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At least 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
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 NTRS2023

Information and Best Practices Related to NASA Nuclear Flight Safety for Space Flights Involving Space Nuclear Systems

The purpose of this handbook is to facilitate a repeatable and robust process that promotes clear and effective interfaces between activities and stakeholders focused on meeting nuclear flight safety requirements for missions utilizing space nuclear systems (SNS), within the context of NASA’s broader nuclear-related activities and interfaces. NPR 8715.26, Nuclear Flight Safety, requires that the NASA project manager “incorporate nuclear flight safety considerations starting with program or project formulation through the point at which the SNS or other radioactive material no longer has the potential to affect Earth’s biosphere.” NASA’s use of SNS inherently involves partnering with other stakeholders to conduct a range of related activities that interface with nuclear flight safety. From a categorical perspective these include: (i) meeting the authorities and licensing requirements for possession and use of nuclear material, as governed by other Federal authorities; (ii) conducting National Environmental Policy Act (NEPA) activities for nuclear-enabled missions; (iii) meeting Federal nuclear launch authorization requirements; (iv) conducting radiological contingency planning activities, including those associated with international commitments; (v) performing risk communication and public outreach activities; and (vi) ensuring decommissioning and disposal strategies reflect National policies and interests. It is the intent of this handbook to promote an effective interface between nuclear flight safety and these interrelated categorical activities. In addition to activities undertaken with partnering agencies, there are individual nuclear-related activities and programs that have a nexus to nuclear flight safety, and these include: (i) applicable NASA Standing Review Boards; (ii) the US Department of Energy nuclear safety activities conducted in partnership with NASA under Memoranda of Understanding; (iii) the Department of Defense’s Range Safety activities; (iv) NASA’s general involvement in interagency and international dialogues regarding nuclear safety; (v) the NASA-administered Interagency Nuclear Safety Review Board; (vi) NASA’s program and project governance activities and nuclear-specific Technical Discipline Team activities under the Office of the Chief Engineer; and others. It is the intent of this handbook to promote effective leveraging of these additional interrelated organizational activities, as appropriate.

Donald Helton↗
NASA NTRS1991

CENDI - A strategic interagency alliance in the 1990s

The goals, functions, and accomplishments of the CENDI Group, a government interagency cooperative organization formed to improve federal research and development productivity and R&D information management systems through information exchange, are briefly reviewed. The five member agencies are the Departments of Commerce, Energy, Defense, and Health and Human Services, and NASA. CENDI provides a means for its members to share technologies, resources, ideas, information, management activities, and standards. The top priorities of CENDI are: work with R&D managers to improve productivity; provide technical data and information to all users; improve the effectiveness and efficiency of all CENDI agency operations; and familiarize R&D managers and policy makers with the value of STI.

Caponio, Joseph↗
NASA NTRS1994

Mishap risk control for advanced aerospace/composite materials

Although advanced aerospace materials and advanced composites provide outstanding performance, they also present several unique post-mishap environmental, safety, and health concerns. The purpose of this paper is to provide information on some of the unique hazards and concerns associated with these materials when damaged by fire, explosion, or high-energy impact. Additionally, recommended procedures and precautions are addressed as they pertain to all phases of a composite aircraft mishap response, including fire-fighting, investigation, recovery, clean-up, and guidelines are general in nature and not application-specific. The goal of this project is to provide factual and realistic information which can be used to develop consistent and effective procedures and policies to minimize the potential environmental, safety, and health impacts of a composite aircraft mishap response effort.

Olson, John M.↗
NASA NTRS2011

Risk Management of Jettisoned Objects in LEO

The construction and maintenance of the International Space Station (ISS) has led to the release of many objects into its orbital plane, usually during the course of an extra-vehicular activity (EVA). Such releases are often unintentional, but in a growing number of cases, the jettison has been intentional, conducted after a careful assessment of the net risk to the partnership and to other objects in space. Since its launch in 1998 the ISS has contributed on average at least one additional debris object that is simultaneously in orbit with the station, although the number varies widely from zero to eight at any one moment. All of these objects present potential risks to other objects in orbit. Whether it comes from known and tracked orbiting objects or from unknown or untrackable objects, collision with orbital debris can have disastrous consequences. Objects greater than 10cm are generally well documented and tracked, allowing orbiting spacecraft or satellites opportunities to perform evasive maneuvers (commonly known as Debris Avoidance Maneuvers, or DAMs) in the event that imminent collision is predicted. The issue with smaller debris; however, is that it is too numerous to be tracked effectively and yet still poses disastrous consequences if it intercepts a larger object. Due to the immense kinetic energy of any item in orbit, collision with debris as small as 1cm can have catastrophic consequences for many orbiting satellites or spacecraft. Faced with the growing orbital debris threat and the potentially catastrophic consequences of a collision-generated debris shower originating in an orbit crossing the ISS altitude band, in 2007 the ISS program manger asked program specialists to coordinate a multilateral jettison policy amongst the ISS partners. This policy would define the acceptable risk trade rationale for intentional release of a debris object, and other mandatory constraints on such jettisons to minimize the residual risks whenever a jettison was accepted. Although ISS-related debris often presents untenable risks to the EVA crew, IVA crew, or to a departing cargo vehicle for a controlled disposal, such released objects also present a ballistic nuisance to the visiting vehicle traffic, and a potential fragmentation threat to the hundreds of other functional and debris objects whose perigees lie below the ISS orbital altitude. Thus, every such jettison decision is a conscious risk trade.

Bacon, John B.↗
NASA NTRS2016

NASA Systems Engineering Research Consortium: Defining the Path to Elegance in Systems

The NASA Systems Engineering Research Consortium was formed at the end of 2010 to study the approaches to producing elegant systems on a consistent basis. This has been a transformative study looking at the engineering and organizational basis of systems engineering. The consortium has engaged in a variety of research topics to determine the path to elegant systems. In the second year of the consortium, a systems engineering framework emerged which structured the approach to systems engineering and guided our research. This led in the third year to set of systems engineering postulates that the consortium is continuing to refine. The consortium has conducted several research projects that have contributed significantly to the understanding of systems engineering. The consortium has surveyed the application of the NASA 17 systems engineering processes, explored the physics and statistics of systems integration, and considered organizational aspects of systems engineering discipline integration. The systems integration methods have included system energy analysis, Akaike Information Criteria (AIC), State Variable Analysis, Multidisciplinary Coupling Analysis (MCA), Multidisciplinary Design Optimization (MDO), System Cost Modeling, System Robustness, and Value Modeling. Organizational studies have included the variability of processes in change evaluations, margin management within the organization, information theory of board structures, social categorization of unintended consequences, and initial looks at applying cognitive science to systems engineering. Consortium members have also studied the bidirectional influence of policy and law with systems engineering.

Watson, Michael D.↗
NASA NTRS2020

Georgia Energy III Project Summary - Identifying Habitat and Solar Site Conflict in Georgia by Developing an Environmental Sensitivity Public Mapping Too

The rapid expansion of the solar industry across the state of Georgia has a detrimental effect on the habitats of keystone and threatened species, such as the gopher tortoise (Gopherus polyphemus) and the American black bear (Ursus americanus). NASA DEVELOP collaborated with the Georgia Chapter of The Nature Conservancy (TNC) and the Georgia Department of Natural Resources to continue the research from two previous NASA DEVELOP projects in 2017. The team worked to assess the conflict between solar suitability and environmentally sensitive areas with the Land-Use Conflict Identification Strategy (LUCIS) and to determine how conflict has changed since the 2017 analysis. The project utilized Terra/Aqua Clouds and the Earth's Radiant Energy System (CERES) satellite data and other ancillary datasets to conduct and compare a general statewide LUCIS analysis from 2017 to 2019 and to complete an in-depth LUCIS analysis of Georgia’s fastest-growing solar counties—Taylor, Twiggs, Decatur, and Brooks. The analysis indicated that between 2017 and 2019, the entire state saw high conflict areas increase by 38%. Project partners will use these findings to target areas for promotion of conservation policy and education efforts. The team also provided the TNC with a publicly available web application, called the Environmental Sensitivity Mapping Tool (ESMT), that can be updated as new data are released. The ESMT will be used to educate interest groups, such as solar developers and conservationists, to help them recognize and mitigate the negative effects of solar development on the environment.

DEVELOP Project Summary↗
NASA NTRS2016

Global Carbon Budget 2016

Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere the global carbon budget is important to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we describe data sets and methodology to quantify all major components of the global carbon budget, including their uncertainties, based on the combination of a range of data, algorithms, statistics, and model estimates and their interpretation by a broad scientific community. We discuss changes compared to previous estimates and consistency within and among components, alongside methodology and data limitations. CO2 emissions from fossil fuels and industry (EFF) are based on energy statistics and cement production data, respectively, while emissions from land-use change (ELUC), mainly deforestation, are based on combined evidence from land-cover change data, fire activity associated with deforestation, and models. The global atmospheric CO2 concentration is measured directly and its rate of growth (GATM) is computed from the annual changes in concentration. The mean ocean CO2 sink (SOCEAN) is based on observations from the 1990s, while the annual anomalies and trends are estimated with ocean models. The variability in SOCEAN is evaluated with data products based on surveys of ocean CO2 measurements. The global residual terrestrial CO2 sink (SLAND) is estimated by the difference of the other terms of the global carbon budget and compared to results of independent dynamic global vegetation models. We compare the mean land and ocean fluxes and their variability to estimates from three atmospheric inverse methods for three broad latitude bands. All uncertainties are reported as +/- 1(sigma), reflecting the current capacity to characterize the annual estimates of each component of the global carbon budget. For the last decade available (2006-2015), EFF was 9.3+/-0.5 GtC/yr, ELUC 1.0+/-0.5 GtC/yr,GATM 4.5+/-0.1 GtC/yr, SOCEAN 2.6+/-0.5 GtC/yr, and SLAND 3.1+/-0.9 GtC/yr. For year 2015 alone, the growth in EFF was approximately zero and emissions remained at 9.9+/-0.5 GtC/yr, showing a slowdown in growth of these emissions compared to the average growth of 1.8/yr that took place during 2006-2015.Also, for 2015, ELUC was 1.3+/-0.5 GtC/yr, GATM was 6.3+/-0.2 GtC/yr, SOCEAN was 3.0+/-0.5 GtC/yr, and SLAND was 1.9+/-0.9 GtC/yr. GATM was higher in 2015 compared to the past decade (2006-2015), reflecting a smaller SLAND for that year. The global atmospheric CO2 concentration reached 399.4+/-0.1 ppm averaged over 2015. For 2016, preliminary data indicate the continuation of low growth in EFF with +0.2% (range of -1.0 to +1.8% ) based on national emissions projections for China and USA, and projections of gross domestic product corrected for recent changes in the carbon intensity of the economy for the rest of the world. In spite of the low growth of EFF in 2016, the growth rate in atmospheric CO2 concentration is expected to be relatively high because of the persistence of the smaller residual terrestrial sink (SLAND) in response to El Nino conditions of 2015-2016. From this projection of EFF and assumed constant ELUC for 2016, cumulative emissions of CO2 will reach 565+/-55 GtC (2075+/-205 GtCO2) for 1870-2016, about 75% from EFF and 25% from ELUC. This living data update documents changes in the methods and data sets used in this new carbon budget compared with previous publications of this data set.

Quéré, Corinne Le↗
NASA NTRS1994

Attitude stability of a spinning spacecraft during appendage deployment/retraction

The work presented is motivated by the need for a national satellite rescue policy, not the ad hoc policy now in place. In studying different approaches for a national policy, the issue of capture and stabilization of a tumbling spacecraft must be addressed. For a rescue mission involving a tumbling spacecraft, it may be advantageous to have a rescue vehicle which is compact and 'rigid' during the rendezvous/capture phase. After capture, passive stabilization techniques could be utilized as an efficient means of detumbling the resulting system (i.e., both the rescue vehicle and captures spacecraft). Since the rescue vehicle is initially compact and 'rigid,' significant passive stabilization through energy dissipation can only be achieved through the deployment of flexible appendages. Once stabilization is accomplished, retraction of the appendages before maneuvering the system to its final destination may also prove advantageous. It is therefore of paramount interest that we study the effect of appendage deployment/retraction on the attitude stability of a spacecraft. Particular interest should be paid to appendage retraction, since if this process is destabilizing, passive stabilization as proposed may not be useful. Over the past three decades, it has been an 'on-again-off-again affair' with the problem of spacecraft appendage deployment. In most instances, these studies have been numerical simulations of specific spacecraft configurations for which there were specific concerns. The primary focus of these studies was the behavior of the appendage during deployment; the effects of appendage retraction was considered only in one of these studies. What is missing in the literature is a thorough study of the effects of appendage deployment/retraction on the attitude stability of a spacecraft. This paper presents a rigorous analysis of the stability of a spinning spacecraft during the deployment or the retraction of an appendage. The analysis is simplified such that meaningful insights into the problem can be inferred; it is not overly simplified such that critical dynamical behavior is neglected. The system is analyzed assuming that the spacecraft hub is rigid. The appendage deployment mechanism is modeled as a point mass on a massless rod whose length undergoes prescribed changes. Simplified flexibility effects of the appendage are included. The system is examined for stability by linearizing the equations in terms of small deviations from steady, noninterfering coning motion. Routh's procedure for analyzing small deviations from steady motion in dynamical systems is utilized in the analysis. The system of equations are nondimensionalized to facilitate parametric studies. The results are presented in terms of a reduced number of nondimensional parameters so that some general conclusions may be drawn. Verification of the linear analysis is presented through numerical simulations of the complete nonlinear, nonautonomous, coupled equations.

Fitz-Coy, Norman↗
NASA NTRS1996

Coordinated Fuel Cell System Programs for Government and Commercial Applications: Are We in a New Era?

Though the fuel cell was invented in 1839, it was not until the early 1960's that the fuel cell power system was developed and used for a real application, for the NASA Space Mission Gemini. Unfortunately, fuel cell power systems did not, as a result, become in widespread use. Nevertheless, a great deal of progress has been made by both government and industry, culminating in many successful fuel cell power system demonstrations. Initially, each government agency and each private organization went its own way. Later, it became evident that coordination among programs was essential. An overview is presented of the current coordinated efforts by government and industry in fuel cells, with a sufficient historical background. The primary barriers to coordination of programs were institutional and differing application requirements. Initially, in the institutional area, it was the energy crisis and the formation of DOE which fostered close working relationships among government, manufacturers, and users. The authors discuss the fuel cell power system programs (of NASA, DOE, DOT, DOC, EPRI, GRI, industry, and universities), including missions and applications, technology advances, and demonstrations. The discussion covers the new Solar Regenerative Fuel Cell (RFC) program which has space, defense, and commercial terrestrial applications, and which is an excellent example of both program coordination and the Clinton Administration's dual-use application policy.

Warshay, Marvin↗
NASA NTRS2004

From Runway to Orbit: Reflections of a NASA Engineer

In his remarkable memoir Runway to Orbit, Dr. Kenneth W. Iliff - the recently retired Chief Scientist of the NASA Dryden Flight Research Center- tells a highly personal, yet a highly persuasive account of the last forty years of American aeronautical research. His interpretation of events commands respect, because over these years he has played pivotal roles in many of the most important American aeronautics and spaceflight endeavors. Moreover, his narrative covers much of the second half of the first 100 years of flight, a centennial anniversary being celebrated this year. aerospace knowledge. He arrived at the then NASA Flight Research Center in 1962 as a young aeronautical engineer and quickly became involved in two of the seminal projects of modern flight, the X-15 and the lifting bodies. In the process, he pioneered (with Lawrence Taylor) the application of digital computing to the reduction of flight data, arriving at a method known as parameter estimation, now applied the world over. Parameter estimation not only enabled researchers to acquire stability and control derivatives from limited flight data, but in time allowed them to obtain a wide range of aerodynamic effects. Although subsequently involved in dozens of important projects, Dr. Iliff devoted much of his time and energy to hypersonic flight, embodied in the Shuttle orbiter (or as he refers to it, the world s fastest airplane). To him, each Shuttle flight, instrumented to obtain a variety of data, represents a research treasure trove, one that he has mined for years. This book, then, represents the story of Dr. Ken Iliff s passion for flight, his work, and his long and astoundingly productive career. It can be read with profit not just by scientists and engineers, but equally by policy makers, historians, and journalists wishing to better comprehend advancements in flight during the second half of the twentieth century. Dr. Iliff's story is one of immense contributions to the nation s repository of

Iliff, Kenneth W.↗
NASA NTRS1978

A preference-ordered discrete-gaming approach to air-combat analysis

An approach to one-on-one air-combat analysis is described which employs discrete gaming of a parameterized model featuring choice between several closed-loop control policies. A preference-ordering formulation due to Falco is applied to rational choice between outcomes: win, loss, mutual capture, purposeful disengagement, draw. Approximate optimization is provided by an active-cell scheme similar to Falco's obtained by a 'backing up' process similar to that of Kopp. The approach is designed primarily for short-duration duels between craft with large-envelope weaponry. Some illustrative computations are presented for an example modeled using constant-speed vehicles and very rough estimation of energy shifts.

Kelley, H. J.↗
NASA NTRS2008

Development Status of the CECE Cryogenic Deep Throttling Demonstrator Engine

As one of the first technology development programs awarded by NASA under the U.S. Space Exploration Policy (USSEP), the Pratt & Whitney Rocketdyne (PWR) Deep Throttling, Common Extensible Cryogenic Engine (CECE) program was selected by NASA in November 2004 to begin technology development and demonstration toward a deep throttling, cryogenic engine supporting ongoing trade studies for NASA's Lunar Lander descent stage. The CECE program leverages the maturity and previous investment of a flight-proven hydrogen/oxygen expander cycle engine, the PWR RLI0, to develop and demonstrate an unprecedented combination of reliability, safety, durability, throttlability, and restart capabilities in a high-energy, cryogenic engine. The testbed selected for the deep throttling demonstration phases of this program was a minimally modified RL10 engine, allowing for maximum current production engine commonality and extensibility with minimum program cost. Two series of demonstrator engine tests, the first in April-May 2006 and the second in March-April 2007, have demonstrated in excess of 10:1 throttling of the hydrogen/oxygen expander cycle engine. Both test series have explored a combustion instability ("chug") environment at low throttled power levels. These tests have provided an early demonstration of an enabling cryogenic propulsion concept with invaluable system-level technology data acquisition toward design and development risk mitigation for future CECE Demonstrator engine tests.

Source record↗
NASA NTRS2007

Swift Multi-wavelength Observing Campaigns: Strategies and Outcomes

The Swift gamma-ray burst explorer has been operating since December 2004 as both a gamma-ray burst (GRB) monitor and telescope and a multi-wavelength observatory, covering the energy range from V band and near UV to hard X rays above 150 keV. It is designed to rapidly repoint to observe newly discovered GRBs, and this maneuverability, combined with an easily changed observing program, allows Swift to also be an effective multiwavelength observatory for non-GRB targets, both as targets of opportunity and pre-planned multi-wavelength observing campaigns. Blazars are particularly attractive targets for coordinated campaigns with TeV experiments since many blazars are bright in both the hard X-ray and TeV energy ranges. Successful coordinated campaigns have included observations of 3C454.3 during its 2005 outburst. The latest Swift funding cycles allow for non- GRB related observations to be proposed. The Burst Alert Telescope on Swift also serves as a hard X-ray monitor with a public web page that includes light curves for over 400 X-ray sources and is used to alert the astronomical community about increased activity from both known and newly discovered sources. This presentation mill include Swift capabilities, strategies and policies for coordinated multi-wavelength observations as well as discussion of the potential outcomes of such campaigns.

Krimm, Hans A.↗
NASA NTRS1989

Tethers in space handbook, second edition

The Tethers in Space Handbook, Second Edition represents an update to the initial volume issued in September 1986. As originally intended, this handbook is designed to serve as a reference manual for policy makers, program managers, educators, engineers, and scientists alike. It contains information for the uninitiated, providing insight into the fundamental behavior of tethers in space. For those familiar with space tethers, it includes a summary of past and ongoing studies and programs, a complete bibliography of tether publications, and names, addresses, and phone numbers of workers in the field. Perhaps its most valuable asset is the brief description of nearly 50 tether applications which have been proposed and analyzed over the past 10 years. The great variety of these applications, from energy generation to boosting satellites to gravity wave detection is an indication that tethers will play a significant part in the future of space development. This edition of the handbook preserves the major characteristics of the original; however, some significant rearrangements and additions have been made. The first section on Tether Programs has been brought up to date, and now includes a description of TSS-2, the aerodynamic NASA/Italian Space Agency (ASI) mission. Tether Applications follows, and this section has been substantially rearranged. First, the index and cross-reference for the applications have been simplified. Also, the categories have changed slightly, with Technology and Test changed to Aerodynamics, and the Constellations category removed. In reality, tether constellations may be applicable to many of the other categories, since it is simply a different way of using tethers. Finally, to separate out those applications which are obviously in the future, a Concepts category has been added. A new section included here on Conference Summaries recognizes the fact that the tether community is growing internationally, and that meetings provide a means of rapid communication and interaction. Finally, the Bibliography section has been considerably updated to include all known references. These are listed by author and by subject and include the papers to be presented at the Third International Conference in May 1989.

Penzo, Paul A.↗
NASA NTRS2013

XIPE the X-Ray Imaging Polarimetry Explorer

X-ray polarimetry, sometimes alone, and sometimes coupled to spectral and temporal variability measurements and to imaging, allows a wealth of physical phenomena in astrophysics to be studied. X-ray polarimetry investigates the acceleration process, for example, including those typical of magnetic reconnection in solar flares, but also emission in the strong magnetic fields of neutron stars and white dwarfs. It detects scattering in asymmetric structures such as accretion disks and columns, and in the so-called molecular torus and ionization cones. In addition, it allows fundamental physics in regimes of gravity and of magnetic field intensity not accessible to experiments on the Earth to be probed. Finally, models that describe fundamental interactions (e.g. quantum gravity and the extension of the Standard Model) can be tested. We describe in this paper the X-ray Imaging Polarimetry Explorer (XIPE), proposed in June 2012 to the first ESA call for a small mission with a launch in 2017. The proposal was, unfortunately, not selected. To be compliant with this schedule, we designed the payload mostly with existing items. The XIPE proposal takes advantage of the completed phase A of POLARIX for an ASI small mission program that was cancelled, but is different in many aspects: the detectors, the presence of a solar flare polarimeter and photometer and the use of a light platform derived by a mass production for a cluster of satellites. XIPE is composed of two out of the three existing JET-X telescopes with two Gas Pixel Detectors (GPD) filled with a He-DME mixture at their focus. Two additional GPDs filled with a 3-bar Ar-DME mixture always face the Sun to detect polarization from solar flares. The Minimum Detectable Polarization of a 1 mCrab source reaches 14 in the 210 keV band in 105 s for pointed observations, and 0.6 for an X10 class solar flare in the 1535 keV energy band. The imaging capability is 24 arcsec Half Energy Width (HEW) in a Field of View of 14.7 arcmin 14.7 arcmin. The spectral resolution is 20 at 6 keV and the time resolution is 8 s. The imaging capabilities of the JET-X optics and of the GPD have been demonstrated by a recent calibration campaign at PANTER X-ray test facility of the Max-Planck-Institut fr extraterrestrische Physik (MPE, Germany). XIPE takes advantage of a low-earth equatorial orbit with Malindi as down-link station and of a Mission Operation Center (MOC) at INPE (Brazil). The data policy is organized with a Core Program that comprises three months of Science Verification Phase and 25 of net observing time in the following 2 years. A competitive Guest Observer program covers the remaining 75 of the net observing time.

Astronomy X-ray Polarimetry↗
NASA NTRS1983

Air Force Logistics Command (AFLC) solar thermal plant

The plant proved its capability to deliver the desired energy product in a USAF industrial environment. The collector proved capable of energy conversion at insolation levels up to 25% below design minimum. The plant and the project were negatively affected by severe winter weather, with total insolation during the test period 60 percent less than the expected value. Environmental effects reduced plant availability to 55 percent. Only five, minimally good operating days were experienced during the test period. The subsequent lack of performance data prohibits the drawing of general conclusions regarding system performance. System operability was rated generally high. The only inhibiting factor was the difficulty in procuring replacement parts for rapid repair under USAF stockage and procurement policies. No inherently serious system failures were recorded, although a thermostatic valve malfunction in the freeze protection system ultimately took 30 days to repair.

Source record↗
NASA NTRS2017

Controlling Tensegrity Robots through Evolution using Friction based Actuation

Traditional robotic structures have limitations in planetary exploration as their rigid structural joints are prone to damage in new and rough terrains. In contrast, robots based on tensegrity structures, composed of rods and tensile cables, offer a highly robust, lightweight, and energy efficient solution over traditional robots. In addition tensegrity robots can be highly configurable by rearranging their topology of rods, cables and motors. However, these highly configurable tensegrity robots pose a significant challenge for locomotion due to their complexity. This study investigates a control pattern for successful locomotion in tensegrity robots through an evolutionary algorithm. A twelve-rod hardware model is rapidly prototyped to utilize a new actuation method based on friction. A web-based physics simulation is created to model the twelve-rod tensegrity ball structure. Square-waves are used as control policies for the actuators of the tensegrity structure. Monte Carlo trials are run to find the most successful number of amplitudes for the square-wave control policy. From the results, an evolutionary algorithm is implemented to find the most optimized solution for locomotion of the twelve-rod tensegrity structure. The software pattern coupled with the new friction based actuation method can serve as the basis for highly efficient tensegrity robots in space exploration.

Tensegrit↗