SEARCH · Engineering Papers

Results for “SPACE”

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.

SourceResearch connectionFrom yearThrough year

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

At least 1,639 records · Page 91

All sources NASA NTRS DOE OSTI

NASA NTRS2017

Space Launch System Spacecraft and Payload Elements: Progress Toward Crewed Launch and Beyond

While significant and substantial progress continues to be accomplished toward readying the Space Launch System (SLS) rocket for its first test flight, work is already also underway on preparations for the second flight - using an upgraded version of the vehicle - and beyond. Designed to support human missions into deep space, Space Launch System (SLS), is the most powerful human-rated launch vehicle the United States has ever undertaken, and is one of three programs being managed by the National Aeronautics and Space Administration's (NASA's) Exploration Systems Development division. The Orion spacecraft program is developing a new crew vehicle that will support human missions beyond low Earth orbit (LEO), and the Ground Systems Development and Operations program is transforming Kennedy Space Center into a next-generation spaceport capable of supporting not only SLS but also multiple commercial users. Together, these systems will support human exploration missions into the proving ground of cislunar space and ultimately to Mars. For its first flight, SLS will deliver a near-term heavy-lift capability for the nation with its 70-metric-ton (t) Block 1 configuration. Each element of the vehicle now has flight hardware in production in support of the initial flight of the SLS, which will propel Orion around the moon and back. Encompassing hardware qualification, structural testing to validate hardware compliance and analytical modeling, progress in on track to meet the initial targeted launch date. In Utah and Mississippi, booster and engine testing are verifying upgrades made to proven shuttle hardware. At Michoud Assembly Facility in Louisiana, the world's largest spacecraft welding tool is producing tanks for the SLS core stage. Providing the Orion crew capsule/launch vehicle interface and in-space propulsion via a cryogenic upper stage, the Spacecraft/Payload Integration and Evolution (SPIE) element serves a key role in achieving SLS goals and objectives. The SPIE element marked a major milestone in 2014 with the first flight of original SLS hardware, the Orion Stage Adapter (OSA) which was used on Exploration Flight Test-1 with a design that will be used again on the first flight of SLS. The element has overseen production of the Interim Cryogenic Propulsion Stage (ICPS), an in-space stage derived from the Delta Cryogenic Second Stage, which was manufactured at United Launch Alliance in Decatur, Alabama, prior to being shipped to Florida for flight preparations. Manufacture of the Orion Stage Adapter and the Launch Vehicle Stage Adapter (LVSA) took place at the Friction Stir Facility located at Marshall Space Flight Center in Huntsville, Alabama. Marshall is also home to the Integrated Structural Test of the ICPS, LVSA, and OSA, subjecting the stacked components to simulated stresses of launch. The SPIE Element is also overseeing integration of 13 "CubeSat" secondary payloads that will fly on the first flight of SLS, providing access to deep space regions in a way currently not available to the science community. At the same time as this preparation work is taking place toward the first launch of SLS, however, the Space Launch System Program is actively working toward its second launch. For its second flight, SLS will be upgraded to the more-capable Block 1B configuration. While the Block 1 configuration is capable of delivering more than 70 metric tons to low Earth orbit, the Block 1B vehicle will increase that capability to 105 t. For that flight, the new configuration introduces two major new elements to the vehicle - an Exploration Upper Stage (EUS) that will be used for both ascent and in-space propulsion, and a Universal Stage Adapter (USA) that serves as a "payload bay" for the rocket, allowing the launch of large exploration systems along with the Orion spacecraft. Already, flight hardware is being prepared for the Block 1B vehicle. Welding is taking place on the second rocket's core stage. Flight hardware production has begun on booster components. An RS-25 engine slated for that flight has been tested. Development work is taking place on the Exploration Upper Stage, with contracts in place for both the stage and the RL10 engines which will power it. (The EUS will use four RL10 engines, an increase from one on the ICPS.) For the crew configuration of the Block 1B vehicle, the SLS SPIE element is managing the USA and accompanying Payload Adapter, which will accommodate both large payloads co-manifested with Orion and small-satellite secondary payloads. This co-manifested payload capacity will be instrumental for missions into the Proving Ground around the moon, where NASA will test new systems and demonstrate new capabilities needed for human exploration farther into deep space.

Schorr, Andrew A.↗

NASA NTRSDate not supplied

CubeSat Payloads on NASA’s Space Launch System Pave the Way for Artemis Moon Missions

Preparing for first launch in 2021, NASA’s Space Launch System (SLS) super heavy-lift launch vehicle will usher in a new era of human spaceflight, returning astronauts to the Moon as part of the Artemis program. Although designed to send crew in the Orion spacecraft and large payloads to the Moon and beyond, SLS also provides CubeSats with rideshare opportunities for missions to deep space. The first launch of SLS and Orion, Artemis I, has 13 6U CubeSats manifested. The payloads have been tested and will soon ship to Kennedy Space Center (KSC) to be integrated into commercial off-the-shelf (COTS) dispensers and integrated into the SLS Block 1 vehicle. Leveraging launches for the Artemis program to deploy rideshare smallsats to deep space provides a low-cost opportunity to perform missions that previously would have required a larger spacecraft and a dedicated launch, and offers additional benefits to both NASA and the smallsat community. CubeSats, including those manifested on the Artemis I flight, have a valuable role to play in the Artemis program, providing data to address NASA’s identified Strategic Knowledge Gaps (SKGs) in its plans to permanently establish humanity in deep space. Payload sponsors and developers for the Artemis I CubeSats hail from a variety of NASA industry partners and mission directorates, as well as international space agencies and universities. Several payloads destined for cislunar space will demonstrate propulsion systems and other technologies useful to future exploration. Science missions manifested on the Artemis I flight include characterizing the effects of deep space radiation on living organisms, searching for hydrogen and other volatiles on the Moon’s South Pole, and studying the lunar radiation environment. Three of the payloads were selected through NASA’s Centennial Challenges Program. Those payloads are competing for prize money while meeting specific technical development goals, such as communication with Earth from millions of miles in space. Student involvement in almost half of the Artemis I payload development allows STEM engagement with SLS and NASA’s Artemis program. As the initial vehicle to fly, the SLS Block 1 vehicle will lay the foundation for a generation of human and robotic deep space exploration missions. The Block 1 core stage is undergoing final testing at Stennis Space Center in 2020 before transportation to KSC for integration and launch in 2021. Following the Block 1 vehicle, the Block 1B and Block 2 vehicles will incorporate propulsion system upgrades and other changes to increase lift capability. In addition to sending the Orion vehicle to TLI, SLS can also be outfitted with large-diameter fairings to send robotic probes to deep space. With unparalleled lift, volume and departure energy, SLS is poised to usher in a new generation of spaceflight. In addition to launching Orion and large-volume missions, CubeSats may also be a part of Artemis missions to deep space.

Kimberly Robinson↗

NASA NTRS2022

Space Weather: From Solar Origins to Risks and Hazards Evolving in Time

Space Weather is the portion of space physics that has a direct effect onhumankind. Space Weather is an old branch of space physics that originatesback to 1808 with the publication of a paper by the great naturalist Alexandervon Humboldt (Von Humboldt, Ann. Phys. 1808, 29, 425–429),first defining a“Magnetische Ungewitter”or magnetic storm from auroral observations fromhis home in Berlin, Germany. Space Weather is currently experiencing explosivegrowth, because its effects on human technologies have become more andmore diverse. Space Weather is due to the variability of solar processes thatcause interplanetary, magnetospheric, ionospheric, atmospheric and groundlevel effects. Space Weather can at times have strong impacts on technologicalsystems and human health. The threats and risks are not hypothetical, and in theevent of extreme Space Weather events the consequences could be quitesevere for humankind. The purpose of the review is to give a brief overall view ofthe full chain of physical processes responsible for Space Weather risks andhazards, tracing them from solar origins to effects and impacts in interplanetaryspace, in the Earth’s magnetosphere and ionosphere and at the ground. Inaddition, the paper shows that the risks associated with Space Weather have notbeen constant over time; they have evolved as our society becomes more andmore technologically advanced. The paper begins with a brief introduction tothe Carrington event, arguably the greatest geomagnetic storm in recordedhistory. Next, the descriptions of the strongest known Space Weather processesare reviewed, tracing them from their solar origins. The concepts ofgeomagnetic storms and substorms are briefly introduced. The main effects/impacts of Space Weather are also considered, including geomagneticallyinduced currents (GICs) which are thought to cause power outages. Theeffects of radiation on avionics and human health, ionospheric effects andimpacts, and thermosphere effects and satellite drag will also be discussed.Finally, we will discuss the current challenges of Space Weather forecasting andexamine some of the worst-case scenarios.

Natalia Buzulukova↗

NASA NTRSDate not supplied

Space Crop Production Gaps and Challenges

As astronauts venture farther from Earth, and stay for longer periods, the space food system will increase in importance. Crop production can supplement a pre-packaged space diet to provide nutrition and dietary variety for space crews. In future missions, bioregenerative approaches may be used to generate a larger percentage of the diet, as well as help to reduce life support system burdens and resupply from Earth. Plants may also provide behavioral health benefits to crew members living in the isolated, confined environment of a space habitat. A number of unique challenges exist for growth of plants in microgravity and on other reduced gravity surfaces like the moon and Mars. Testing plant growth inside the Veggie and Advanced Plant Habitat (APH) chambers on the International Space Station is allowing us to understand the impacts of gravity and spaceflight on crop growth, nutritional content, acceptability, and the importance of plants to astronauts living and working away from Earth. We are also gaining a better understanding of food safety concerns and the behavior of space plant microbiomes and plant pathogens, but major gaps in knowledge remain. As we move from research towards operational space crop production to enable exploration, there are numerous gaps in technology, knowledge, and practice related to space crop growth that must be addressed. Research and development in key focus areas such as effective water and nutrient delivery at variable gravity levels, autonomous plant health monitoring, growth system cleaning and disinfection, and selection of ideal space crops are needed to fill these gaps. Breeding or engineering custom space crops may impact areas including plant growth and development, plant physiology, produce nutrition, organoleptic acceptability, and post-harvest characteristics, and these may further enable space crop production scenarios. Space crop challenges are multifaceted and require diverse interdisciplinary teams working together to develop effective solutions. Solving these requires an array of skill sets from across the biological and physical sciences, engineering, and human social sciences. Solutions to help ensure food security off-Earth may also translate to more sustainable terrestrial crop production approaches, and regular dialog between industry, academia, and government organizations working in related fields benefit all. Additional help can come from engagement with student researchers at various levels through courses, participatory science projects, and open science activities which can provide useful data. Global coordination and integration between space agencies and partners will be essential.

Gioia Donna Massa↗

NASA NTRSDate not supplied

Space Crop Production Gaps and Challenges

Gioia Massa↗

NASA NTRS2013

Earth Observation from Space - The Issue of Environmental Sustainability

Remote sensing scientists work under assumptions that should not be taken for granted and should, therefore, be challenged. These assumptions include the following: 1. Space, especially Low Earth Orbit (LEO), will always be available to governmental and commercial space entities that launch Earth remote sensing missions. 2. Space launches are benign with respect to environmental impacts. 3. Minimization of Type 1 error, which provides increased confidence in the experimental outcome, is the best way to assess the significance of environmental change. 4. Large-area remote sensing investigations, i.e. national, continental, global studies, are best done from space. 5. National space missions should trump international, cooperative space missions to ensure national control and distribution of the data products. At best, all of these points are arguable, and in some cases, they're wrong. Development of observational space systems that are compatible with sustainability principles should be a primary concern when Earth remote sensing space systems are envisioned, designed, and launched. The discussion is based on the hypothesis that reducing the environmental impacts of thedata acquisition step,which is at the very beginning of the information streamleading to decision and action, will enhance coherence in the information streamand strengthen the capacity of measurement processes to meet their stated functional goal, i.e. sustainable management of Earth resources. We suggest that unconventional points of view should be adopted and when appropriate, remedial measures considered that could help to reduce the environmental footprint of space remote sensing and of Earth observation and monitoring systems in general. This article discusses these five assumptions inthe contextof sustainablemanagementof Earth's resources. Takingeachassumptioninturn,we find the following: (1) Space debris may limit access to Low Earth Orbit over the next decades. (2) Relatively speaking, given that they're rare event, space launches may be benign, but study is merited on upper stratospheric and exospheric layers given the chemical activity associated with rocket combustion by-products. (3) Minimization of Type II error should be considered in situations where minimization of Type I error greatly hampers or precludes our ability to correct the environmental condition being studied. (4) In certain situations, airborne collects may be less expensive and more environmentally benign, and comparative studies should be done to determine which path is wisest. (5) International cooperation and data sharing will reduce instrument and launch costs and mission redundancy. Given fiscal concerns of most of the major space agencies e e.g. NASA, ESA, CNES e it seems prudent to combine resources.

Earth observation systems↗

NASA NTRSDate not supplied

Maturation of In-space Welding in Reduced Gravity and Reduced Pressure Environments Through Progression to Suborbital Flight Experiments

Development of in-space welding (ISW) is a key and enabling manufacturing technology as welding is currently involved in producing approximately 90% of durable goods, and this trend is expected to hold for in-space manufacturing as well. ISW is critical to a sustainable space economy. To mature in-space welding, numerous gaps must be closed since NASA has not made a weld in space in 50 years. Advancing laser beam welding (LBW) towards a suborbital flight demonstration will help mature the process for in-space assembly & manufacturing (ISAM) through demonstration in relevant environments and achieving technology readiness milestones. LBW technologies and science improved by this work will benefit in-space manufacturing, long-term sustainability of space structures & operations, and the overall space economy. Ground-based welding of aerospace hardware requires an Edisonian approach to qualify a welding process; however, this approach is infeasible for ISW qualification due to mass, volume, logistic, and cost challenges inherent to the space environment. To address this challenge, we are conducting ground and suborbital tests with partners performing parabolic flights to gather data on LBW processes and infuse them into NASA & partner missions. This progression from ground to flight experiments will elucidate relevant physics during LBW: 1) reduced gravity, 2) reduced pressure, and 3) extreme temperature. Data from post-flight evaluation and in situ instrumentation will feed integrated computational materials engineering (ICME) tools to reduce the burden of ISW infusion by establishing a link between space and terrestrial environments, ultimately accelerating the qualification of LBW in space.

in-space welding↗

NASA NTRS2024

Metabolic Suppression: A Promising Solution to Unlock the Future of Space Travel

Space tourism is no longer a distant dream but a present-day reality, with current excursions consisting of suborbital jaunts, and near future excursions to including lunar expeditions and, eventually, trips to Mars. Beneath the allure of weightlessness and cosmic views, however, lies a set of serious health risks for space travelers, including muscle and bone issues, heart problems, and cognitive impairment. In this mini review, we delve into the topic of metabolic suppression, an innovative approach to mitigating the deleterious effects of space travel that has been proposed for astronauts that may be appropriate for space tourists as well. Drawing inspiration from the survival strategies observed in hibernating animals and often depicted in sci-fi narratives where crews are in “suspended animation” throughout most of the voyage, this method involves inducing a reversible state of dormancy, akin to torpor, in human space travelers. The objective of metabolic suppression is to safeguard space travelers from the adverse impacts of extended exposure to microgravity and space radiation on long duration expeditions, so that on arrival at their destination, they can be healthy and ready to go. We shed light on ongoing research endeavors led by the National Aeronautics and Space Administration (NASA), the European Space Agency (ESA), and other prominent organizations dedicated to investing in and advancing metabolic suppression technologies for professional space travel, that may also enable space tourism to ever more distant destinations

Space Tourism↗

DOE OSTI2022

The Quantum Condition Space

Abstract The fundamental properties of quantum physics are exploited to evaluate event probabilities with projection measurements. Next, to study what events can be specified by quantum methods, the concept of the condition space is introduced, which is found to be the dual space of the classical outcome space of bit strings. Like the classical outcome space generates the quantum state space, the condition space generates the quantum condition space being the central idea of this work. The quantum condition space permits the existence of entangled conditions having no classical equivalent. In addition, the quantum condition space is related to the quantum state space by a Fourier transform guaranteed by the Pontryagin duality, and therefore an entropic uncertainty principle can be defined. The quantum condition space offers a novel perspective of understanding quantum states with the duality picture. Furthermore, the quantum conditions have physical meanings and realizations of their own and thus may be studied for purposes beyond the original motivation of characterizing events for probability evaluation. Finally, the relation between the condition space and quantum circuits provides insights into how quantum states are collectively modified by quantum gates, which may lead to deeper understanding of the complexity of quantum circuits.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

NASA NTRS1976

Space power demonstration stations

NASA major planning decisions from 1955 to date are summarized and new concepts connected with the advent of the Space Transportation Systems (STS) are set forth. The future Shuttle utilizations are considered, from 'manned booster' function for space transportation to such operations as deployment of modules and stations and assembly of large structures in space. The permanent occupancy of space will be a major goal of the space systems development in the 1980's with the following main phases: (1) achievement of easy access to earth orbit by means of the Shuttle and Spacelab; (2) achievement of permanent occupancy (Space Stations); (3) self-sufficiency of man in space. New techniques of space operation will become possible, using much larger, complicated satellites and simplified ground stations. Orbital assembly of large stations, using a permanent base in orbit, will enable practical utilization of space systems for everyday needs. Particular attention is given to the space solar power concept, involving the location in space of large satellite systems. Results of the studies on Manned Orbital Systems Concept (MOSC) and some future possibilities of Space Stations are analyzed.

Freitag, R. F.↗

NASA NTRS1982

Deep space communication - A one billion mile noisy channel

Deep space exploration is concerned with the study of natural phenomena in the solar system with the aid of measurements made at spacecraft on deep space missions. Deep space communication refers to communication between earth and spacecraft in deep space. The Deep Space Network is an earth-based facility employed for deep space communication. It includes a network of large tracking antennas located at various positions around the earth. The goals and achievements of deep space exploration over the past 20 years are discussed along with the broad functional requirements of deep space missions. Attention is given to the differences in space loss between communication satellites and deep space vehicles, effects of the long round-trip light time on spacecraft autonomy, requirements for the use of massive nuclear power plants on spacecraft at large distances from the sun, and the kinds of scientific return provided by a deep space mission. Problems concerning a deep space link of one billion miles are also explored.

Smith, J. G.↗

NASA NTRS1988

Space station as a vital focus for advancing the technologies of automation and robotics

A major guideline for the design of the U.S. Space Station is that the Space Station address a wide variety of functions. These functions include the servicing of unmanned assets in space, the support of commercial labs in space and the efficient management of the Space Station itself; the largest space asset. The technologies of Automation and Robotics have the promise to help in reducing Space Station operating costs and to achieve a highly efficient use of the human in space. The use of advanced automation and artificial intelligence techniques, such as expert systems, in Space Station subsystems for activity planning and failure mode management will enable us to reduce dependency on a mission control center and could ultimately result in breaking the umbilical link from Earth to the Space Station. The application of robotic technologies with advanced perception capability and hierarchical intelligent control to servicing system will enable the servicing of assets either in space or in situ with a high degree of human efficiency. The results of studies leading toward the formulation of an automation and robotics plan for Space Station development are presented.

Varsi, Giulio↗

NASA NTRS1990

The challenge of assembling a space station in orbit

Assembly of a space station in orbit is a challenging and complicated task. If mankind is to exploit the knowledge already gained from space flight and continue to advance the frontiers of space exploration, then space stations in orbit must be part of the overall space infrastructure. Space stations, like the Freedom, having relatively large mass which greatly exceeds the lifting capability of their transportation system, are candidates for on-orbit assembly. However, when a large wide-body booster is available, there are significant advantages to having a deployable space station assembled on Earth and transported into orbit intact or in a few large pieces. The United States will build the Space Station Freedom by the assembly method. Freedom's assembly is feasible, but a significant challenge, and it will absorb much of NASA's effort in the next 8 years. The Space Station Freedom is an international program which will be the centerpiece of the free world's space activities in the late 1990's. Scientific information and products from the Space Station Freedom and its use as a transportation depot will advance technology and facilitate the anticipated manned space exploration surge to the Moon and Mars early in the 21st century.

Brand, Vance D.↗

NASA NTRS1992

Space technology research plans

Development of new technologies is the primary purpose of the Office of Aeronautics and Space Technology (OAST). OAST's mission includes the following two goals: (1) to conduct research to provide fundamental understanding, develop advanced technology and promote technology transfer to assure U.S. preeminence in aeronautics and to enhance and/or enable future civil space missions: and (2) to provide unique facilities and technical expertise to support national aerospace needs. OAST includes both NASA Headquarters operations as well as programmatic and institutional management of the Ames Research Center, the Langley Research Center and the Lewis Research Center. In addition. a considerable portion of OAST's Space R&T Program is conducted through the flight and science program field centers of NASA. Within OAST, the Space Technology Directorate is responsible for the planning and implementation of the NASA Space Research and Technology Program. The Space Technology Directorate's mission is 'to assure that OAST shall provide technology for future civil space missions and provide a base of research and technology capabilities to serve all national space goals.' Accomplishing this mission entails the following objectives: y Identify, develop, validate and transfer technology to: (1) increase mission safety and reliability; (2) reduce flight program development and operations costs; (3) enhance mission performance; and (4) enable new missions. Provide the capability to: (1) advance technology in critical disciplines; and (2) respond to unanticipated mission needs. In-space experiments are an integral part of OAST's program and provides for experimental studies, development and support for in-space flight research and validation of advanced space technologies. Conducting technology experiments in space is a valuable and cost effective way to introduce advanced technologies into flight programs. These flight experiments support both the R&T base and the focussed programs within OAST.

Hook, W. Ray↗

NASA NTRS1992

Fusion energy for space: Feasibility demonstration. A proposal to NASA

This proposed program is to initiate a space flight research and development program to develop fusion energy for the space applications of direct space propulsion and direct space power, that is, a Space Fusion Energy (SFE) program. 'Direct propulsion' refers to the use of plasma energy directly for thrust without requiring other energy conversion systems. Further, to provide space missions with large electrical power, 'direct space power' is proposed whereby the direct conversion of charged particles into electricity is used, thereby avoiding thermal conversion system losses. The energy release from nuclear fusion reactions makes these highly efficient, high power space systems possible. The program as presented conducts in an orderly, hierarchical manner the necessary planning, analyses, and testing to demonstrate the practical use of fusion energy for space. There is nothing discussed that is known to be theoretically impossible. Validation of the engineering principles is sought in this program which uses a cost-benefit approach. Upon successful program completion, space will become more accessible and space missions more safely conducted. The country will have taken a giant step toward the commercialization of space. The mission enabling capability provided by fusion energy is well beyond mission planners' current dreams.

Schulze, Norman R.↗

NASA NTRS1989

Application of statistical distribution theory to launch-on-time for space construction logistic support

The ability to launch-on-time and to send payloads into space has progressed dramatically since the days of the earliest missile and space programs. Causes for delay during launch, i.e., unplanned 'holds', are attributable to several sources: weather, range activities, vehicle conditions, human performance, etc. Recent developments in space program, particularly the need for highly reliable logistic support of space construction and the subsequent planned operation of space stations, large unmanned space structures, lunar and Mars bases, and the necessity of providing 'guaranteed' commercial launches have placed increased emphasis on understanding and mastering every aspect of launch vehicle operations. The Center of Space Construction has acquired historical launch vehicle data and is applying these data to the analysis of space launch vehicle logistic support of space construction. This analysis will include development of a better understanding of launch-on-time capability and simulation of required support systems for vehicle assembly and launch which are necessary to support national space program construction schedules. In this paper, the author presents actual launch data on unscheduled 'hold' distributions of various launch vehicles. The data have been supplied by industrial associate companies of the Center for Space Construction. The paper seeks to determine suitable probability models which describe these historical data and that can be used for several purposes such as: inputs to broader simulations of launch vehicle logistic space construction support processes and the determination of which launch operations sources cause the majority of the unscheduled 'holds', and hence to suggest changes which might improve launch-on-time. In particular, the paper investigates the ability of a compound distribution probability model to fit actual data, versus alternative models, and recommends the most productive avenues for future statistical work.

Morgenthaler, George W.↗

NASA NTRS1993

Assured Mission Support Space Architecture (AMSSA) study

The assured mission support space architecture (AMSSA) study was conducted with the overall goal of developing a long-term requirements-driven integrated space architecture to provide responsive and sustained space support to the combatant commands. Although derivation of an architecture was the focus of the study, there are three significant products from the effort. The first is a philosophy that defines the necessary attributes for the development and operation of space systems to ensure an integrated, interoperable architecture that, by design, provides a high degree of combat utility. The second is the architecture itself; based on an interoperable system-of-systems strategy, it reflects a long-range goal for space that will evolve as user requirements adapt to a changing world environment. The third product is the framework of a process that, when fully developed, will provide essential information to key decision makers for space systems acquisition in order to achieve the AMSSA goal. It is a categorical imperative that military space planners develop space systems that will act as true force multipliers. AMSSA provides the philosophy, process, and architecture that, when integrated with the DOD requirements and acquisition procedures, can yield an assured mission support capability from space to the combatant commanders. An important feature of the AMSSA initiative is the participation by every organization that has a role or interest in space systems development and operation. With continued community involvement, the concept of the AMSSA will become a reality. In summary, AMSSA offers a better way to think about space (philosophy) that can lead to the effective utilization of limited resources (process) with an infrastructure designed to meet the future space needs (architecture) of our combat forces.

Hamon, Rob↗

NASA NTRS1997

Assessment and Management of the Risks of Debris Hits During Space Station EVAs

The risk of EVAs is critical to the decision of whether or not to automate a large part of the construction of the International Space Station (ISS). Furthermore, the choice of the technologies of the space suit and the life support system will determine (1) the immediate safety of these operations, and (2) the long-run costs and risks of human presence in space, not only in lower orbit (as is the case of the ISS) but also perhaps, outside these orbits, or on the surface of other planets. The problem is therefore both an immediate one and a long-term one. The fundamental question is how and when to shift from the existing EMU system (suit, helmet, gloves and life support system) to another type (e.g. a hard suit), given the potential trade-offs among life-cycle costs, risks to the astronauts, performance of tasks, and uncertainties about new systems' safety inherent to such a shift in technology. A more immediate issue is how to manage the risks of EVAs during the construction and operation of the ISS in order to make the astronauts (in the words of the NASA Administrator) "as safe outside as inside". For the moment (June 1997), the plan is to construct the Space Station using the low-pressure space suits that have been developed for the space shuttle. In the following, we will refer to this suit assembly as EMU (External Maneuvering Unit). It is the product of a long evolution, starting from the U.S. Air Force pilot suits through the various versions and changes that occurred for the purpose of NASA space exploration, in particular during the Gemini and the Apollo programs. The Shuttle EMU is composed of both soft fabrics and hard plates. As an alternative to the shuttle suit, at least two hard suits were developed by NASA: the AX5 and the MRKIII. The problem of producing hard suits for space exploration is very similar to that of producing deep-sea diving suits. There was thus an opportunity to develop a suit that could be manufactured for both purposes with the economies of scale that could be gained from a two-branch manufacturing line (space and deep sea). Of course, the space suit would need to be space qualified. Some of the problems in adopting one of the hard suits were first that the testing had to be completed, and second that it required additional storage space. The decision was made not to develop a hard suit in time for the construction and operation of the ISS. Instead, to improve the safety of the current suit, it was decided to reinforce the soft parts of the shuttle EMU with KEVLAR linings to strengthen it against debris impacts. Test results, however, show that this advanced suit design has little effect on the penetration characteristics.

Pate-Cornell, Elisabeth↗