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NASA NTRS2017

Status of the Redesign of the Extravehicular Mobility Unit Airlock Cooling Loop Recovery Assembly

During EVA (Extravehicular Activity) 23 aboard the ISS (International Space Station) on 07/16/2013 an episode of water in the EMU (Extravehicular Mobility Unit) helmet occurred, necessitating a termination of the EVA (Extravehicular Activity) shortly after it began. The root cause of the failure was determined to be ground-processing short-comings of the ALCLR Ion Beds which led to various levels of contaminants being introduced into the Ion Beds before they left the ground. The Ion Beds were thereafter used to perform on-orbit routine scrubbing operations for the EMU cooling water loop which led to the failure. The root cause investigation identified several areas for improvement of the ALCLR Assembly which have since been initiated. Enhanced washing techniques for the ALCLR Ion Bed have been developed and implemented. On-orbit cooling water conductivity and pH analysis capability to allow the astronauts to monitor proper operation of the ALCLR Ion Bed during scrubbing operation have been investigated and are being incorporated. A simplified means to acquire on-orbit EMU cooling water samples has been designed as well. Finally, an inherently cleaner organic adsorbent to replace the current lignite-based activated carbon, and a non-separable replacement for the separable mixed ion exchange resin have been selected. These efforts are being undertaken to enhance the performance and reduce the risk associated with operations to ensure the long-term health of the EMU cooling water circuit. The intent of this paper is to provide an update of the effort to re-design the ALCLR (Airlock Cooling Loop Recovery) hardware. Last year, this effort was in the early stages of concept development and test which was reported in ICES Paper ICES-2016-221. Those phases are now complete and the final outcomes, as well as plans to build and field the hardware, are being reported on.

Steele, John↗

NASA NTRS2019

A New Class of Changing-look LINERs

We report the discovery of six active galactic nuclei (AGNs) caught "turning on" during the first nine months of the Zwicky Transient Facility (ZTF) survey. The host galaxies were classified as low-ionization nuclear emission-line region galaxies (LINERs) by weak narrow forbidden line emission in their archival SDSS spectra, and detected by ZTF as nuclear transients. In five of the cases, we found via follow-up spectroscopy that they had transformed into broad-line AGNs, reminiscent of the changing-look LINER iPTF16bco. In one case, ZTF18aajupnt/AT2018dyk, follow-up Hubble Space Telescope ultraviolet and ground-based optical spectra revealed the transformation into a narrow-line Seyfert 1 with strong [Fe vii, x, xiv] and He ii λ 4686 coronal lines. Swift monitoring observations of this source reveal bright UV emission that tracks the optical flare, accompanied by a luminous soft X-ray flare that peaks ~60 days later. Spitzer follow-up observations also detect a luminous mid-infrared flare, implying a large covering fraction of dust. Archival light curves of the entire sample from CRTS, ATLAS, and ASAS-SN constrain the onset of the optical nuclear flaring from a prolonged quiescent state. Here we present the systematic selection and follow-up of this new class of changing-look LINERs, compare their properties to previously reported changing-look Seyfert galaxies, and conclude that they are a unique class of transients well-suited to test the uncertain physical processes associated with the LINER accretion state.

Sara Frederick↗

NASA NTRS1985

Polyamine levels as related to growth, differentiation and senescence in protoplast-derived cultures of Vigna aconitifolia and Avena sativa

We have previously reported that aseptically cultured mesophyll protoplasts of Vigna divide rapidly and regenerate into complete plants, while mesophyll protoplasts of Avena divide only sporadically and senesce rapidly after isolation. We measured polyamine titers in such cultures of Vigna and Avena, to study possible correlations between polyamines and cellular behavior. We also deliberately altered polyamine titer by the use of selective inhibitors of polyamine biosynthesis, noting the effects on internal polyamine titer, cell division activity and regenerative events. In Vigna cultures, levels of free and bound putrescine and spermidine increased dramatically as cell division and differentiation progressed. The increase in bound polyamines was largest in embryoid-forming callus tissue while free polyamine titer was highest in root-forming callus. In Avena cultures, the levels of total polyamines decreased as the protoplast senesced. The presence of the inhibitors alpha-difluoromethyl-arginine (specific inhibitor of arginine decarboxylase), alpha-difluoromethylornithine (specific inhibitor of ornithine decarboxylase) and dicyclohexylamine (inhibitor of spermidine synthase) reduced cell division and organogenesis in Vigna cultures. Addition of low concentration of polyamines to such cultures containing inhibitors or removal of inhibitors from the culture medium restored the progress of growth and differentiation with concomitant increase in polyamine levels.

NASA Program Space Biology↗

NASA NTRS1962

Collected Papers on Instability of Shell Structures - 1962

Shell structures are important components of airplanes, missiles, and space vehicles, but present capabilities for predicting the local and general instability of many such structures are inadequate. A large effort continues to be devoted to the stability analysis of shell structures, and considerable progress has been made. Results are slowly disseminated, however, and many engaged in research are not fully cognizant of the problems and practices of the vehicle designers who utilize research results. Therefore, an NASA SYMPOSIUM ON INSTABILITY OF SKELL STRUCTURES was organized by the Langley Research Center with sessions held there on October 24 and 25, 1962. Participants were limited to persons contributing papers and to certain officials of the U.S. Government. This symposium was planned to provide those persons concerned with shell instability at research laboratories, at educational institutions, and in the aerospace industry with a comprehensive view of the present state of the art, including the voids in present knowledge, important current problems, and the most fruitful directions for future theoretical and experimental research on the instability of all types of shell structures. Individuals actively engaged in research on shell stability or design were invited to contribute written papers for inclusion in a compilation to be distributed to the participants prior to the symposium. A few papers were selected by a steering committee for oral presentation at the symposium. Provision was made, also, for a discussion of all papers.

MISSILE↗

NASA NTRS1990

Procedures for minimizing the effects of high solar activity on satellite tracking and ephemeris generation

We are currently experiencing a period of high solar radiation combined with wide short-term fluctuations in the radiation. The short-term fluctuations, especially when combined with highly energetic solar flares, can adversely affect the mission of U.S. Space Command's Space Surveillance Center (SSC) which catalogs and tracks the satellites in orbit around the Earth. Rapidly increasing levels of solar electromagnetic and/or particle radiation (solar wind) causes atmospheric warming, which, in turn, causes the upper-most portions of the atmosphere to expand outward, into the regime of low altitude satellites. The increased drag on satellites from this expansion can cause large, unmodeled, in-track displacements, thus undermining the SSC's ability to track and predict satellite position. On 13 March 1989, high solar radiation levels, combined with a high-energy solar flare, caused an exceptional amount of short-term atmospheric warming. The SSC temporarily lost track of over 1300 low altitude satellites--nearly half of the low altitude satellite population. Observational data on satellites that became lost during the days following the 13 March 'solar event' was analyzed and compared with the satellites' last element set prior to the event (referred to as a geomagnetic storm because of the large increase in magnetic flux in the upper atmosphere). The analysis led to a set of procedures for reducing the impact of future geomagnetic storms. These procedures adjust selected software limit parameters in the differential correction of element sets and in the observation association process and must be manually initiated at the onset of a geomagnetic storm. Sensor tasking procedures must be adjusted to ensure that a minimum of four observations per day are received for low altitude satellites. These procedures have been implemented and, thus far, appear to be successful in minimizing the effect of subsequent geomagnetic storms on satellite tracking and ephemeris computation.

Bredvik, Gordon D.↗

NASA NTRS1987

Thermal dependence of neural activity in the hamster hippocampal slice preparation

1. Neural activity was recorded in an in vitro hamster hippocampal slice preparation while the temperature of the Ringer's solution bathing in the slice was controlled at selected levels. 2. The amplitude of the population spike (action potentials from a group of pyramidal cells) was measured as bath temperature was lowered from 35 degrees C to temperatures where a response could not be evoked. 3. Plots of population spike amplitude versus temperature have bell-shaped curves. The population spikes increased in amplitude as temperature was lowered from 35 degrees C, reached a peak amplitude between 25 and 20 degrees C, and then decreased until a response could not be evoked when temperature was further lowered. 4. These in vitro results obtained in the slice preparation are related to in vivo hippocampal studies. Results are interpreted as consistent with the proposal reviewed here that neural activity in the hippocampus plays a role at specific stages of entrance into and arousal from hibernation.

Non-NASA Center↗

NASA NTRSDate not supplied

Testing the Exploration ConOps (ExCon) Mockup Suit in Lunar Analog Environments in 2022

Understanding how to effectively train for Extravehicular Activities (EVAs) for Artemis missions is critical. Developing high-fidelity simulation environments is important for Artemis mission preparation. Because the actual Lunar exploration environment cannot be fully replicated on Earth, it is paramount to determine where and how to properly train the Artemis team. The overall focus for this test series was developing the capability to perform Artemis simulated EVAs in high-fidelity, full-scale environments. This test series was broken into three distinct tests titled after the EVA & Human Surface Mobility (HSM) Program (EHP) integrated test team: Joint EVA & HSM Test Team (JETT). The test locations are planned to serve as Artemis training sites and were selected because of their relevance to the expected Artemis Lunar terrain. JETT1 was conducted near Kilbourne Hole by El Paso, Texas and focused on hardware development and checkout. JETT2 was conducted in the Icelandic Highlands and began the transition towards EVA concept of operations (con-ops), risks and technology. JETT3 was conducted near SP Crater by Flagstaff, Arizona and focused on simulating the Artemis III mission including a Houston based Flight Control Team (FCT) and a Science Mission Directorate (SMD) science team. All three JETT tests utilized the Exploration Concept of Operations (ExCon) mockup space suit. The ExCon mockup suit is a lightweight, unpressurized Exploration Extravehicular Mobility Unit (xEMU) simulator. While it cannot replicate the feel of working within a pressurized suit, it does introduce similar volume constraints and some of the mobility programing to simulate the user experience in the xEMU. Overall, the JETT testing was able to create a simulated Lunar EVA and have two subjects perform full scale operations in line with Artemis III mission expectations. Future work is planned to continue to improve the simulation quality of Lunar EVA simulations.

spacesuit↗

NASA NTRSDate not supplied

Testing the Exploration Conops (Excon) Mockup Suit in Lunar Analog Environments in 2022

spacesuit↗

NASA NTRS2008

Laser Sounder for Measuring Atmospheric CO2 Concentrations: Progress Toward Ascends

The next generation of space-based, active remote sensing instruments for measurement of tropospheric CO2 promises a capability to quantify global carbon sources and sinks at regional scales. Active (laser) methods will extend CO2 measurement coverage in time, space, and perhaps precision such that the underlying mechanisms for carbon exchange at the surface can be understood with .sufficient detail to confidently project the future of carbon-climate interaction and the influence of remediative policy actions. The recent Decadal Survey for Earth Science by the US National Research Council has recommended such a mission called the Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) for launch in 2013-2016. We have been developing a laser technique for measurement of tropospheric CO2 for a number of years. Our immediate goal is to develop and demonstrate the method and instrument technology that will permit measurements of the CO2 column abundance over a horizontal path and from aircraft at the few-ppmv level. Our longer-term goal is to demonstrate the required capabilities of the technique, develop a space mission approach, and design the instrument for an ASCENDS-type mission. Our approach is to use a dual channel laser absorption spectrometer (i.e., differential absorption in altimeter mode), which continuously measures from a near-polar circular orbit. We use several co-aligned tunable fiber laser transmitters allowing simultaneous measurement of the absorption from a CO2 line in the 1570 nm band, O2 extinction in the oxygen A-band (near 765 nm), and aerosol backscatter in the same measurement path. We measure the energy of the laser echoes at nadir reflected from land and water surfaces, day and night. The lasers have spectral widths much narrower than the gas absorption lines and are turned on and off the selected CO2 and O2 lines at kHz rates. The gas extinction and column densities for the CO2 and O2 gases are estimated from the ratio of the on and off-line singnals via the DIAL technique. We used pulsed laser signals, photon counting detectors, and time gating to isolate the laser returns from the surface, and to reject photons scattered from thin clouds and aerosols. High signal-to-noise ratios are required and the CO2 estimates can be sensitive to small drifts or other errors in the instrument, so the absorption estimates need to be quite stable for hours. We have constructed a breadboard version of the CO2 sensor that uses a low power fiber laser and a 20 cm diameter telescope. We have used it to make measurements of CO2 absorption in the laboratory and over 200-m to 2-km long open horizontal paths. These have been done in several sessions extending over multiple days, which allows us to assess the measurement stability and to compare absorption variations to readings from an external in situ CO2 sensor. We have also calculated characteristics of the technique for space including its expected measurement performance for different modulation types, and have performed an initial space mission accommodation study. We sill describe these results in the presentation.

Abshire, J. B.↗

NASA NTRS2017

Cardiovascular Disease Risk in NASA Astronauts Across the Lifespan: Historical Cohort Studies

Acute effects of spaceflight on the cardiovascular system have been studied extensively, but the combined chronic effects of spaceflight and aging are not well understood. Preparation for and participation in space flight activities are potentially associated with cardiovascular disease risk factors (e.g., altered dietary and exercise habits, physical and emotional stress, circadian shifts, radiation). Further, astronauts who travel into space multiple times may be at an increased risk across their lifespan. However, comparing the risk of cardiovascular disease in astronauts to other large cohorts is difficult. For example, comparisons between astronauts and large national cohorts, such as the National Health and Nutrition Examination Survey and the National Health Information Survey, are hampered by significant differences in health status between astronauts and the general population, and most of these national studies fail to provide longitudinal data on population health. To address those limitations, NASA's Longitudinal Study of Astronaut Health previously sought to compare the astronauts to a cohort of civil servants employed at the Johnson Space Center. However, differences between the astronauts and civil servants at the beginning of the study, as well as differential follow up, limited the ability to interpret the results. To resolve some of these limitations, two unique cohorts of healthy workers, U.S. Air Force aviators and Cooper Center Longitudinal Study participants, have been identified as potential comparison populations for the astronaut corps. The Air Force cohort was chosen due to similarities in health at selection, screening, and some occupational exposures that Air Force aviators endure, many of which mirror that of the astronaut corps. The Cooper Clinic cohort, a generally healthy prevention cohort, was chosen for the vast array of clinical cardiovascular measures collected in a longitudinal manner complementary to those collected on astronauts, for a large number of subjects since 1971. The purpose of this study is to understand the incidence of cardiovascular disease outcomes and risk factors in the astronaut corps and determine whether the rates of disease are different than these two cohorts. The research questions are: 1. Are there differences in the incidence of CVD outcomes (MI, revascularization, and stroke) between each cohort and the NASA Astronaut cohort? 2. Are there differences in the incidence of CVD risks (hypertension, hyperlipidemia, arrhythmias, and diabetes) between each cohort and the NASA Astronaut cohort? 3. Are there differences between each cohort and the NASA Astronaut cohort in how CVD risk factors (e.g., lipids, behaviors) change across time? Collectively, results from these studies will enhance our understanding of how cardiovascular disease outcomes and risk factors change across time in astronauts compared to other longitudinally-studied healthy cohorts and determine if there are interactions between or additive effects of the occupational health effects of spaceflight exposure and normal aging.

Charvat, Jacqueline M.↗

NASA NTRS2014

CEO Sites Mission Management System (SMMS)

Late in fiscal year 2011, the Crew Earth Observations (CEO) team was tasked to upgrade its science site database management tool, which at the time was integrated with the Automated Mission Planning System (AMPS) originally developed for Earth Observations mission planning in the 1980s. Although AMPS had been adapted and was reliably used by CEO for International Space Station (ISS) payload operations support, the database structure was dated, and the compiler required for modifications would not be supported in the Windows 7 64-bit operating system scheduled for implementation the following year. The Sites Mission Management System (SMMS) is now the tool used by CEO to manage a heritage Structured Query Language (SQL) database of more than 2,000 records for Earth science sites. SMMS is a carefully designed and crafted in-house software package with complete and detailed help files available for the user and meticulous internal documentation for future modifications. It was delivered in February 2012 for test and evaluation. Following acceptance, it was implemented for CEO mission operations support in April 2012. The database spans the period from the earliest systematic requests for astronaut photography during the shuttle era to current ISS mission support of the CEO science payload. Besides logging basic image information (site names, locations, broad application categories, and mission requests), the upgraded database management tool now tracks dates of creation, modification, and activation; imagery acquired in response to requests; the status and location of ancillary site information; and affiliations with studies, their sponsors, and collaborators. SMMS was designed to facilitate overall mission planning in terms of site selection and activation and provide the necessary site parameters for the Satellite Tool Kit (STK) Integrated Message Production List Editor (SIMPLE), which is used by CEO operations to perform daily ISS mission planning. The CEO team uses the SMMS for three general functions - database queries of content and status, individual site creation and updates, and mission planning. The CEO administrator of the science site database is able to create or modify the content of sites and activate or deactivate them based on the requirements of the sponsors. The administrator supports and implements ISS mission planning by assembling, reporting, and activating mission-specific site selections for management; deactivating sites as requirements are met; and creating new sites, such as International Charter sites for disasters, as circumstances warrant. In addition to the above CEO internal uses, when site planning for a specific ISS mission is complete and approved, the SMMS can produce and export those essential site database elements for the mission into XML format for use by onboard Earth-location systems, such as Worldmap. The design, development, and implementation of the SMMS resulted in a superior database management system for CEO science sites by focusing on the functions and applications of the database alone instead of integrating the database with the multipurpose configuration of the AMPS. Unlike the AMPS, it can function and be modified within the existing Windows 7 environment. The functions and applications of the SMMS were expanded to accommodate more database elements, report products, and a streamlined interface for data entry and review. A particularly elegant enhancement in data entry was the integration of the Google Earth application for the visual display and definition of site coordinates for site areas defined by multiple coordinates. Transfer between the SMMS and Google Earth is accomplished with a Keyhole Markup Language (KML) expression of geographic data (see figures 3 and 4). Site coordinates may be entered into the SMMS panel directly for display in Google Earth, or the coordinates may be defined on the Google Earth display as a mouse-controlled polygonal definition and transferred back into the SMMS as KML input. This significantly reduces the possibility of errors in coordinate entries and provides visualization of the scale of the site being defined. CEO now has a powerful tool for managing and defining sites on the Earth's surface for both targets of astronaut photography or other onboard remote sensing systems. It can also record and track results by sponsor, collaborator, or type of study.

Trenchard, Mike↗

NASA NTRS2011

Risk Balance: A Key Tool for Mission Operations Assurance

The Mission Operations Assurance (MOA) discipline actively participates as a project member to achieve their common objective of full mission success while also providing an independent risk assessment to the Project Manager and Office of Safety and Mission Success staff. The cornerstone element of MOA is the independent assessment of the risks the project faces in executing its mission. Especially as the project approaches critical mission events, it becomes imperative to clearly identify and assess the risks the project faces. Quite often there are competing options for the project to select from in deciding how to execute the event. An example includes choices between proven but aging hardware components and unused but unproven components. Timing of the event with respect to visual or telecommunications visibility can be a consideration in the case of Earth reentry or hazardous maneuver events. It is in such situations that MOA is called upon for a risk balance assessment or risk trade study to support their recommendation to the Project Manager for a specific option to select. In the following paragraphs we consider two such assessments, one for the Stardust capsule Earth return and the other for the choice of telecommunications system configuration for the EPOXI flyby of the comet Hartley 2. We discuss the development of the trade space for each project's scenario and characterize the risks of each possible option. The risk characterization we consider includes a determination of the severity or consequence of each risk if realized and the likelihood of its occurrence. We then examine the assessment process to arrive at a MOA recommendation. Finally we review each flight project's decision process and the outcome of their decisions.

operations↗

NASA NTRSDate not supplied

NASA’s Human Landing System: Enabling the Next Generation of Lunar Science

The Human Landing System (HLS) is the mode of transportation that will take astronauts to the lunar surface as part of NASA's Artemis exploration program. HLS also serves as a research platform both on the surface and in lunar orbit, enabling critical scientific investigations on and of the Moon. With support at NASA centers around the country, the HLS program, based at Marshall Space Flight Center in Huntsville, Alabama, is working closely with its commercial partners throughout the development process to design and build innovative and technically advanced lunar landers – new vehicles designed for the modern era of space travel – leveraging decades of human spaceflight experience and the speed of the commercial sector. In 2019, NASA asked U.S. industry for proposals to design and develop a human lander for the first human mission to the lunar surface under Artemis. Initial contracts were awarded to Blue Origin Federation, Dynetics, and SpaceX to advance their designs. Following the execution of the ten-month Base Period, NASA announced in April 2021 that the agency selected SpaceX to move forward with its human landing system [1] and land the first two astronauts on the lunar surface during the Artemis III mission. Following two protest periods, NASA awarded the contract, known as Option A, to SpaceX in July 2021 and resumed work in November 2021 (Fig. 1). In parallel, the HLS program has been preparing for the acquisition that will procure regular crewed transportation to the lunar surface following Artemis III. NASA released a request for information (RFI) in July 2021 asking U.S. industry for feedback to help inform the future solicitation, known as Lunar Exploration Transportation Services (LETS) [2]. Also in July 2021, NASA released the NextSTEP-2 Appendix N broad agency announcement soliciting new work from U.S. industry to mature their HLS designs and perform risk reduction activities in advance of the LETS procurement [3]. NASA selected Blue Origin Federation, Dynetics, Lockheed Martin, Northrop Grumman, and SpaceX to participate [4]. This work will also help better inform the LETS procurement and prepare industry to propose. NASA hopes to release a draft request for proposals (RFP) in Spring 2022.

R C Weber↗

NASA NTRS2007

Hubble 2006: Science Year in Review

The 10 science articles selected for this years annual science report exemplify the range of Hubble research from the Solar System, across our Milky Way, and on to distant galaxies. The objects of study include a new feature on Jupiter, binaries in the Kuiper Belt, Cepheid variable stars, the Orion Nebula, distant transiting planets, lensing galaxies, active galactic nuclei, red-and-dead galaxies, and galactic outflows and jets. Each narrative strives to construct the readers understanding of the topics and issues, and to place the latest research in historical, as well as scientific, context. These essays reveal trends in the practice of astronomy. More powerful computers are permitting astronomers to study ever larger data sets, enabling the discovery of subtle effects and rare objects. (Two investigations created mosaic images that are among the largest produced to date.) Multiwavelength data sets from ground-based telescopes, as well as other great observatories Spitzer and Chandraare increasingly important for holistic interpretations of Hubble results. This yearbook also presents profiles of 12 individuals who work with Hubble, or Hubble data, on a daily basis. They are representative of the many students, scientists, engineers, and other professions who are proudly associated with Hubble. Their stories collectively communicate the excitement and reward of careers related to space science and technology.

Hubble space telescope↗

NASA NTRS2004

Alssat Development Status and Its Applications in Trade Studies

The development of the Advanced Life Support (ALS) Sizing Analysis Tool (ALSSAT) using Microsoft® Excel was initiated by the Crew and Thermal Systems Division (CTSD) of Johnson Space Center (JSC) in 1997 to support the ALS and Exploration Offices in Environmental Control and Life Support System (ECLSS) design and studies. It aids the user in performing detailed sizing of the ECLSS based on suggested default values or user inputs for different combinations of the ALS regenerative system technologies (Ref. 1, 2). This analysis tool will assist the user in performing ECLSS preliminary design and trade studies as well as system optimization efficiently and economically. Since ALSSAT's latest publication in ICES 2001 (Ref. 1) describing the development of ALSSAT with its Air Revitalization Subsystem (ARS), Water Management Subsystem (WMS), and Biomass Subsystem (Biomass) mass balance sheets, ALSSAT has been expanded to include mass balance and sizing models for the remaining three ALS subsystems, namely, the Solid Waste Management Subsystem (SWMS), the Food Management Subsystem (FMS), and the Thermal Control Subsystem (TCS). The external interfaces, including the Extravehicular Activities (EVA) and Human Accommodations (HA), were implemented into ALSSAT in 2002. The overall mass balance sheet, which integrates the six ALS subsystems and the external interfaces applicable to the ECLSS, was also developed. In 2003, ALSSAT was upgraded to include the consideration of redundancy and contingency options in the ECLSS, as well as more ALS regenerative technology selections. ALSSAT has been used for the Metric Calculation for FY02 and FY03 (Ref. 3). Several trade studies were conducted in 2003. The analytical results will be presented in this paper.

Yeh, H. Y. (Jannivine)↗

NASA NTRS2003

Overview of NASA GRC Stirling Technology Development

The Stirling Radioisotope Generator (SRG) is currently being developed by Lockheed Martin Astronautics (LMA) under contract to the Depar1ment of Energy (DOE). The generator will be a high efficiency electric power source for NASA Space Science missions with the capability to operate in the vacuum of deep space or in an atmosphere such as on the surface of Mars. High system efficiency is obtained through the use of free-piston Stirling power conversion technology. Power output of the generator will be greater than 100 watts at the beginning of life with the decline in power being largely due to the decay of the plutonium heat source. In suppOl1 of the DOE SRG project, the NASA Glenn Research Center (GRC) has established a near-term technology effort to provide some of the critical data to ensure a successful transition to flight for what will be the first dynamic power system used in space. Initially, a limited number of technical areas were selected for the GRC effort, however this is now being expanded to more thoroughly cover a range of technical issues. The tasks include in-house testing of Stirling convertors and controllers, materials evaluation and heater head life assessment, structural dynamics, electromagnetic interference, organics evaluation, and reliability analysis. Most of these high-level tasks have several subtasks within. There is also an advanced technology effort that is complementary near-term technology effort. Many of the tests make use of the 55-We Technology Demonstration Convel10r (TDC). There have been multiple controller tests to support the LMA flight controller design effort. Preparation is continuing for a thermal/vacuum system demonstration. A pair of flight prototype TDC's have recently been placed on an extended test with unattended, continuous operation. Heater head life assessment efforts continue, with the material data being refined and the analysis moving toward the system perspective. Long-term magnet aging tests are continuing to characterize any possible aging in the strength or demagnetization resistance of the permanent magnets used in the linear alternator. In a parallel effort, higher performance magnets are also being evaluated. A reliability effort is being initiated that will help to guide the development activities with an increased focus on the necessary components and subsystems. Some other disciplines that are active in the GRC technology effort include structural dynamics, linear alternator analysis, EMI/EMC, controls, and mechanical design evaluation. This paper will provide an overview of some of the GRC technical efforts, including the current status, and a description of future efforts.

Schreiber, Jeffrey↗

NASA NTRS2015

The CheMin XRD on the Mars Science Laboratory Rover Curiosity: Construction, Operation, and Quantitative Mineralogical Results from the Surface of Mars

The Mars Science Laboratory mission was launched from Cape Canaveral, Florida on Nov. 26, 2011 and landed in Gale crater, Mars on Aug. 6, 2012. MSL's mission is to identify and characterize ancient "habitable" environments on Mars. MSL's precision landing system placed the Curiosity rover within 2 km of the center of its 20 X 6 km landing ellipse, next to Gale's central mound, a 5,000 meter high pile of laminated sediment which may contain 1 billion years of Mars history. Curiosity carries with it a full suite of analytical instruments, including the CheMin X-ray diffractometer, the first XRD flown in space. CheMin is essentially a transmission X-ray pinhole camera. A fine-focus Co source and collimator transmits a 50μm beam through a powdered sample held between X-ray transparent plastic windows. The sample holder is shaken by a piezoelectric actuator such that the powder flows like a liquid, each grain passing in random orientation through the beam over time. Forward-diffracted and fluoresced X-ray photons from the sample are detected by an X-ray sensitive Charge Coupled Device (CCD) operated in single photon counting mode. When operated in this way, both the x,y position and the energy of each photon are detected. The resulting energy-selected Co Kalpha Debye-Scherrer pattern is used to determine the identities and amounts of minerals present via Rietveld refinement, and a histogram of all X-ray events constitutes an X-ray fluorescence analysis of the sample.The key role that definitive mineralogy plays in understanding the Martian surface is a consequence of the fact that minerals are thermodynamic phases, having known and specific ranges of temperature, pressure and composition within which they are stable. More than simple compositional analysis, definitive mineralogical analysis can provide information about pressure/temperature conditions of formation, past climate, water activity and the like. Definitive mineralogical analyses are necessary to establish the origin or provenance of a sample. The search for evidence of extant or extinct life on Mars will initially be a search for evidence of present or past conditions supportive of life (e.g., evidence of water), not for life itself.Results of the first 1,000 sols (Mars days) will be discussed, including the discovery of the first habitable environment on Mars.

CheMin↗

NASA NTRS2011

Development and Deployment of Robonaut 2 to the International Space Station

The development of the Robonaut 2 (R2) system was a joint endeavor with NASA and General Motors, producing robots strong enough to do work, yet safe enough to be trusted to work near humans. To date two R2 units have been produced, designated as R2A and R2B. This follows more than a decade of work on the Robonaut 1 units that produced advances in dexterity, tele-presence, remote supervision across time delay, combining mobility with manipulation, human-robot interaction, force control and autonomous grasping. Design challenges for the R2 included higher speed, smaller packaging, more dexterous fingers, more sensitive perception, soft drivetrain design, and the overall implementation of a system software approach for human safety, At the time of this writing the R2B unit was poised for launch to the International Space Station (ISS) aboard STS-133. R2 will be the first humanoid robot in space, and is arguably the most sophisticated robot in the world, bringing NASA into the 21st century as the world's leader in this field. Joining the other robots already on ISS, the station is now an exciting lab for robot experiments and utilization. A particular challenge for this project has been the design and certification of the robot and its software for work near humans. The 3 layer software systems will be described, and the path to ISS certification will be reviewed. R2 will go through a series of ISS checkout tests during 2011. A taskboard was shipped with the robot that will be used to compare R2B's dexterous manipulation in zero gravity with the ground robot s ability to handle similar objects in Earth s gravity. R2's taskboard has panels with increasingly difficult tasks, starting with switches, progressing to connectors and eventually handling softgoods. The taskboard is modular, and new interfaces and experiments will be built up using equipment already on ISS. Since the objective is to test R2 performing tasks with human interfaces, hardware abounds on ISS and the crew will be involved to help select tasks that are dull, dirty or dangerous. Future plans for R2 include a series of upgrades, evolving from static IVA (Intravehicular Activity) operations, to mobile IVA, then EVA (Extravehicular Activity).

Ambrose, Robert O.↗