International space station

NASA is developing an experimental flight payload (referred to as the Space Communication and Navigation (SCAN) Test Bed) to investigate software defined radio (SDR), networking, and navigation technologies, operationally in the space environment. The payload consists of three software defined radios each compliant to NASA s Space Telecommunications Radio System Architecture, a common software interface description standard for software defined radios. The software defined radios are new technology developments underway by NASA and industry partners. Planned for launch in early 2012, the payload will be externally mounted to the International Space Station truss and conduct experiments representative of future mission capability.

The National Aeronautical and Space Administration (NASA) recently launched a new software defined radio research test bed to the International Space Station. The test bed, sponsored by the Space Communications and Navigation (SCaN) Office within NASA is referred to as the SCaN Testbed. The SCaN Testbed is a highly capable communications system, composed of three software defined radios, integrated into a flight system, and mounted to the truss of the International Space Station. Software defined radios offer the future promise of in-flight reconfigurability, autonomy, and eventually cognitive operation. The adoption of software defined radios offers space missions a new way to develop and operate space transceivers for communications and navigation. Reconfigurable or software defined radios with communications and navigation functions implemented in software or VHDL (Very High Speed Hardware Description Language) provide the capability to change the functionality of the radio during development or after launch. The ability to change the operating characteristics of a radio through software once deployed to space offers the flexibility to adapt to new science opportunities, recover from anomalies within the science payload or communication system, and potentially reduce development cost and risk by adapting generic space platforms to meet specific mission requirements. The software defined radios on the SCaN Testbed are each compliant to NASA's Space Telecommunications Radio System (STRS) Architecture. The STRS Architecture is an open, non-proprietary architecture that defines interfaces for the connections between radio components. It provides an operating environment to abstract the communication waveform application from the underlying platform specific hardware such as digital-to-analog converters, analog-to-digital converters, oscillators, RF attenuators, automatic gain control circuits, FPGAs, general-purpose processors, etc. and the interconnections among different radio components. NASA is inviting experimenters from industry, academia, and other agencies to use the SCaN Testbed. On the flight system, the three software defined radios (SDR) and a portion of the flight computer or avionics, is available to experimenters to develop, test, and operate new SDR applications in-orbit. Experiment operations include inflight reconfiguration of the SDR waveform functions, and communications at S-band or Ka-band with NASA's inspace Tracking and Data Relay Satellite Network, or at Sband direct from the SCaN Tested to any Earth-based compatible ground station. One of the SDRs also receives GPS frequencies at the L1, L2c, and L5 frequencies. Various GPS waveforms are possible using the reconfigurable digital processing of the SDR. Command, control, and experiment operations occur from the Glenn Research Center in Cleveland, Ohio. NASA provides the ground connections between the Experiment Center and the uplink site to the TDRSS Network at White Sands. New Mexico. Experimenters are encouraged to use the SCaN Testbed for a variety of research topics and applications. NASA will provide access and support to both the on-orbit testbed, and ground-based systems for development and verification activities. This paper will provide a description of the SCaN Testbed, the SDR capabilities, and the ground systems available to potential experimenters. Unique aspects of SDR developments, verification, and operations will be discussed.

The influence of geometry model approximations on Geant4 Monte Carlo simulation results of the radiation environment on-board the Columbus module of the International Space Station (ISS) has been investigated. Three geometry models of Columbus with different levels of detail and a geometry model of ISS have been developed. These geometries have been used for Geant4 simulations of the radiation environment inside Columbus induced by trapped protons and Galactic Cosmic Ray protons. Simulated dose rates and particle spectra on-board Columbus for each of the three Columbus models, with or without the ISS geometry model included, are presented and compared. From comparisons of simulated dose rates and particle spectra for the three different geometry models it was found that the most detailed geometry model (750 volumes) produced results similar to a much less detailed model (23 volumes). The most detailed geometry model was concluded to be a sufficiently detailed approximation of the physical Columbus for the purpose of proton induced space radiation studies. The simulated dose rates are compatible with measurements on-board the ISS. The simulation results also show that an increase in shielding thickness decreases the simulated dose rate induced by trapped protons. For Galactic Cosmic Ray protons the dose rate remains unchanged or is slightly increased.

Advanced nickel-based superalloys combine excellent high-temperature mechanical strength, creep resistance, and toughness, and therefore find applications in next-generation aircraft engines and turbines for land-based power generators. The related fabrication processes are complex, time consuming, and costly, making it necessary to perform supporting computer simulations of the heat and material flow in the melt before and during crystallization. Such models are based on reliable thermophysical property data in the solid and liquid phase. However, measurements of surface-and volume-dependent properties, such as liquid surface tension, viscosity, and specific heat of these complex liquid metal alloys, are very challenging, due to the melts high chemical reactivity at temperatures of interest. The method of choice is electromagnetic levitation, a containerless method. The measurements of surface tension, viscosity, mass density, and specific heat capacity, performed in the electromagnetic levitator (EML) on board the Space Laboratory Columbus in the International Space Station (ISS), are presented and discussed.

NASA Human Research Program
Investigators’ Workshop:January 28-31, 2025 - Galveston Island Convention Center-Galveston, Texas
Sponsored by: NASA Human Research Program

Reference 1:

Title: Adapting to Weightlessness: The Influence of Real and Simulated Microgravity on Mammalian Extracellular Matrix Dynamics.
Authors: Jhan Sebastian Saavedra Torres, M. A. Guayambuco Medina, J. C. Álvarez Camargo, M. Á. García Parra, C. Salguero.
Code: SESS-246.
Abstract: This research on the extracellular matrix (ECM) under microgravity conditions utilized various molecular techniques to assess changes in cellular dynamics and the expression of essential proteins. The findings underscore the urgent need to understand how microgravity affects the ECM, which is crucial for safeguarding astronaut health during extended space missions and developing effective intervention and recovery strategies.
Reference 2:

Title: Alterations in the Uptake and Release of Small Molecules in Cells Exposed to Simulated Microgravity.
Authors: Jhan Sebastian Saavedra Torres, M. A. Guayambuco Medina, M. Á. García Parra, C. Salguero.
Code: SESS-67.
Abstract: In a simulated microgravity environment, cells experience significant changes in their ability to absorb and release small molecules, which is essential for their normal functioning. Studying how microgravity influences nutrient absorption, waste elimination, and drug efficacy allows the identification of potential problems that may arise during long-term space missions.

Value hierarchies, coping patterns, and motivations of International Space Station (ISS) astronauts were examined in the present set of studies. Thematic content analysis was applied for references to above psychosocial markers in narratives (media interviews, journals, and oral histories) of 46 astronauts from the ISS expeditions. Results revealed that the five most mentioned universal values were identified as Achievement, Security, Benevolence, Universalism, and Self Direction. In regards to coping strategies, astronauts are more likely to use problem-oriented than emotionoriented strategies. The top three coping strategies astronauts relied on were Seeking Social Support, Planful Problem Solving, and reference to Luck. In addition, astronauts were most likely to seek support in the form of personal information from their crew and ground control. Astronauts were most likely to be motivated by Achievement followed by Affiliation and Power. The role of leadership aboard the station was also examined. It was concluded that commanders were most likely assuming the supportive leadership role. The findings have important implications in understanding crew relations prior to and during the mission.

Research has demonstrated that the motive triad of needs for achievement, power, and affiliation can predict variables such as occupational success and satisfaction, innovation, aggressiveness, susceptibility to illness, cooperation, conformity, and many others. The present study documents the motivational profiles of astronauts at three stages of their expedition. Thematic content analysis was employed for references to Winter's well-established motive markers in narratives (media interviews, journals, and oral histories) of 46 astronauts participating in International Space Station (ISS) expeditions. Significant pre-flight differences were found in relation to home agency and job status. NASA astronauts, compared with those from the Russian Space Agency, are motivated by higher need for power, as are commanders in comparison to flight engineers. The need for affiliation motive showed a significant change from pre-flight to in-flight stages. The implications of the relationship between the motivational profile of astronauts and the established behavioural correlates of such profiles are discussed.

Determination of the frequency and importance of impacts by space debris and micrometeoroids of below 1 mm in size is best achieved by examining spacecraft surfaces that have been exposed in the near-Earth orbital environment. Post-flight investigation of ...

The effect of storage in space on the stability of vitamin B complex in two commercial vitamin tablets was examined. Multiple vitamin samples returned after storage on the space shuttle and International Space Station (ISS) along with two ground control and three positive control groups were included in the study. Content of vitamin B 3 in the tablets and in vitro dissolution rate were determined using a modified high performance liquid chromatographic assay from USP/NF 2010. Results indicate that vitamin B 3 in one of the brands tested (#2) may be subject to marginal degradation after storage on ISS for 4 months as indicated by the chromatograms for all six tablets showing a split peak appearing as a notch at the peak tip. Chromatograms were not different for ground and flight samples for Brand #1 suggesting that this may be more suitable for use in space.

In the GENE experiment performed during an 11-day Soyuz Mission to the International Space Station (ISS), we intended to determine if microgravity affects Drosophila metamorphosis processes. Control experiments were performed including a 1g ground control parallel to the ISS flight samples and a Random Position Machine microgravity simulated control. A preliminary analysis of the results indicates that five hundred to one thousand genes change their expression profiles depending on the cut-off levels selected. Especially affected among them are the mitochondrial

Long duration spaceflight missions present many new challenges and payload limitations. Maintaining and utilizing finite resources during long-term spaceflight will require cyclical biological systems to both reduce and recycle materials. Biologically made plastics can be a valuable biomaterial to use during long-term space missions (e.g. Mars, lunar outpost). The aim of this project is to optimize the production and recovery of bioplastic from a genetically modified Escherichia coli (E. coli) bacterium. Improving total bioplastic production and purification procedures will enable less mass to be launched as payload aboard manned space missions, therefore reducing costs and leaving room for additional cargo pertinent to mission success. Using this biomaterial as a building block, the digital schematics for human habitats, replacement parts, or new tools can be sent directly to astronauts to be 3D printed on-demand. For this project, E. coli was cultured in 5L batch fermentations with focus on optimizing parameters that affect bioplastic production such as fermentation time, dissolved oxygen content, as well as the quality and quantity of nutrients in the aqueous growth media. Lastly, by defining the minimal media components necessary for adequate production of bioplastic, a good approximation of the effectiveness of growing E. coli using in situ resource utilization on Mars or the Moon can be determined.

Ekoplasma is a joint German-Russian project, developing the future multi-purpose laboratory for the investigation of complex plasmas under microgravity conditions aboard the International Space Station (ISS). Complex plasmas are low-temperature plasmas, consisting of neutral gas atoms, ions, electrons and micro-meter sized particles as an additional component. The particles become charged in the plasma and as a result of their mutual repulsion form an optically thin cloud that can be studied in its full spatial and dynamical complexity on the granularity scale of each particle by optical cameras. Therefore, complex plasmas allow fundamental investigations down to the kinetic level of individual particles also for a wide field of interdisciplinary topics in classical condensed matter physics. Since gravity prevents the formation of large, homogeneous systems on earth, research on the ISS is essential, and Ekoplasma will follow in a line of successful preceding experiments aboard the ...

In humankind’s endeavor to explore beyond our planet and travel further into space, we are now at the threshold of an era in which it is possible to move to and from low Earth orbit (LEO) with increasing ease and reduced cost. Through the International Space Station (ISS) U.S. National Laboratory, investigators from industry, academia, and government can easily access the unique LEO environment on the ISS to conduct research and development (R&D) activities in ways not possible on Earth. A key advantage of the LEO environment for life sciences research is the ability to conduct experiments in sustained microgravity conditions. The ability to conduct long-term research in microgravity enables opportunities for novel, fundamental studies in tissue engineering and regenerative medicine, including research on stem cell proliferation and differentiation, biofabrication, and disease modeling using microphysiological systems (MPS) that build on prior research using simulated microgravity c...

Recent studies have analyzed the chance of exploiting Global Navigation Satellite Systems (GNSS)-Reflectometry observables for maritime surveillance and sea target detection. In this paper, we provide a feasibility study of the ship detection problem using spaceborne GNSS-R data. The analysis is performed via the evaluation of the signal-to-noiseplus-clutter-ratio and signal-to-noise-ratio relevant to an isolated ship target in open sea. In particular, we investigated the impact of the GNSS-R acquisition geometry and radar signal polarization. The influence of sea state and ship orientation is assessed as well. The analysis is based on a sound theoretical electromagnetic model of the bistatic radar cross section of the ship target. The analysis clearly shows the benefits of 1) the backscattering configuration with respect to the conventional forward-scattering one and 2) the RHCP receiving channel w.r.t. the conventional LHCP one, used in sea surface analysis. However, the ship orientation and the sea state still play a key role in ship detectability.

An Electronic Nose is being developed at JPL and Caltech for use in environmental monitoring in the International Space Station. The Electronic Nose (ENose) is an array of 32 polymer film cmnductometric sensors; the pattern of response may be deconvoluted to identify contaminants in the environment. An engineering test model of the ENose was used to monitor the air of the Early Human Test experiment at Johnson Space Center for 49 days. Examination of the data recorded by the ENose shows that major excursions in the resistance recorded in the sensor array may be correlated with events recorded in the Test Logs of the Test Chamber.

This work describes the thermal characterization on ground and under a varying gravity field (parabolic flights) of a large diameter Pulsating Heat Pipe (PHP) especially designed for its future implementation on the heat transfer host module of the International Space Station (ISS) for long term microgravity experiments. A multi-turn compact closed loop PHP is made of aluminum and partially filled with FC-72 (50% vol.). The 3mm tube internal diameter is larger than the static capillary limit evaluated on ground conditions for the above working fluid, with the objective of dissipating larger heat power inputs compared to smaller diameter channels, under microgravity conditions, allowing the typical slug flow pattern of PHPs to occur. To provide a detailed insight on the thermo-hydraulics phenomena during the device start-up under the occurrence of microgravity, the PHP is equipped with a transparent sapphire tube insert, two miniature pressure transducers and two microthermocouples. ...

One of the main challenges to be faced in deep space missions is to protect the health and ensure the maximum efficiency of the crew by preparing methods of prevention and in situ diagnosis. Indeed, the hostile environment causes important health problems, ranging from muscle atrophy, osteopenia, and immunological and metabolic alterations due to microgravity, to an increased risk of cancer caused by exposure to radiation. It is, therefore, necessary to provide new methods for the real-time measurement of biomarkers suitable for deepening our knowledge of the effects of space flight on the balance of the immune system and for allowing the monitoring of the astronaut's health during long-term missions. APHRODITE will enable human space exploration because it fills this void that affects both missions in LEO and future missions to the Moon and Mars. Its scientific objectives are the design, production, testing, and in-orbit demonstration of a compact, reusable, and reconfigurable system for performing the real-time analysis of oral fluid samples in manned space missions. In the frame of this project, a crew member onboard the ISS will employ APHRODITE to measure the selected target analytes, cortisol, and dehydroepiandrosterone sulfate (DHEA-S), in oral fluid, in four (plus one additional desired session) separate experiment sessions. The paper addresses the design of the main subsystems of the analytical device and the preliminary results obtained during the first implementations of the device subsystems and testing measurements on Earth. In particular, the system design and the experiment data output of the lab-on-chip photosensors and of the front-end readout electronics are reported in detail along with preliminary chemical tests for

In March 1991 tbe CRRES spacecraft measured a new transient radiation belt resulting from a solar proton event and subsequent geomagnetic disturbance. The presence of this belt was also noted by dosimeter-radiometers aboard the Mir space station (approx. 400 km, 5 lo orbit) and by particle telescopes on the NOAA-10 spacecraft (850 km, 98'). This event provides a unique opportunity to compare particle flux and dose measurements made by different instruments in different orbits under changing conditions. We present here a comparison of the measurements made by the different detectors. We discuss the topology and dynamics of the transient radiation belt over a period of more than one year.

Uncertainties and correlations are propagated in absolute spectral irradiance scale, where a modified Planck's radiation law is fitted to filter radiometer (FR) data. The lack-of-fit error component is included in the uncertainty analysis with the purpose of finding an optimal degree for the polynomial describing the effective emissivity of quartz-tungsten halogen lamps.

The DLR Earth Sensing Imaging Spectrometer (DESIS) is a new space-based hyperspectral instrument developed by DLR and operated under collaboration between the German Aerospace Center (DLR) and Teledyne Brown Engineering (TBE). DESIS will be mounted on the International Space Station on the MUSES platform in 2018 and will provide hyperspectral Earth Observation in the wavelength range from visible to near-infrared with high resolution and near global coverage. TBE provides the platform and infrastructure on the ISS. DLR developed the instrument, while the optical system was fabricated and pre-aligned by the Fraunhofer Institut für Angewandte Optik und Feinmechanik (IOF). This paper presents the on-ground adjustment, focusing and calibration approach for DESIS done at the optical lab of the Institut für Optische Sensorsysteme (DLR). The optical lab set-up will be described in detail. Selected calibration results like detector Modulation Transfer Function (MTF) and linearity, optics MTF and wave front, focus position, smile and keystone measurement, instrument spatial and spectral MTF, and absolute radiometric calibration will be presented. The spectral and radiometric in-flight calibration approach of the DESIS calibration unit (CAL) based on stabilized Light Emitting Diode (LED) arrays will be demonstrated. In addition, the innovative pointing unit (POI) in front of the instrument and its pointing accuracy will be introduced. Finally imaging quality and accuracy of the sensor calibration will be evaluated with respect to foreseen applications.

This paper presents the design of an advanced kinematic and kinetic measurement system for the International Space Station (ISS). Massachusetts Institute of Technology (MIT), NASA, Politecnico di Milano University, and the Italian Space Agency are currently developing jointly an integrated system capable of precisely measuring the forces and moments the astronauts induce and their postures and movements. Kinetic measurements will be performed with special crew restraint and mobility aids instrumented with strain gages. The compact electronics component of the sensors provides real-time feedback of the load level applied. The kinematic measurements of astronaut motion will be accomplished with ELITE-S2, a general purpose opto-electronic motion analysis system proposed for the ISS by the Italian Space Agency (Agenzia Spaziale Italiana, ASI) with the support of the French Space Agency (Centre National d'Etudes Spatiales, CNES). This versatile motion capture system provides three-dimensional (3-D) kinematics data in real-time using video-image processing for detecting multiple passive markers.

Previous studies examining GPS relative navigation for spacecraft performing rendezvous with the International Space Station (ISS) have not accounted for degradation in GPS navigation performance due to multipath or blockage of GPS signals by the ISS. This study analyzes these effects on GPS navigation in the vicinity of the ISS. A simulation of a spacecraft GPS receiver operating near the ISS has been developed. This simulation includes orbit models for the GPS constellation, the ISS, and the spacecraft, as well as models for GPS signal blockage and multipath. The blockage simulation shows that aiding of GPS is required when the spacecraft approaches within 60 m of the ISS. The multipath simulation shows the expected trends in range errors as a function of GPS satellite elevation angle, distance from the ISS, number of multipath rays, and the radar cross-sectional area of the ISS.

The Low Earth Orbit (LEO) experiment Biology and Mars Experiment (BIOMEX) is an interdisciplinary and international space research project selected by ESA. The experiment will be accommodated on the space exposure facility EXPOSE-R2 on the International Space Station (ISS) and is foreseen to be launched in 2013. The prime objective of BIOMEX is to measure to what extent biomolecules, such as pigments and cellular components, are resistant to and able to maintain their stability under space and Mars-like conditions. The results of BIOMEX will be relevant for space proven biosignature definition and for building a biosignature data base (e.g. the proposed creation of an international Raman library). The library will be highly relevant for future space missions such as the search for life on Mars. The secondary scientific objective is to analyze to what extent terrestrial extremophiles are able to survive in space and to determine which interactions between biological samples and selected minerals (including terrestrial, Moon-and Mars analogs) can be observed under space and Mars-like conditions. In this context, the Moon will be an additional platform for performing similar experiments with negligible magnetic shielding and higher solar and galactic irradiation compared to LEO. Using the Contents lists available at SciVerse ScienceDirect

Project Irazú was an innovative space mission that aimed to propel the advancement of the aerospace sector in Costa Rica, by developing a ground to space communication solution for daily monitoring of carbon fixation in forests and tree plantations. Irazú is Central America's first satellite mission and is a joint endeavor between the Central American Association of Aeronautics and Space and the Costa Rica Institute of Technology, along with national and international partners. The 1U CubeSat developed in this project was deployed from the International Space Station on May 2018, commencing straightaway operations. The scientific mission demonstrated a practical novel solution to monitor daily tree growth by using wireless electronic sensors and a store and forward satellite link. This article presents an overview of the project, along with the mission architecture, summary of the Assembly, Integration and Testing (AI&T) and operations phases, and results from the scientific mission, including the sensor's performance and measurements of the daily estimated tree diameter during six months. The impacts that the project had on an emerging space nation such as Costa Rica is included as well.

Many simulated micro-gravity (micro-G) experiments on earth suggest that micro-G conditions are not compatible with early mammalian embryo development. Recently, the first two “space embryo” studies have been published showing that early mouse embryo development can occur in real microgravity (real micro-G) conditions in orbit. In the first of these studies, published in 2020, Lei and collaborators developed automated mini-incubator (AMI) devices for mouse embryos facilitating cultivation, microscopic observation, and fixation1. Within these AMI apparatuses, 3400 non-frozen 2-cell embryos were launched in a recoverable satellite, experiencing sustained microgravity (~0.001G) for 64 h post-orbit before fixation in space and recovery on earth. In a subsequent study, in 2023, Wakayama and colleagues2 devised Embryo Thawing and Culturing (ETC) devices, enabling manual thawing, cultivation, and fixation of frozen 2-cell mouse embryos by a trained astronaut aboard the International Space Station (ISS). Within the ETCs, a total of 720 2-cell mouse embryos underwent thawing and cultivation for 4 days on the ISS, subject to either microgravity (n ¼ 360) and simulated-1G (n ¼ 360) conditions. The  summary findings from both space embryo experiments indicate that mouse embryos can progress through embryogenesis from the 2-cell stage to the blastocyst stage under real micro-G conditions with few defects. Collectively, these studies propose the potential for mammalian reproduction under real micro-G conditions, challenging earlier simulated micro-G research suggesting otherwise.

The Alpha Magnetic Spectrometer (AMS) experiment to be installed on the International Space Station (ISS) will be equipped with a proximity focusing Ring Imaging Cherenkov (RICH) detector for measuring the electric charge and velocity of the charged cosmic particles. A RICH prototype consisting of 96 photomultiplier units, including a piece of the conical reflector, was built and its performance evaluated with ion beam data. Preliminary results of the in-beam tests performed with ion fragments resulting from collisions of a 158 GeV/c/nuc primary beam of Indium ions (CERN SPS) on a Pb target are reported. The collected data included tests to the final front-end electronics and to different aerogel radiators. Cherenkov rings for a large range of charged nuclei and with reflected photons were observed. The data analysis confirms the design goals. Charge separation up to Fe and velocity resolution of the order of 0.1% for singly charged particles are obtained.

The AMS detector, to be installed on the International Space Station, includes a Ring Imaging Cerenkov detector with two different radiators, silica aerogel (n=1.05) and sodium fluoride (n=1.334). This detector is designed to provide very precise measurements of velocity and electric charge in a wide range of cosmic nuclei energies and atomic numbers. The detector geometry, in particular the presence of a reflector for acceptance purposes, leads to complex Cerenkov patterns detected in a pixelized photomultiplier matrix. The results of different reconstruction methods applied to test beam data as well as to simulated samples are presented. The velocity and charge measurements provided by the RICH detector endow the AMS spectrometer with precise particle identification capabilities in a wide energy range. The expected performances on light isotope separation are discussed. To ensure nominal performances throughout the flight, several detector parameters have to be carefully monitored...

The Alpha Magnetic Spectrometer (AMS-02) is a high energy particle physics experiment that will study cosmic rays in the ∼ 100 MeV to 1 TeV range and will be installed on the International Space Station (ISS) for at least 3 years. A first version of AMS-02, AMS-01, flew aboard the space shuttle Discovery from June 2 to June 12, 1998, and collected 10 8 cosmic ray triggers. Part of the Mir space station was within the AMS-01 field of view during the four day Mir docking phase of this flight. We have reconstructed an image of this part of the Mir space station using secondary π − and µ − emissions from primary cosmic rays interacting with Mir. This is the first time this reconstruction was performed in AMS-01, and it is important for understanding potential backgrounds during the 3 year AMS-02 mission.

The Cosmic Ray Energetics And Mass (CREAM) instrument is configured with a suite of particle detectors to measure TeV cosmic-ray elemental spectra from protons to iron nuclei over a wide energy range. The goal is to extend direct measurements of cosmic-ray composition to the highest energies practical, and thereby have enough overlap with ground based indirect measurements to answer questions on cosmic-ray origin, acceleration and propagation. The balloon-borne CREAM was flown successfully for about 161 days in six flights over Antarctica to measure elemental spectra of Z = 1-26 nuclei over the energy range 10 10 to >10 14 eV. Transforming the balloon instrument into ISS-CREAM involves identification and replacement of components that would be at risk in the International Space Station (ISS) environment, in addition to assessing safety and mission assurance concerns. The transformation process includes rigorous testing of components to reduce risks and increase survivability on the launch vehicle and operations on the ISS without negatively impacting the heritage of the successful CREAM design. The project status, including results from the ongoing analysis of existing data and, particularly, plans to increase the exposure factor by another order of magnitude utilizing the International Space Station are presented.

Carbonaceous chondrites (groups CO and CV) contain three types of ferromagnesian chondrules that can be distinguished on the basis of mineralogy and texture. Statistical analysis of the bulk chemical compositions of these chondrule types suggests that two of the three types are genetically related. The chondrules in carbonaceous chondrites can thus be separated into two populations. These populations are also apparently distinct in terms of redox state and oxygen isotopic composition. The more abundant population (I) is clearly different from chondrules in unequilibrated ordinary chondrites, but the minor population (II) is similar to them in many respects. These chondrule populations may have formed by melting of solid, locally homogeneous precursor materials in different regions of the nebula, and were mixed after solidification was complete.

Space Radiation/EVA/LEO/ISS/Radiation Safety/Modeling. Ongoing assembly and maintenance activities at the International Space Station (ISS) require much more extravehicular activity (EVA) than did the earlier U.S. Space Shuttle missions. It is thus desirable to determine and analyze, and possibly foresee, as accurately as possible what radiation exposures crew members involved in EVAs will experience in order to minimize risks and to establish exposure limits that must not to be exceeded. A detailed CAD model of the U.S. Space Shuttle EVA Spacesuit, developed at NASA Langley Research Center (LaRC), is used to represent the directional shielding of an astronaut; it has detailed helmet and backpack structures, hard upper torso, and multilayer space suit fabric material. The NASA Computerized Anatomical Male and Female (CAM and CAF) models are used in conjunction with the space suit CAD model for dose evaluation within the human body. The particle environments are taken from the orbit-averaged NASA AP8 and AE8 models at solar cycle maxima and minima. The transport of energetic particles through space suit materials and body tissue is calculated by using the NASA LaRC HZETRN code for hadrons and a recently developed deterministic transport code, ELTRN, for electrons. The doses within the CAM and CAF models are determined from energy deposition at given target points along 968 directional rays convergent on the points and are evaluated for several points on the skin and within the body. Dosimetric quantities include contributions from primary protons, light ions, and electrons, as well as from secondary brehmsstrahlung and target fragments. Directional dose patterns are displayed as rays and on spherical surfaces by the use of a color relative intensity representation.

Neutron production cross sections have been measured from 290 MeV/nucleon C and 600 MeV/nucleon Ne interacting in a slab of simulated Martian regolith/polyethylene composite, and from 400 MeV/nucleon Ne interacting in a section of wall materials from the International Space Station. Neutron spectra were measured at 7 angles between 5º and 80º, and for neutron energies 5 MeV and greater. Spectra at forward angles are dominated by the breakup of the projectile, whereas spectra at back angles show the typical exponential falloff with energy that is indicative of decay from the overlap region and the target remnant. The measured total neutron production cross sections indicate that the regolith/polyethylene composite may be a more effective shielding material than the ISS wall materials, in terms of the number of neutrons produced.