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NASA NTRS2004

Determine Important Nuclear Fragmentation Processes for Space Radiation Protection in Human Space Explorations

Space radiation from cosmic ray particles is one of the main challenges for long-term human space explorations such as a permanent moon base or a trip to Mars. Material shielding may provide significant radiation protection to astronauts, and models have been developed in order to evaluate the effectiveness of different shielding materials and to predict radiation environment inside the spacecraft. In this study we determine the nuclear fragmentation cross sections which will most effect the radiation risk behind typical radiation shielding materials. These cross sections thus need more theoretical studies and accurate experimental measurements in order for us to more precisely predict the radiation risk in human space explorations.

Lin, Zi-wei↗

NASA NTRS2004

Determine Important Nuclear Fragmentation Processes for Space Radiation Protection in Human Space Explorations

Space radiation from cosmic ray particles is one of the main challenges for long-term human space explorations such as a permanent moon base or a trip to Mars. Material shielding may provide significant radiation protection to astronauts, and models have been developed in order to evaluate the effectiveness of different shielding materials and to predict radiation environment inside the spacecraft. In this study we determine the nuclear fragmentation cross sections which will most affect the radiation risk behind typical radiation shielding materials. These cross sections thus need more theoretical studies and accurate experimental measurements in order for us to more precisely predict the radiation risk in human space exploration.

Lin, Zi-Wei↗

NASA NTRS2004

Determine Important Nuclear Fragmentation Processes for Space Radiation Protection in Human Space Explorations

Space radiation from cosmic ray particles is one of the main challenges for long-term human space explorations such as a permanent moon base or a trip to Mars. Material shielding may provide significant radiation protection to astronauts, and models have been developed in order to evaluate the effectiveness of different shielding materials and to predict radiation environment inside the spacecraft. In this study we determine the nuclear fragmentation cross sections which will most affect the radiation risk behind typical radiation shielding materials. These cross sections thus need more theoretical studies and accurate experimental measurements in order for us to more precisely predict the radiation risk in human space explorations.

Lin, Zi-Wei↗

NASA NTRS2004

Swift Gamma-Ray Burst Explorer: Mission Design for Rapid, Accurate Location of Gamma-ray Bursts

The Swift Gamma-ray Burst Explorer is a NASA Mid-sized Explorer (MIDEX) with the primary mission of determining the origins of Gamma-Ray Bursts (GRBs). It will be the first mission to autonomously respond to newly-discovered GRBs and provide immediate follow-up narrow field instruments capable of multi-wavelength (UV, Optical, X-ray) observations. The characteristics of GRBs that are the key mission design drivers, are their non-repeating and brief duration bursts of multi-wavelength photons. In addition, rapid notification of the location and characteristics of the GRBs to ground-and-space- based observatories drive the end-to-end data analysis and distribution requirements. The Swift mission is managed by the GSFC, and includes an international team of contributors that each bring their unique perspective that have proven invaluable to the mission. The spacecraft bus, provided by Spectrum Astro, Inc. was procured through a Rapid Spacecraft Development Office (RSDO) contract by the GSFC. There are three instruments: the Burst Alert Telescope (BAT) provided by the GSFC; the X-Ray Telescope (XRT) provided by a team led by the Pennsylvania State University (PSU); and the Ultra-Violet Optical Telescope (UVOT), again managed by PSU. The Mission Operations Center (MOC) was developed by and is located at PSU. Science archiving and data analysis centers are located at the GSFC, in the UK and in Italy.

Bundas, David J.↗

NASA NTRS2004

SILVER: Surface Imaging for Lunar Volatiles, Resources, and Exploration

The Surface Imaging for Lunar Volatiles, Exploration, and Resources (SILVER) instrument is a proposed imaging investigation for the 2008 Lunar Reconnaissance Orbiter (LRO) mission. SILVER and its experienced Measurement Team will prepare for and support future lunar human exploration activities, especially landing site identification and certification on the basis of potential resources. SILVER combines a high-resolution pushbroom visible imaging channel (SILVER-HR) and a wide-field-of-view (45 deg) framing imaging channel (SILVER-WF). SILVER-HR will obtain a single-detector 6 km imaging swath of 12,228 pixels at 0.5 m/pixel to image greater than 100 sq km target areas from 50 km altitude, imaging greater than 15% the lunar surface during a 1 year nominal mission. SILVER-HR has excellent stray-light rejection and its imaging detector has selectable time delay integration (TDI) with up to 128 stages for extreme low-light sensitivity, permitting direct imaging of permanently shadowed polar regions in scattered sunlight or earthshine. SILVER-WF will obtain geodetic framing images in a 2048 x 2048 format at 20m/pixel, with 60% along-track overlap stereo for imaging context and for derivation of a global digital elevation model of meter-scale lunar topography.

Pappalardo, R. T.↗

NASA NTRS1994

Crew systems: integrating human and technical subsystems for the exploration of space

Space exploration missions will require combining human and technical subsystems into overall "crew systems" capable of performing under the rigorous conditions of outer space. This report describes substantive and conceptual relationships among humans, intelligent machines, and communication systems, and explores how these components may be combined to complement and strengthen one another. We identify key research issues in the combination of humans and technology and examine the role of individual differences, group processes, and environmental conditions. We conclude that a crew system is, in effect, a social cyborg, a living system consisting of multiple individuals whose capabilities are extended by advanced technology.

NASA Discipline Space Human Factors↗

NASA NTRS2005

Teaming for Exploration

A multibillion-dollar NASA contracting effort, the largest since the Apollo, shuttle, and space station developments, is formally underway with the release of the draft request for proposals for the Crew Exploration Vehicle (CEV) to replace the shuttle and eventually return astronauts to the Moon as a stepping-stone to Mars. With guidance from the draft request for proposals (RFP) now in hand, contractors are beginning a flurry of activity to posture for formal bids and to align their earlier in-house concepts with major new exploration program specifics, including strong guidelines on managing cost and risk. And Lockheed Martin will announce this week that it is teaming with EADS Space Transportation for the CEV contract. Should this team win, Europe's largest aerospace contractor would be in line for a key role in developing a replacement for the shuttle and renewed human operations on the lunar surface.

Covault, Craig↗

NASA NTRS2005

Materials Challenges in Space Exploration

United States civil space program administered by National Aeronautics and Space Administration has a new strategic direction to explore the solar system. This new 'vision for space exploration' encompasses a broad range of human and robotic missions, including the Moon. Mars and destinations beyond. These missions require advanced systems and capabilities that will accelerate the development of many critical technologies, including advanced materials and structural concepts. Specifically, it is planned to develop high-performance materials for vehicle structures, propulsion systems, and space suits; structural concepts for modular assembly for space infrastructure: lightweight deployable and inflatable structures for large space systems and crew habitats; and highly integrated structural systems and advanced thermal management systems for reducing launch mass and volume. This paper will present several materials challenges in advanced space systems-high performance structural and thermal materials, space durable materials, radiation protection materials, and nano-structural materials. Finally, the paper will take a look at the possibility of utilizing materials in situ, i.e., processing materials on the surface of the Moon and Mars.

Bhat, Biliyar N.↗

NASA NTRS2005

Materials Challenges in Space Exploration

United States civil space program administered by National Aeronautics and Space Administration (NASA) has a new strategic direction to explore the solar system. This new 'vision for space exploration' encompasses a broad range of human and robotic missions, including the Moon, Mars and destinations beyond. These missions require advanced systems and capabilities that will accelerate the development of many critical technologies, including advanced materials and structural concepts. Specifically, it is planned to develop high-peformance materials for vehicle structures, propulsion systems, and space suits; structural concepts for modular assembly for space infrastructure; lightweight deployable and inflatable structures for large space systems and crew habitats; and highly integrated structural systems and advanced thermal management systems for reducing launch mass and volume. This paper will present several materials challenges in advanced space systems-high performance structural and thermal materials, space durable materials, radiation protection materials, and nano- structural materials. The paper will also address smart materials and structures and examine space environmental effects on materials and methods of mitigating them. Finally, the paper will take a look at the possibility of utilizing materials in situ, i.e., processing and using desired materials on the surface of the Moon and Mars.

Bhat, Biliyar N.↗

NASA NTRS2004

The Human Exploration Initative: Space Radiation Measurement Needs

NASA's Space Exploration Initiative envisions human exploration missions to the Moon and Mars. To accomplish these missions safely, they must be designed and planned to limit the acute and long term health risks posed by ionizing radiation. This requires knowledge of the relevant components of the ionizing radiation environment in deep space, on the Moon and on Mars. In this talk we will identify what must be known about the ionizing radiation environment, discuss what knowledge already exists and suggest what new measurements may be needed before manned missions can be conducted safely.

Adams, Jim↗

NASA NTRS2004

The In-Space Soldering Investigation: Research Conducted on the International Space Station in Support of NASA's Exploration Initiative

Soldering is a well established joining and repair process that is of particular importance in the electronics industry. Still. internal solder joint defects such as porosity are prevalent and compromise desired properties such as electrical/thermal conductivity and fatigue strength. Soldering equipment resides aboard the International Space Station (ISS) and will likely accompany Exploration Missions during transit to, as well as on, the moon and Mars. Unfortunately, detrimental porosity appears to be enhanced in lower gravity environments. To this end, the In-Space Soldering Investigation (ISSI) is being conducted in the Microgravity Workbench Area (MWA) aboard the ISS as "Saturday Science" with the goal of promoting our understanding of joining techniques, shape equilibrium, wetting phenomena, and microstructural development in a microgravity environment. The work presented here will focus on direct observation of melting dynamics and shape determination in comparison to ground-based samples, with implications made to processing in other low-gravity environments. Unexpected convection effects, masked on Earth, will also be shown as well as the value of the ISS as a research platform in support of Exploration Missions.

Grugel, R. N.↗

NASA NTRS2004

Smart Structures for Vibration Control on Long-Term Space Exploration and Habitation Missions

The current vision for space exploration focuses on human missions to the Moon, Mars, and beyond. To support these goals, it is certain that new vehicles and intermediate bases will be developed, whether that means simply re-direction of the ISS as a "mission research facility" or construction of a lunar base. Since these facilities are expected to be constructed from inherently light-weight materials, this work examines some of the potential sources of vibration and noise as well as means for controlling these vibrations. Many of the operating components within these facilities, such as pumps, fans, and motors, will produce vibrations during operation. These vibrations become structure in which they are housed. Resonances can impact acoustic noise levels and noise quality within the environment, possibly affecting crew health and productivity. For long-term missions in particular, it is expected that crew members will spend significant portions of their time restrained in the structure, such as in seats. As a result, the general health and well-being of the crew can be improved by limiting the harmful effects of human exposure to long-term audible and tactile vibration input. Besides the human factor, this work also examines some operational considerations in which vibrations play an important role. Vibrations can impact the environment for science and in-situ manufacturing research within these vehicles. Since a benign vibratory environment is beneficial for most types of science experiments, there is a need for various forms of vibration control. Because the operational characteristics of a vehicle can change during a long-term mission, it is further expected that the characteristics of many of the vibratory excitations will change with time. Consequently, the form of vibration control needed to improve overall habitability and usefulness of the vehicle or element for exploration missions will rely to some degree on the vibration control system's ability to adapt. To address these needs, this work also examines the development and use of smart materials to tune the dynamic characteristics of the structure in a passive sense. One prime example is the use of an adaptive electrical shunt connected to a piezoelectric patch in order to provide tuned passive vibration damping. The work also examines the use of active vibration control, such as by applying power to that same piezoelectric patch. The overall goal is to examine the use of smart structures that can react to the environment thereby improving the overall living, working, and learning environment for these long-term missions.

Gattis, Christy B.↗

NASA NTRS2005

Development of Spacecraft to Exploit Electric Propulsion for Outer Planetary Exploration

Outer planetary exploration spacecraft have relied on Radioisotope Power Systems (RPS) to provide power. This is necessary as solar power is not useful beyond the inner planets. For propulsion these spacecraft have made use of chemical systems. A study was undertaken to look at the possibility of designing a spacecraft for outer planetary exploration that would use an RPS in combination with Electric Propulsion. That is, the RPS would be the sole power provider to the EP system. Recent improvements in RPS s have made Radioisotope Electric Propulsion (REP) more of a possibility. The combined power and propulsion technologies of REP and a direct trajectory would potentially enable a new class of missions - high delta V, beyond Mars orbit for a small spacecraft primarily suited for small body capture (orbit capture or co-orbit). A study was undertaken to evaluate the feasibility of a REP spacecraft for a selected representative mission of this type. To evaluate the potential of these technologies, a design reference mission was established and a conceptual design of a spacecraft developed. The following paper describes the Ion Propulsion System, one particular subsystem onboard of the spacecraft.

Roche, Joseph M.↗

NASA NTRS2004

Swift Gamma-Ray Burst Explorer: Mission Design for Rapid, Accurate Location of Gamma-ray Bursts

Bundas, David J.↗

NASA NTRS2005

Swift Gamma-ray Burst Explorer: Mission Design for Rapid, Accurate Location of Gamma-ray Bursts

Bundas, David J.↗

NASA NTRS2005

A Management Model for International Participation in Space Exploration Missions

This paper proposes an engineering management model for NASA's future space exploration missions based on past experiences working with the International Partners of the International Space Station. The authors have over 25 years of combined experience working with the European Space Agency, Japan Aerospace Exploration Agency, Canadian Space Agency, Italian Space Agency, Russian Space Agency, and their respective contractors in the design, manufacturing, verification, and integration of their elements electric power system into the United States on-orbit segment. The perspective presented is one from a specific sub-system integration role and is offered so that the lessons learned from solving issues of technical and cultural nature may be taken into account during the formulation of international partnerships. Descriptions of the types of unique problems encountered relative to interactions between international partnerships are reviewed. Solutions to the problems are offered, taking into consideration the technical implications. Through the process of investigating each solution, the important and significant issues associated with working with international engineers and managers are outlined. Potential solutions are then characterized by proposing a set of specific methodologies to jointly develop spacecraft configurations that benefits all international participants, maximizes mission success and vehicle interoperability while minimizing cost.

George, Patrick J.↗

NASA NTRS2005

Electric Propulsion Concepts Enabled by High Power Systems for Space Exploration

This paper describes the latest development in electric propulsion systems being planned for the new Space Exploration initiative. Missions to the Moon and Mars will require these new thrusters to deliver the large quantities of supplies that would be needed to support permanent bases on other worlds. The new thrusters are also being used for unmanned exploration missions that will go to the far reaches of the solar system. This paper is intended to give the reader some insight into several electric propulsion concepts their operating principles and capabilities, as well as an overview of some mission applications that would benefit from these propulsion systems, and their accompanying advanced power systems.

Gilland, James↗

NASA NTRS2005

Dynamic Dust Accumulation and Dust Removal Observed on the Mars Exploration Rover Magnets

The Mars Exploration Rovers each carry a set of Magnetic Properties Experiments designed to investigate the properties of the airborne dust in the Martian atmosphere. It is a preferred interpretation of previous experiments that the airborne dust in the Martian atmosphere is primarily composed by composite silicate particles containing one or more highly magnetic minerals as a minor constituent. The ultimate goal of the magnetic properties experiments on the Mars Exploration Rover mission is to provide some information/ constraints on whether the dust is formed by volcanic, meteoritic, aqueous, or other processes. The first problem is to identify the magnetic mineral(s) in the airborne dust on Mars. While the overall results of the magnetic properties experiments are presented in, this abstract will focus on dust deposition and dust removal on some of the magnets.

Bertelsen, P.↗