with raw files relating to the epitranscriptome, and a new request feature is live in OSDR (with a backend review process established) developed from industry norms. OSDR is collecting and curating biomedical human data from a new sub-orbital research flight and is open to more space life science/biomedical submissions from the international and commercial sectors. OSDR also recently began a collaboration with the European Space Agency (ESA) to collect and curate >200 terabytes of human and model organism data. The OSDR submission portal is designed to ingest and curate ~25 ‘omics and ~50 physiological-phenotypic-imaging assay data types. Tools available for OSDR users include: 1) an Environmental Data Application to compare radiation, CO2, relative humidity, temperature, and other telemetry across missions and subjects, 2) the RadLab database, a collaboration between NASA, ESA, the German and Italian Space Agencies, and the Bulgarian Academy of Sciences, and 3) a Multi-study visualization tool which enables users to look across and combine ‘omics datasets. There are ~600 volunteer OSDR Analysis Working Group (AWG) members providing feedback on scientific data/metadata standards and collaborating to mine-reuse OSDR in research. OSDR/GeneLab has enabled ~60 publications reusing data as of October 2023.

space biology↗
NASA NTRS2000

Beagle 2 and NASA's Mars 2003 Orbiter: A Unique Exobiology Opportunity with an Orbiter

With the exploration strategy for Mars undergoing reexamination, the opportunity exists for the incorporation of the 60 kg Beagle 2 lander, developed in the United Kingdom for inclusion on ESA's 2003 Mars Express mission, with NASA's Mars 2003 orbiter derived from the Mars Global Orbiter. The combination of Beagle 2 with a Mars orbiter would result in a unique mission which could obtain information on Mars' life, climate and resources both from orbit as well as on the surface of the planet. Beagle 2 has been developed in the LJK for ESA as a low-cost opportunity to study the exobiology of Mars and the spacecraft is in its final stages of manufacture. Only limited modifications to the Beagle 2 package would be required for inclusion on NASA's Mars 2003 orbiter. With the ESA Mars Express mission launch in 2003 and a potential NASA Mars orbiter in 2003, both Beagle 2 landers on Mars would offer a low-cost, decreased risk and increased science return opportunity for the exploration of Mars at two distinct geologically interesting sites.

Gibson, Everett K., Jr.↗
NASA NTRSDate not supplied

A Brief Overview of Relevant Silicon Carbide Electronics and Sensor Development for Long Duration Venus Surface Exploration

This presentation concentrates on the potential of long duration Venus surface missions, and the role of Silicon Carbide (SiC) electronics and sensor advancements in such exploration. For example, SiC integrated circuit (IC) electronics have matured to a state where a simple long-life scientific probe is feasible for extended Venus surface operations. These electronics have been demonstrated for more than a year at 500˚C, and 60 days in high-fidelity simulated Venus surface conditions [1-2]. Further, high temperature chemical sensing technology, including SiC-based gas sensors, integrated with SiC electronics can enable future exploration of the Venus surface atmosphere [3]. Continued maturation of these high temperature electronics and sensors has been part of the Long-Lived In-Situ Solar System Explorer (LLISSE) project to provide an operational system for in situ exploration of the Venus surface up to 60 days [4]. A key focus of this work includes increasing the complexity and decreasing the power consumption of the ICs which will pave the way to enhanced capabilities, such as long-duration Venus seismic measurements and other mission capabilities currently under development. This is in parallel to work expanding the capabilities of the sensor technology to provide science measurements on the Venus surface. This presentation will give an overview of possible extended duration Venus surface exploration and some of the SiC-based technologies that can enable this exploration.

high temperature Venus surface electronics sensors↗
NASA NTRS2018

The Origins Space Telescope

The Universe has never been seen like this before. The window into the infrared opens only above Earth's atmosphere, and humanity has barely glimpsed outside. About half of the light emitted by stars, planets, and galaxies over the lifetime of the Universe emerges in the infrared. With an unparalleled sensitivity increase — up to a factor of 1,000 more than any previous or planned mission — the advance offered by the Origins Space Telescope (OST) is akin to that from the naked eye to humanity's first telescope, or from Galileo's first telescope to the first telescope in space. While key path-finding missions have glimpsed a rich infrared cosmos, extraordinary discovery space awaits; the time for a far-infrared revolution has begun.Are we alone or is life common in the Universe? OST will directly address this long-standing question by searching for signs of life in the atmospheres of potentially habitable terrestrial planets transiting M dwarf stars. How do planets become habitable? OST will trace the trail of cold water from the interstellar medium, through protoplanetary disks and into the outer reaches of our own Solar System. How do stars, galaxies, black holes and the elements of life form, from the cosmic dawn to today? With broad wavelength coverage and fast mapping speeds, OST will map millions of galaxies, simultaneously measuring star formation rates and black hole growth across cosmic time, peering deeper into the far reaches of the Universe than ever before.OST will be maintained at a temperature of 4 K, enabling its tremendous sensitivity gain, and will operate from 5 m to 600 m, encompassing the mid- and far-infrared. OST has two Mission Concepts: Concept 1 with a 9.1-m deployed off-axis primary, and Concept 2, described here, a non-deployed 5.9-m on-axis telescope with the equivalent collecting area of the James Webb Space Telescope (JWST). Concept 2 includes four instruments with capabilities for imaging (large surveys and pointed), spectroscopy (survey and high-resolution modes) and polarimetry, as well as an instrument for high-precision spectroscopy of transiting exoplanets. Concept 2 is optimized for maximum science return and minimal complexity, and offers fast mapping (approximately 60 arcseconds per second). We describe here the three key science themes for OST and the basic mission specifications.

Battersby, Cara↗
DOE OSTI2024

Latent Pitfalls in Microstructure-Based Modeling for Thermally Aged 9Cr-1Mo-V Steel (Grade 91)

A case study was conducted on a mechanistic model development that predicted tensile strength deterioration with thermal aging of 9Cr-1Mo-V steel in supporting the 60-year design life expected for advanced nuclear reactors. For property prediction beyond practical testing times, mechanistic modeling is highly desired, as it taps into the physics of structure–property relationships and therefore can generate reliable results for extrapolation. Meanwhile, as mechanistic models are often complicated, reflecting the intricacy of microstructure and strengthening mechanisms, pitfalls that are difficult to detect often exist. Here, this paper discusses latent pitfalls that are common in mechanistic modeling or specific in this 9Cr-1Mo-V case development through using the American Society of Mechanical Engineers verification and validation in computational solid mechanics (ASME V&V 10) standard for evaluating credibility of modeling in materials engineering. Suggestions are also made for enhancing reliability of microstructure-based modeling.

36 MATERIALS SCIENCE↗
NASA NTRSDate not supplied

Opposed-flow Spreading Flames: Effect of Sub-atmospheric Pressure on Spread and Burning Rates

Flame spread over solid fuels is a canonical problem in fire science, due to its direct implications on material flammability and importance in fire development. Flames in a microgravity environment can behave very differently than on Earth, posing additional risks for spaceflight life safety. Sub-atmospheric pressures in ground-based experiments have been proposed to approximately replicate the burning behavior of solid fuels in reduced gravity conditions because of similar effects on heat and mass transfer mechanisms from the flame to the solid. In opposed-flow flame spread, the solid fuel is heated by the flame ahead of its leading edge, and this process is strongly affected by the ambient conditions. In this work, we consider flames spreading over flat thin acrylic samples exposed to a forced flow of 20 cm/s, and pressures between 30 and 100 kPa. When radiation losses and chemical kinetic effects are neglected, experimental and theoretical results suggest an independence of the spread rate on pressure. However, the spread rate shows a decreasing trend with lower pressure in the range 30-60 kPa. The mass burning rate, calculated from the samples weight measured before and after the experiments, shows a similar trend. The flame length, on the other hand, shows a non-monotonic behavior, reaching a maximum at 60 kPa. Additionally, gas emissions measured during the experiments are used to estimate the heat release rate of the spreading flames. The comparison of the heat release rate obtained from the measured emissions and the estimated mass burning rates, suggests that chemical kinetics is not driving the decrease in flame spread observed at low pressures, whereas radiation losses could be responsible in analogy to what has been observed in micro and partial gravity studies. These results could provide more information to guide future Earth-based material flammability testing for spacecraft applications.

fire↗
NASA NTRS1994

TRMM-related research: Tropical rainfall and energy analysis experiment

The overall science objective of the participation in TRMM is the determination of daily rainfall and latent heating in the tropical atmosphere using TRMM and complementary spacecraft observations. The major focus these first three years has been to extend, in space and time, the TRMM satellite observations of rainfall. Observations from TRMM active and passive microwave radiometers will provide the fundamental observations for understanding the hydrological cycle of the tropics. Due to the orbit of the TRMM satellite and the extreme variability of convective rain systems, the TRMM observations provide rainfall estimates representative of a one month period. Monthly mean rainfall rates provide valuable information; however, this time scale limitation neglects the great value of the data towards a better understanding of the physics of tropical convection. Many tropical periodicities will not be characterized by these monthly averages, e.g. diurnal cycles, the 4-6 day easterly waves, and the 30 to 60 day cycle. In the spatial domain, due to its orbit, the TRMM satellite will over-fly many convective systems only once. Indeed, some precipitating systems will not be sampled at all. Observations from geostationary satellites can be used to extend the TRMM observations to smaller time and space scales. Although geostationary satellites cannot probe the interiors of precipitating systems, they do observe their life cycles. To acquire information on cloud water content and rain rate, it is proposed to combine geostationary and other satellite observations with the TRMM satellite measurements.

Suomi, Verner E.↗