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At least 325 records · Page 18

A new process and equipment for waste minimization: Conversion of NO(x) scrubber liquor to fertilizer

A new emissions control system for the oxidizer scrubbers that eliminates the current oxidizer liquor waste and lowers the NO(x) emissions is described. Since fueling and deservicing spacecraft constitute the primary operations in which environmental emissions occur, this will eliminate the second largest waste stream at KSC. This effort is in accord with Executive Order No. 12856 (Federal Compliance with Right-to-Know Laws and Pollution Prevention Requirements, data 6 Aug. 1993) and Executive Order No. 12873 (Federal Acquisition, Recycling, and Waste Prevention, dated 20 Oct. 1993). A recent study found that the efficiencies of the oxidizer scrubbers during normal operations ranged from 70 percent to 99 percent. The new scrubber liquor starts with 1% hydrogen peroxide at a pH of 7 and the process control system adds hydrogen peroxide and potassium hydroxide to the scrubber liquor to maintain those initial conditions. The result is the formation of a solution of potassium nitrate, which is sold as a fertilizer. This report describes the equipment and procedures used to monitor and control the conversion of the scrubber liquor to fertilizer, while reducing the scrubber emissions.

Parrish, Clyde F.↗

In-Flight Operation of the Dawn Ion Propulsion System Through Orbit Capture at Vesta

The Dawn mission, part of NASA's Discovery Program, has as its goal the scientific exploration of the two most massive main-belt asteroids, Vesta and Ceres. The Dawn spacecraft was launched from Cape Canaveral Air Force Station on September 27, 2007 on a Delta -II 7925H-9.5 (Delta-II Heavy) rocket that placed the 1218 kg spacecraft into an Earth-escape trajectory. Onboard the spacecraft is an ion propulsion system (IPS) developed at the Jet Propulsion Laboratory which will provide most of the ?V needed for heliocentric transfer to Vesta, orbit capture at Vesta, transfer among Vesta science orbits, departure and escape from Vesta, heliocentric transfer to Ceres, orbit capture at Ceres, and transfer among Ceres science orbits. The first 80 days after launch were dedicated to the initial checkout of the spacecraft which was followed by about ten months of full-power thrusting leading to a Mars gravity assist in February 2009 that provided 1 km/s of heliocentric energy increase and is the only part of the mission following launch in which a needed velocity change is not accomplished by the IPS. Deterministic thrusting for heliocentric transfer to Vesta resumed in June 2009 and was concluded with orbit capture at Vesta in July 2011. IPS was operated for approximately 23,400 hours, consumed approximately 250 kg of xenon, and provided a delta-V of approximately 6.7 km/s to achieve orbit capture at Vesta. IPS performance characteristics are very close to the expected performance characteristics based on analysis performed pre-launch. The only significant problem to have occurred over the almost four years of IPS operations in flight was the temporary failure of a valve driver board in DCIU-1, resulting in a loss of thrust of approximately 29 hours. Thrusting operations resumed after switching to DCIU-2, and power cycling conducted after orbit capture indicates DCIU-1 is completely operational. After about three weeks of survey operations IPS will be used to maneuver the spacecraft as needed for science operations including orbit transfers. After approximately one year of science operations IPS will then be used for escape from Vesta and begin thrusting for cruise to Ceres with a planned arrival date at Ceres in February 2015. This paper provides an overview of Dawn's mission objectives and the results of Dawn IPS mission operations through orbit capture and the start of science operations at Vesta.

Garner, Charles E.↗

Individual Variability and Predictive Biomarkers of Human Sensitivity to Ionizing Radiation

High-linear energy transfer (LET) ionizing radiation is a major health hazard for astronauts who will be exposed to galactic cosmic rays during upcoming lunar and Mars missions. Predicting and mitigating personalized health risks from space radiation exposure requires understanding the factors underlying individual radiation sensitivity, which currently remain unknown. We started to address this challenge by identifying the genomic and demographic associations with sensitivity to low and high-LET ionizing radiation in the largest human sample cohort to date and by evaluating baseline DNA damage as a potential predictor of radiation responses. We have collected and irradiated peripheral blood mononuclear cells (PBMCs) from 768 healthy donors of matched ethnicity, 50/50 male/female, 18-70 years old. We have analyzed the responses of 576 donor PBMCs to irradiation with simulated galactic cosmic ray components: 350MeV/n 28Si, 350MeV/n 40Ar and 600MeV/n 56Fe, at 1.1 and 3 particles/100μm2 fluences, as well as 0.1Gy and 1Gy doses of gamma rays, at 4 and 24 hours post irradiation. We quantified post-irradiation DNA repair based on radiation-induced 53BP1+ foci formation, together with oxidative stress and cell death using a flow cytometry-based assay. We also assessed baseline levels of DNA repair in PBMCs at the time of sample collection prior to irradiation experiments. We observed a wide variability of subject- and LET-dependent radiation responses, with radiation-induced DNA repair foci increasing with LET, though oxidative stress being notably reduced by high-LET irradiation, potentially due to a switch between hydrogen peroxide and oxygen radical-based mechanisms. We also identified a relationship between few DNA repair foci at baseline and increased DNA repair after irradiation, accompanied by an alteration in immunoregulatory cytokine secretion, which might be adapted as biomarkers to predict ionizing radiation sensitivity. Among demographic variables, baseline foci levels were positively associated with age and latent cytomegalovirus infection. Finally, we have performed low-throughput whole genome sequencing of all samples and are currently in process of identifying the genes and pathways associated with low and high-LET ionizing radiation sensitivity in humans.

Space radiation, human spaceflight, DNA damage↗

The Contribution of Ionizing Starts to the Far-Infrared and Radio Emission in the Milky Way: Evidence for a Swept-up Shell and Diffuse Ionized Halo Around the W4 Chimney/Supershell

Normandeau have proposed that W4 is a galactic chimney, the only chimney to-date identified in our Galaxy. Using the recent approx. 1 min resolution IGA (Infrared Galaxy Atlas) and DRAO (Dominion Royal Astrophysical Observatory) CGPS (Canadian Galactic Plane Survey) galactic plane surveys we analyze the far-infrared and radio structure of the W 4 chimney/supershell. We show W4 has a swept-up partially ionized shell of gas and dust which is powered by the OCl 352 star cluster. Analysis of the dust column density establishes there is dense interstellar material below the shell, directly showing the dense material which caused the lower shell expansion to stall. Due to much lower densities above the Galactic plane, the upper W4 shell achieved 'breakout' to form a Galactic chimney. Although the shell appears ionization bounded, it is very inhomogenous and an ionized halo provides evidence of significant Lyman continuum leakage. A large fraction of the OCl 352 cluster photons escape to large distances and are available to ionize the WIM (warm ionized medium) component of the interstellar medium.

Terebey, Susan↗

Space Station design integration

This paper discusses the top Program level design integration process which involves the integration of a US Space Station manned base that consists of both US and international Elements. It explains the form and function of the Program Requirements Review (PRR), which certifies that the program is ready for preliminary design, the Program Design Review (PDR), which certifies the program is ready to start the detail design, and the Critical Design Review (CDR), which certifies that the program is completing a design that meets the Program objectives. The paper also discusses experience, status to date, and plans for continued system integration through manufacturing, testing and final verification of the Space Station system performance.

Carlisle, Richard F.↗

MOLA II Laser Transmitter Calibration and Performance

The goal of the document is to explain the algorithm for determining the laser output energy from the telemetry data within the return packets from MOLA II. A simple algorithm is developed to convert the raw start detector data into laser energy, measured in millijoules. This conversion is dependent on three variables, start detector counts, array heat sink temperature and start detector temperature. All these values are contained within the return packets. The conversion is applied to the GSFC Thermal Vacuum data as well as the in-space data to date and shows good correlation.

Afzal, Robert S.↗

NASA’s Rotating Detonation Rocket Engine Development

The Rotating Detonation Rocket Engine has maintained steady development at NASA with many staggering performance advantages demonstrated to date over the state-of-the-art (SOA). The implementation of additive manufacturing and specialized NASA developed alloys have enabled rapid maturation of the technology. Several hot fire test projects have been successfully conducted at Marshall Space Flight Center under an early career initiative project funded by NASA Space Technology Mission Directorate. In addition, a new start Technology Demonstration Mission (TDM) project has been funded to investigate challenges relating to integration of turbomachinery with an RDRE thrust chamber assembly. This engine system demonstration will leverage a methane/oxygen single shaft turbopump with fuel rich gas generator and a 10,000 lbf thrust chamber assembly. The configuration was down selected based on feedback from both US industry collaborators and power balance trades in combination with technical feasibility. To date, industry has identified several use cases for RDRE ranging from thruster to primary launch vehicle propulsion. A wide range of fuel and oxidizers were also identified including but not limited to Methane, Kerosene and other liquid hydrocarbon (LH) fuels, and hydrogen. Recent work at NASA and in partnership with NASA has investigated these major fuels of interest with oxygen, air, and hydrogen peroxide (HTP) for various applications. NASA Marshall has already investigated the use of hydrogen/oxygen, methane/oxygen, kerosene/oxygen, and has plans in partnership with industry and academia to investigate LH/air and LH/HTP. In addition to propellants, hardware geometry has been investigated with some critical lessons learned toward greater theoretical performance over the SOA. To this end, several experimental and computational activities are ongoing to further advance the RDRE towards flight missions. Given the rate of advancement, it is highly likely the technology will be flown in space mission in the coming decade. This work documents and overviews many of these investigations and overviews NASA’s future plans for the technology maturation.

Thomas Teasley↗

A View from Space: Evolution of the 1997-98 El Nino and La Nina

After the last extreme El Nino in 1982-1983, an extensive in situ observing system was deployed in the tropical Pacific Ocean in support of monitoring and predicting El Nino. Within the past ten years a series of ocean and atmosphere remote sensing satellites have been launched that serve to supplement and enhance the observations being taken at the surface, and at depth, in the equatorial Pacific Ocean. The 1997-1998 "El Nino Event of the Century" has been the best monitored El Nino on record. The 1997-1998 El Nino will be the first time a major El Nino event and subsequent La Nina will have been observed from start to finish from a combination of remotely-sensed measurements of sea surface temperature, sea surface topography, sea surface winds, ocean color, and precipitation. Among some of the lessons learned to date from the 1997-1998 event have been the need for global observations in addition to just those in the equatorial Pacific Ocean. In this presentation the evolution of the 1997-1998 El Nino will be depicted from the unique vantage point provided by these space-based observations as analyzed separately, and together as a representation of the coupled system. Comparisons and contrasts with the evolution 1982-1983 El Nino and how the in situ and space-based observations complement each other will be discussed.

Busalacchi, Antonio J.↗

A View from Space: Evolution of the 1997-1998 El Nino and La Nina

After the last extreme El Nino in 1982-1983, an extensive in situ observing system was deployed in the tropical Pacific Ocean in support of monitoring and predicting El Nino. Within the past ten years a series of ocean and atmosphere remote sensing satellites have been launched that serve to supplement and enhance the observations being taken at the surface, and at depth, in the equatorial Pacific Ocean. The 1997-1998 "El Nino Event of the Century" has been the best monitored El Nino on record. The 1997-1998 El Nino will be the first time a major El Nino event and subsequent La Nina will have been observed from start to finish from a combination of remotely-sensed measurements of sea surface temperature, sea surface topography, sea surface winds, ocean color, and precipitation. Among some of the lessons learned to date from the 1997-1998 event have been the need for global observations in addition to just those in the equatorial Pacific Ocean. In this presentation the evolution of the 1997-1998 El Nino will be depicted from the unique vantage point provided by these space-based observations as analyzed separately, and together as a representation of the coupled system. Comparisons and contrasts with the evolution 1982-1983 El Nino and how the in situ and space-based observations complement each other will be discussed.

Busalacchi, Antonio J.↗

A View From Space: Evolution of the 1997-1998 El Nino and La Nina

After the last extreme El Nino in 1982-1983, an extensive in situ observing system was deployed in the tropical Pacific Ocean in support of monitoring and predicting El Nino. Within the past ten years a series of ocean and atmosphere remote sensing satellites have been launched that serve to supplement and enhance the observations being taken at the surface, and at depth, in the equatorial Pacific Ocean. The 1997-1998 "El Nino Event of the Century" has been the best monitored El Nino on record. The 1997-1998 El Nino will be the first time a major El Nino event and subsequent La Nina will have been observed from start to finish from a combination of remotely-sensed measurements of sea surface temperature, sea surface topography, sea surface wind, ocean color, and precipitation, Among some of the lessons learned to date from the 1997-1998 event have been the need for global observation in addition to just those in the equatorial Pacific Ocean. In this presentation the evolution of the 1997-1998 El Nino will be depicted from the unique vantage point provided by these space-based observations as analyzed separately, and together as a representation of the coupled system. Comparisons and contrasts with the evolution 1982-1983 El Nino and how the in situ and space-based observations complement each other will be discussed.

Busalacchi, Antonio↗

Using DNA Damage to Investigate the Individual Variability of Human Sensitivity to Ionizing Radiation

High-LET ionizing radiation is a major occupational health hazard for astronauts, but risk assessment remains elusive due to limited epidemiological data. Identifying genetic factors modulating the individual radiation response may be the most effective strategy to provide individualized risk management for long-duration high-radiation missions. We have started tackling the challenge of predicting individual risks by identifying human genetic loci associated with various radiation sensitivity phenotypes in primary blood mononuclear cells from a relatively large healthy human cohort. To date, we have performed the isolation of PBMCs from 768 subjects of the same ethnicity, and irradiated PBMCs from 576 subjects with 1 and 3 particles/100µm2 of 600 MeV/n 56Fe, 350 MeV/n 40Ar and 350 MeV/n 28Si ions. The phenotypes of interest were: number of radiation-induced foci (or RIFs), CellROX oxidative stress responses and cell death, at 4h and 24h following irradiation. We have observed a significant inter-individual variability at 0 Gy between the 576 studied subjects, with a mean fold difference between the 10% lowest and highest responders of 5.6 of RIFs/cell, 7.9 in mean CellRox intensity, and 9.3 in percentage of dead cells. In order to better assess genetic factors influencing DNA repair, we used a metric previously introduced by our group to sort out radiation sensitivity phenotypes in mice: i.e. the ratio of the first to the second slope of RIFs/cell (between 0 and 1, and between 1 and 3 particle/100µm2). Preliminary data on 192 individuals showed a distribution of low-dose responders (ratio > 1) to high-dose responders (ratio < 1) at 4h of 12%, 55% and 52% respectively for Fe, Ar and Si. The average value for the first and the second slopes was very similar for the two lowest LET (0.10 [-0.26;0.58] and 0.09 [-0.45;0.41] for Ar, 0.07 [-0.27;0.38] and 0.08 [-0.19;0.42] for Si), indicating a linear dose response across both fluence. Fe showed clear saturation for the highest dose with a slope of -0.09 [-0.86;1.51] against 0.68 [-2.21;2.20] for the low dose range, which probably reflects that many PBMCs are beyond repair at the high dose. Note that other significances were found for additional factors such as BMI and age whereas none were found for sex. GWAS will be performed on all phenotypes upon completion of measurements.

Pariset, E.↗

Using DNA Damage to Investigate the Individual Variability of Human Sensitivity to Ionizing Radiation

High-LET ionizing radiation is a major occupational health hazard for astronauts, but risk assessment remains elusive due to limited epidemiological data. Identifying genetic factors modulating the individual radiation response may be the most effective strategy to provide individualized risk management for long-duration high-radiation missions. We have started tackling the challenge of predicting individual risks by identifying human genetic loci associated with various radiation sensitivity phenotypes in primary blood mononuclear cells from a relatively large healthy human cohort. To date, we have performed the isolation of PBMCs from 768 subjects of the same ethnicity, and irradiated PBMCs from 576 subjects with 1 and 3 particles/100µm2 of 600 MeV/n 56Fe, 350 MeV/n 40Ar and 350 MeV/n 28Si ions. The phenotypes of interest were: number of radiation-induced foci (or RIFs), CellROX oxidative stress responses and cell death, at 4h and 24h following irradiation. We have observed a significant inter-individual variability at 0 Gy between the 576 studied subjects, with a mean fold difference between the 10% lowest and highest responders of 5.6 of RIFs/cell, 7.9 in mean CellRox intensity, and 9.3 in percentage of dead cells. In order to better assess genetic factors influencing DNA repair, we used a metric previously introduced by our group to sort out radiation sensitivity phenotypes in mice: i.e. the ratio of the first to the second slope of RIFs/cell (between 0 and 1, and between 1 and 3 particle/100µm2). Preliminary data on 192 individuals showed a distribution of ?low-dose responders? (ratio > 1) to ?high-dose responders? (ratio < 1) at 4h of 12%, 55% and 52% respectively for Fe, Ar and Si. The average value for the first and the second slopes was very similar for the two lowest LET (0.10 [-0.26;0.58] and 0.09 [-0.45;0.41] for Ar, 0.07 [-0.27;0.38] and 0.08 [-0.19;0.42] for Si), indicating a linear dose response across both fluence. Fe showed clear saturation for the highest dose with a slope of -0.09 [-0.86;1.51] against 0.68 [-2.21;2.20] for the low dose range, which probably reflects that many PBMCs are beyond repair at the high dose. Note that other significances were found for additional factors ? such as BMI and age ? whereas none were found for sex. GWAS will be performed on all phenotypes upon completion of measurements.

Pariset, E.↗

Radar Observations from the Haystack Ultrawideband Satellite Imaging Radar in 2019

The NASA Orbital Debris Program Office (ODPO) relies primarily on ground-based radar measurements to characterize the distribution of small debris, down to approximately 3 mm depending upon altitude and the sensor used, in low Earth orbit (LEO). Since the early 1990’s, the Massachusetts Institute of Technology (MIT) Lincoln Laboratory (LL) has been collecting radar measurements for the NASA ODPO under agreements with the U.S. Department of Defense. The Haystack Ultrawideband Satellite Imaging Radar (HUSIR) is the primary ground-based radar sensor used by the ODPO and provides data on orbital debris down to an approximate size of 5.5 mm below 1000km altitude using the NASA size estimation model (SEM). Since orbital debris of this size are a significant risk to both human and robotic missions in LEO, the sensitivity of this radar makes it a high-value sensor. The NASA ODPO radar measurements are conducted on a continual basis for monitoring and enabling modeling of the orbital debris environment over time. HUSIR observations from 2019 are the most recent snapshot of the environment that has been measured and analyzed to date. In recent years, HUSIR measurements indicated relatively stable populations for the orbital debris objects that it is able to detect. In 2019, several interesting events happened on-orbit, including the start of large constellation deployments into LEO, as well as the Indian anti-satellite test with Microsat-R (International Designator 2019-006A, U.S. Strategic Command Space Surveillance Network catalog number 43947). Due to these events, coupled with a general increase in the number of missions and participants launching missions in recent years, continual monitoring is necessary to determine the effects of this increased activity on the orbital debris environment. This paper will explore the results of the 2019 HUSIR radar measurements, including above-average flux measurements at lower LEO altitudes and the evolution of the flux during the time of observations.

James Murray↗

Radar Observations from the Haystack Ultrawideband Satellite Imaging Radar in 2019

The NASA Orbital Debris Program Office (ODPO) relies primarily on ground-based radar measurements to characterize the distribution of small debris, down to approximately 3 mm depending upon altitude and the sensor used, in low Earth orbit (LEO). Since the early 1990’s, the Massachusetts Institute of Technology (MIT) Lincoln Laboratory (LL) has been collecting radar measurements for the NASA ODPO under agreements with the U.S. Department of Defense. The Haystack Ultrawideband Satellite Imaging Radar (HUSIR) is the primary ground-based radar sensor used by the ODPO and provides data on orbital debris down to an approximate size of 5.5 mm below 1000km altitude using the NASA size estimation model (SEM). Since orbital debris of this size are a significant risk to both human and robotic missions in LEO, the sensitivity of this radar makes it a high-value sensor. The NASA ODPO radar measurements are conducted on a continual basis for monitoring and enabling modeling of the orbital debris environment over time. HUSIR observations from 2019 are the most recent snapshot of the environment that has been measured and analyzed to date. In recent years, HUSIR measurements indicated relatively stable populations for the orbital debris objects that it is able to detect. In 2019, several interesting events happened on-orbit, including the start of large constellation deployments into LEO, as well as the Indian anti-satellite test with Microsat-R (International Designator 2019-006A, U.S. Strategic Command Space Surveillance Network catalog number 43947). Due to these events, coupled with a general increase in the number of missions and participants launching missions in recent years, continual monitoring is necessary to determine the effects of this increased activity on the orbital debris environment. This paper will explore the results of the 2019 HUSIR radar measurements, including above-average flux measurements at lower LEO altitudes and the evolution of the flux during the time of observations.

James Murray↗

Turbulence measurements in hypersonic boundary layers using constant-temperature anemometry and Reynolds stress measurements in hypersonic boundary layers

The primary objective in the two research investigations performed under NASA Langley sponsorship (Turbulence measurements in hypersonic boundary layers using constant temperature anemometry and Reynolds stress measurements in hypersonic boundary layers) has been to increase the understanding of the physics of hypersonic turbulent boundary layers. The study began with an extension of constant-temperature thermal anemometry techniques to a Mach 11 helium flow, including careful examinations of hot-wire construction techniques, system response, and system calibration. This was followed by the application of these techniques to the exploration of a Mach 11 helium turbulent boundary layer (To approximately 290 K). The data that was acquired over the course of more than two years consists of instantaneous streamwise mass flux measurements at a frequency response of about 500 kHz. The data are of exceptional quality in both the time and frequency domain and possess a high degree of repeatability. The data analysis that has been performed to date has added significantly to the body of knowledge on hypersonic turbulence, and the data reduction is continuing. An attempt was then made to extend these thermal anemometry techniques to higher enthalpy flows, starting with a Mach 6 air flow with a stagnation temperature just above that needed to prevent liquefaction (To approximately 475 F). Conventional hot-wire anemometry proved to be inadequate for the selected high-temperature, high dynamic pressure flow, with frequent wire breakage and poor system frequency response. The use of hot-film anemometry has since been investigated for these higher-enthalpy, severe environment flows. The difficulty with using hot-film probes for dynamic (turbulence) measurements is associated with construction limitations and conduction of heat into the film substrate. Work continues under a NASA GSRP grant on the development of a hot film probe that overcomes these shortcomings for hypersonic flows. Each of the research tasks performed during the NASA Langley research grants is discussed separately below.

Spina, Eric F.↗

Throttling Characteristics of the RL10 Derivative Common Extensible Cryogenic Engine -- Demo 1.6 and 1.7 Test Results

The Common Extensible Cryogenic Engine (CECE) is a deep throttling cryogenic Lunar Module Descent Engine (LMDE) technology development demonstrator based on the Pratt & Whitney Rocketdyne (PWR) RL10 engine. Previous testing on this engine occurred during 2006 as Demo 1.0, then Demo 1.5 in 2007, Demo 1.6 in 2008 and finally Demo 1.7 in 2010. A review of Demo 1.0, 1.5, and preliminary results of 1.6 were reported in previous JANNAF papers. Demo 1.6 was tested at the PWR E-6 test facility in November 2008. The primary goal of this series was to mitigate low frequency combustion instability observed at low power levels. To mitigate the chug, the Demo 1.6 injector was modified from the previous configurations to include an approximately 0.050 inch thick teflon-type spray-on insulation to reduce heat transfer to the LOX manifold, which was believed to be a significant contributor to the low power instability. In addition, gaseous helium injection into the LOX manifold was used as a means to stabilize the system. Also explored in this test series was mitigation for a low power 1 Hz fuel system oscillation caused by sub-critical hydrogen boiling in the chamber cooling jacket. Reduced area gas venturis were utilized to avoid the 1 Hz fuel-size oscillation by keeping the cooling jacket supercritical down to lower engine power levels. Demo 1.7 began testing in March 2010. Its primary objectives were to demonstrate closed loop control capability on mixture ratio and chamber pressure, start to lower power levels and increased throttling ramp rates. Secondary test objectives that are discussed include multiple engine starts, higher mixture ratio excursions and additional time at low power level. While the complete test series and data reduction is not yet complete for Demo 1.7, an overview and up-to-date status is provided.

Devine, Matthew K.↗

A thermal shield concept for the Solar Probe mission

The Solar Probe spacecraft will travel to within 4 solar radii of the sun's center while performing a variety of fundamental experiments in space physics. Exposure to 2900 earth suns (400 W/sq cm) at perihelion imposes severe thermal and material demands on a solar shield system designed to protect the payload that will reside within the shield's shadow envelope or umbra. The design of the shield subsystem is a thermal/materials challenge requiring new technology development. While currently in the preproject study phase, anticipating a 1995 project start, shield preliminary design efforts are currently underway. This paper documents the current status of the mission concept, the materials issues, the configuration concept for the shield subsystem, the current configuration studies performed to date, and the required material testing to provide a database to support a design effort required to develop the shield subsystem.

Miyake, Robert N.↗

Sensorimotor Application of Proposed Methods to Combine the Effects of Multiple Countermeasures for PRisM

Risk associated with human systems is challenging to quantify but is critical for the mission planning and decision making required to enable future Lunar and Martian missions. To address this gap, the Crew Health and Performance-Probabilistic Risk Assessment (CHP-PRA) project is developing an integrated computational model for CHP mission risk. Much like how MEDPRAT is designed to allow medical resource trades informed by medical risk, CHP-PRA will enable analogous trades in human system risks across multiple CHP functions and capabilities. Human performance is one component of the risk intended to be captured by CHP-PRA through the Performance Risk Model (PRisM). The sensorimotor risk area provides a good frame of reference for investigating the structure of a performance model because most tasks that astronauts are expected to perform require input from the sensory system and/or movement/motor control. Additionally, sensorimotor countermeasures are an area of particular concern for NASA’s Human Research Program because of the increased sensorimotor risk associated with surface operations in Lunar and Martian missions. Thus, a tool that can quickly compare risk reductions of potential countermeasures would be beneficial in guiding research and development of effective countermeasures. In this proof of concept, we present a systematic way to combine multiple performance data sets for humans subjected to different countermeasures such that we can predict the countermeasure(s) that optimize astronaut performance on relevant tasks. PRisM assumes that both the tests that are used to measure countermeasure effectiveness (input data) and the tasks we use to represent astronaut performance, can be broken down and represented as a function/vector of the human systems required to perform that test/task. Through mathematical combination, test data are used to predict performance on astronaut tasks that use similar systems. We propose that when combining countermeasures evaluated using the same test, that only one value should be used to represent their combined effectiveness. We start our analysis with the assumption that two countermeasures together will perform better than each countermeasure individually. Our initial implementation of this framework compares various space motion sickness countermeasures and the most up to date analysis will be demonstrated at the IWS.

Caroline R Austin↗