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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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All sourcesNASA NTRSDOE OSTI
NASA NTRS1999

Signal processing related to the vestibulo-ocular reflex during combined angular rotation and linear translation of the head

The contributions of vestibular nerve afferents and central vestibular pathways to the angular (AVOR) and linear (LVOR) vestibulo-ocular reflex were studied in squirrel monkeys during fixation of near and far targets. Irregular vestibular afferents did not appear to be necessary for the LVOR, since when they were selectively silenced with galvanic currents the LVOR was essentially unaffected during both far- and near-target viewing. The linear translation signals generated by secondary AVOR neurons in the vestibular nuclei were, on average, in phase with head velocity, inversely related to viewing distance, and were nearly as strong as AVOR-related signals. We suggest that spatial-temporal transformation of linear head translation signals to angular eye velocity commands is accomplished primarily by the addition of viewing distance multiplied, centrally integrated, otolith regular afferent signals to angular VOR pathways.

NASA Discipline Neuroscience↗
NASA NTRS1999

Human sympathetic and vagal baroreflex responses to sequential nitroprusside and phenylephrine

We evaluated a method of baroreflex testing involving sequential intravenous bolus injections of nitroprusside followed by phenylephrine and phenylephrine followed by nitroprusside in 18 healthy men and women, and we drew inferences regarding human sympathetic and vagal baroreflex mechanisms. We recorded the electrocardiogram, photoplethysmographic finger arterial pressure, and peroneal nerve muscle sympathetic activity. We then contrasted least squares linear regression slopes derived from the depressor (nitroprusside) and pressor (phenylephrine) phases with 1) slopes derived from spontaneous fluctuations of systolic arterial pressures and R-R intervals, and 2) baroreflex gain derived from cross-spectral analyses of systolic pressures and R-R intervals. We calculated sympathetic baroreflex gain from integrated muscle sympathetic nerve activity and diastolic pressures. We found that vagal baroreflex slopes are less when arterial pressures are falling than when they are rising and that this hysteresis exists over pressure ranges both below and above baseline levels. Although pharmacological and spontaneous vagal baroreflex responses correlate closely, pharmacological baroreflex slopes tend to be lower than those derived from spontaneous fluctuations. Sympathetic baroreflex slopes are similar when arterial pressure is falling and rising; however, small pressure elevations above baseline silence sympathetic motoneurons. Vagal, but not sympathetic baroreflex gains vary inversely with subjects' ages and their baseline arterial pressures. There is no correlation between sympathetic and vagal baroreflex gains. We recommend repeated sequential nitroprusside followed by phenylephrine doses as a simple, efficientmeans to provoke and characterize human vagal and sympathetic baroreflex responses.

NASA Discipline Cardiopulmonary↗
NASA NTRS2006

Fuel Cell Airframe Integration Study for Short-Range Aircraft: Aircraft Propulsion and Subsystems Integration Evaluation - Volume 1

The objective of this study is to define the functionality and evaluate the propulsion and power system benefits derived from a Solid Oxide Fuel Cell (SOFC) based Auxiliary Power Unit (APU) for a future short range commercial aircraft, and to define the technology gaps to enable such a system. United Technologies Corporation (UTC) Integrated Total Aircraft Power System (ITAPS) methodologies were used to evaluate a baseline aircraft and several SOFC architectures. The technology benefits were captured as reductions of the mission fuel burn, life cycle cost, noise and emissions. As a result of the study, it was recognized that system integration is critical to maximize benefits from the SOFC APU for aircraft application. The mission fuel burn savings for the two SOFC architectures ranged from 4.7 percent for a system with high integration to 6.7 percent for a highly integrated system with certain technological risks. The SOFC APU itself produced zero emissions. The reduction in engine fuel burn achieved with the SOFC systems also resulted in reduced emissions from the engines for both ground operations and in flight. The noise level of the baseline APU with a silencer is 78 dBA, while the SOFC APU produced a lower noise level. It is concluded that a high specific power SOFC system is needed to achieve the benefits identified in this study. Additional areas requiring further development are the processing of the fuel to remove sulfur, either on board or on the ground, and extending the heat sink capability of the fuel to allow greater waste heat recovery, resolve the transient electrical system integration issues, and identification of the impact of the location of the SOFC and its size on the aircraft.

Gummalla, Mallika↗
NASA NTRS2007

Comparative MicroRNA Expression Patterns in Fibroblasts after Low and High Doses of Low-LET Radiation Exposure

Exposure to ionizing radiation causes DNA damage to cells, and provokes a plethora of cellular responses controlled by unique gene-directed signaling pathways. MicroRNAs (miRNAs) are small (~22-nucleotide), non-coding RNAs which functionally silence gene expression by either degrading the messages or inhibiting translation. Here we investigate radiation-dependent changes in these negative regulators by comparing the expression patterns of all 462 known human miRNAs in fibroblasts, after exposure to low (0.1 Gy) or high (2 Gy) doses of X-rays at 30 min, 2, 6 and 24 hrs post-treatment. The expression patterns of microRNAs after low and high doses of radiation show a similar qualitative down-regulation trend at early (0.5 hr) and late (24 hr) time points, with a quantitatively steeper slope following the 2 Gy exposures. Interestingly, an interruption of this downward trend is observed after the 2 Gy exposure, i.e. a significant up-regulation of microRNAs at 2 hrs, then reverting to the downward trend by 6 hrs; this interruption at the intermediate time point was not observed with the 0.1 Gy exposure. At the early time point (0.5 hr), candidate gene targets of selected down-regulated microRNAs, common to both 0.1 and 2 Gy exposures, were those functioning in chromatin remodeling. Candidate target genes of unique up-regulated microRNAs seen at a 2 hr intermediate time point, after the 2 Gy exposure only, are those involved in cell death signaling. Finally, putative target genes of down-regulated microRNAs seen at the late (24 hr) time point after either doses of radiation are those involved in the up-regulation of DNA repair, cell signaling and homeostasis. Thus we hypothesize that after radiation exposure, microRNAs acting as hub negative regulators for unique signaling pathways needed to be down-regulated so as to de-repress their target genes for the proper cellular responses, including DNA repair and cell maintenance. The unique microRNAs up-regulated at 2 hr after 2 Gy suggest the cellular response to functionally suppress the apoptotic death signaling reflex after exposure to high dose radiation. Further analyses with transcriptome and global proteomic profiling will validate the reciprocal expression of signature microRNAs selected in our radiation-exposed cells, and their candidate target gene families, and test our hypothesis that unique radiation-specific microRNAs are keys in governing signaling responses for damage control of this environmental hazard.

Maes, Olivier C.↗
NASA NTRS2008

Radio-sensitization of Prostate Cancer Cells by Monensin Treatment and its associated Gene Expression Profiling Changes

Radio-resistant or recurrent prostate cancer represents a serious health risk for approximately 20%-30% of patients treated with primary radiation therapy for clinically localized prostate cancer. Here, we investigated the effect of monensin on sensitizing radiation mediated cell killing of two radio-resistant prostate cell lines Lncap (P53+ and AR+) and PC3 (P53- and AR-). Treatment with monensin alone (5 micromoles-20 micromoles) showed a significant direct cell killing of Lncap (10-30%), but not PC3 cells. Monensin was also shown to successfully sensitize Lncap cells to X-ray radiation (2Gy-10Gy) mediated cell death, up to 50% of killing with the combined treatment. To better understand the mechanisms of radio-resistance of these two cell lines and their different response to monensin, the apoptosis related gene expression profiles in both cell lines were analyzed using cDNA PCR array. Without any treatment, PC3 showed a much higher expression level of antiapoptosis genes than Lncap in the BCL2 family, the caspase/card family and the TNF ligand/receptor family. At 2 hr after 20 micormolar monensin treatment alone, only the TRAF and CIDE family showed a greater induction in Lncap cells than in PC3. Exposures to 10 Gy X-rays alone of Lncap cells significantly induced gene expression levels in the death and death receptor domain family, the TNF ligand and receptor family, and apoptotic group of BCL2 family; whereas exposures of PC3 induced only the expression of genes in the anti-apoptosis group of CASP and CARD family. Furthermore, we selectively suppressed the expression of several anti-apoptosis genes (BCL-xl, Bcl2A1, BIRC2, BIRC3 and CASP2) in PC3 cells by using the siRNA treatment. Exposure to 10Gy X-rays alone showed an enhanced cell killing (about 15%) in BCL-x1 silenced cells, but not in cells with siRNA treatment targeting other anti-apoptosis genes. We also exposed PC3 cells to protons in the Bragg peak region to compare the effectiveness of cell killing of X-rays. Interestingly, in comparison to X-rays, protons significantly reduced the gene expression in the anti-apoptosis family, suggesting that proton treatment may be more effective for PC3 cells. As a conclusion, monensin was found to sensitize Lncap cells, but not PC3, and over-expression of Bcl-xl cells may be responsible for the radio- or chemo-resistance characteristics of PC3 cells.

Zhang Ye↗
NASA NTRS2008

G-Guidance Interface Design for Small Body Mission Simulation

The G-Guidance software implements a guidance and control (G and C) algorithm for small-body, autonomous proximity operations, developed under the Small Body GN and C task at JPL. The software is written in Matlab and interfaces with G-OPT, a JPL-developed optimization package written in C that provides G-Guidance with guaranteed convergence to a solution in a finite computation time with a prescribed accuracy. The resulting program is computationally efficient and is a prototype of an onboard, real-time algorithm for autonomous guidance and control. Two thruster firing schemes are available in G-Guidance, allowing tailoring of the software for specific mission maneuvers. For example, descent, landing, or rendezvous benefit from a thruster firing at the maneuver termination to mitigate velocity errors. Conversely, ascent or separation maneuvers benefit from an immediate firing to avoid potential drift toward a second body. The guidance portion of this software explicitly enforces user-defined control constraints and thruster silence times while minimizing total fuel usage. This program is currently specialized to small-body proximity operations, but the underlying method can be generalized to other applications.

Acikmese, Behcet↗
NASA NTRS2007

Applications for Subvocal Speech

A research and development effort now underway is directed toward the use of subvocal speech for communication in settings in which (1) acoustic noise could interfere excessively with ordinary vocal communication and/or (2) acoustic silence or secrecy of communication is required. By "subvocal speech" is meant sub-audible electromyographic (EMG) signals, associated with speech, that are acquired from the surface of the larynx and lingual areas of the throat. Topics addressed in this effort include recognition of the sub-vocal EMG signals that represent specific original words or phrases; transformation (including encoding and/or enciphering) of the signals into forms that are less vulnerable to distortion, degradation, and/or interception; and reconstruction of the original words or phrases at the receiving end of a communication link. Potential applications include ordinary verbal communications among hazardous- material-cleanup workers in protective suits, workers in noisy environments, divers, and firefighters, and secret communications among law-enforcement officers and military personnel in combat and other confrontational situations.

Jorgensen, Charles↗
NASA NTRS2009

The New Weather Radar for America's Space Program in Florida: A Temperature Profile Adaptive Scan Strategy

A new weather radar is being acquired for use in support of America s space program at Cape Canaveral Air Force Station, NASA Kennedy Space Center, and Patrick AFB on the east coast of central Florida. This new radar replaces the modified WSR-74C at Patrick AFB that has been in use since 1984. The new radar is a Radtec TDR 43-250, which has Doppler and dual polarization capability. A new fixed scan strategy was designed to best support the space program. The fixed scan strategy represents a complex compromise between many competing factors and relies on climatological heights of various temperatures that are important for improved lightning forecasting and evaluation of Lightning Launch Commit Criteria (LCC), which are the weather rules to avoid lightning strikes to in-flight rockets. The 0 C to -20 C layer is vital since most generation of electric charge occurs within it and so it is critical in evaluating Lightning LCC and in forecasting lightning. These are two of the most important duties of 45 WS. While the fixed scan strategy that covers most of the climatological variation of the 0 C to -20 C levels with high resolution ensures that these critical temperatures are well covered most of the time, it also means that on any particular day the radar is spending precious time scanning at angles covering less important heights. The goal of this project is to develop a user-friendly, Interactive Data Language (IDL) computer program that will automatically generate optimized radar scan strategies that adapt to user input of the temperature profile and other important parameters. By using only the required scan angles output by the temperature profile adaptive scan strategy program, faster update times for volume scans and/or collection of more samples per gate for better data quality is possible, while maintaining high resolution at the critical temperature levels. The temperature profile adaptive technique will also take into account earth curvature and refraction when geo-locating the radar beam (i.e., beam height and arc distance), including non-standard refraction based on the user-input temperature profile. In addition to temperature profile adaptivity, this paper will also summarize the other requirements for this scan strategy program such as detection of low-level boundaries, detection of anvil clouds, reducing the Cone Of Silence, and allowing for times when deep convective clouds will not occur. The adaptive technique will be carefully compared to and benchmarked against the new fixed scan strategy. Specific environmental scenarios in which the adaptive scan strategy is able to optimize and improve coverage and resolution at critical heights, scan time, and/or sample numbers relative to the fixed scan strategy will be presented.

Carey, L. D.↗
NASA NTRS2010

High LET Radiation Can Enhance TGF(Beta) Induced EMT and Cross-Talk with ATM Pathways

The TGF(Beta) pathway has been shown to regulate or directly interact with the ATM pathway in the response to radiation in mammary epithelial cells. We investigated possible interactions between the TGF(Beta) and ATM pathways following simulated space radiation using hTERT immortalized human esophageal epithelial cells (EPC-hTERT), mink lung epithelial cells (Mv1lu), and several human fibroblast cell lines. TGF(Beta) is a key modulator of the Epithelial-Mesenchymal Transition (EMT), important in cancer progression and metastasis. The implication of EMT by radiation also has several lines of developing evidence, however is poorly understood. The identification of TGF(Beta) induced EMT can be shown in changes to morphology, related gene over expression or down regulation, which can be detected by RT-PCR, and immunostaining and western blotting. In this study, we have observed morphologic and molecular alternations consistent with EMT after Mv1lu cells were treated with TGF(Beta) High LET radiation enhanced TGF(Beta) mediated EMT with a dose as low as 0.1Gy. In order to consider the TGF(Beta) interaction with ATM we used a potent ATM inhibitor Ku55933 and investigated gene expression changes and Smad signaling kinetics. Ku559933 was observed to reverse TGF(Beta) induced EMT, while this was not observed in dual treated cells (radiation+TGF(Beta)). In EPC-hTERT cells, TGF(Beta) alone was not able to induce EMT after 3 days of application. A combined treatment with high LET, however, significantly caused the alteration of EMT markers. To study the function of p53 in the process of EMT, we knocked down P53 through RNA interference. Morphology changes associated with EMT were observed in epithelial cells with silenced p53. Our study indicates: high LET radiation can enhance TGF(Beta) induced EMT; while ATM is triggering the process of TGF(Beta)-induced EMT, p53 might be an essential repressor for EMT phenotypes.

Wang, Minli↗
NASA NTRS2012

Dual-Doppler Feasibility Study

When two or more Doppler weather radar systems are monitoring the same region, the Doppler velocities can be combined to form a three-dimensional (3-D) wind vector field thus providing for a more intuitive analysis of the wind field. A real-time display of the 3-D winds can assist forecasters in predicting the onset of convection and severe weather. The data can also be used to initialize local numerical weather prediction models. Two operational Doppler Radar systems are in the vicinity of Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS); these systems are operated by the 45th Space Wing (45 SW) and the National Weather Service Melbourne, Fla. (NWS MLB). Dual-Doppler applications were considered by the 45 SW in choosing the site for the new radar. Accordingly, the 45th Weather Squadron (45 WS), NWS MLB and the National Aeronautics and Space Administration tasked the Applied Meteorology Unit (AMU) to investigate the feasibility of establishing dual-Doppler capability using the two existing systems. This study investigated technical, hardware, and software requirements necessary to enable the establishment of a dual-Doppler capability. Review of the available literature pertaining to the dual-Doppler technique and consultation with experts revealed that the physical locations and resulting beam crossing angles of the 45 SW and NWS MLB radars make them ideally suited for a dual-Doppler capability. The dual-Doppler equations were derived to facilitate complete understanding of dual-Doppler synthesis; to determine the technical information requirements; and to determine the components of wind velocity from the equation of continuity and radial velocity data collected by the two Doppler radars. Analysis confirmed the suitability of the existing systems to provide the desired capability. In addition, it is possible that both 45 SW radar data and Terminal Doppler Weather Radar data from Orlando International Airport could be used to alleviate any radar geometry issues at the NWS MLB radar, such as the "cone of silence" or beam blockage. In the event of a radar outage at one of the sites, the multi-radar algorithms would provide continuing coverage of the area through use of the data from the remaining operational radar sites. There are several options to collect, edit, synthesize and display dual-Doppler data sets. These options include commercial packages available for purchase and a variety of freeware packages available from the National Center for Atmospheric Research (NCAR) for processing raw radar data. However, evaluation of the freeware packages revealed that they do not have sufficient documentation and configuration control to be certified for 45 SW use. Additionally, a TI data line must be installed/leased from the NWS MLB office and CCAFS to enable the receipt of NWS MLB raw radar data to use in the dual-Doppler synthesis. Integration of the TI data line into the Eastern Range infrastructure that will meet the security requirements necessary for 45 SW use is time-consuming and costly. Overall evaluation indicates that establishment of the dual-Doppler capability using the existing operational radar systems is desirable and feasible with no technical concerns. Installation of such a system represents a significant enhancement to forecasting capabilities at the 45 WS and at NWS MLB. However, data security and cost considerations must be evaluated in light of current budgetary constraints. In any case, gaining the dual-Doppler capability will provide opportunities for better visualization of the wind field and better forecasting of the onset of convection and severe weather events to support space launch operations at KSC and CCAFS.

Huddleston, Lisa L.↗
NASA NTRS2019

The Role of Gravity Mechanotransduction in Regulating Stem Cell Tissue Regenerative Potential at the Single Cell Expressome Level

Gravity is an omnipresent force on Earth, and all living organisms have evolved under the influence of constant gravity. Mechanical forces generated by gravity are potent modulators of stem cell based tissue regenerative mechanisms, inducing cell fate decisions and tissue specific commitment. A novel mechanical unloading investigation assessed the formation, morphology, and gene expression of embryoid bodies (EB), a transitory cell model of early differentiation. After 15 days of spaceflight, the mechanotransduction-null EB cells showed upregulated proliferative mechanisms while differentiation cues were silenced.

Juran, Cassandra M.↗
NASA NTRS2018

Initial Developments Toward an Active Noise Control System for Small Unmanned Aerial Systems

Small unmanned aerial systems have the potential to expand commercial markets from package delivery to infrastructure inspection. Many missions, however, require the vehicles to operate in close proximity to people, where community noise concerns could ultimately limit vehicle acceptability. Therefore, noise control technologies may be needed to achieve an acceptable noise signature and enable widespread use of these vehicles. The purpose of this paper is to assess the feasibility of using loudspeakers attached to the vehicle to actively reduce noise. More specifically, this initial study explores the possibility of using a single loudspeaker to reduce the noise from an isolated rotor. Tests performed in an anechoic chamber with a 7.6 cm diameter speaker and 23.9 cm diameter rotor are used to demonstrate the potential benefits and limitations of the concept. Results confirm that active noise control can work in this application with measured tonal reductions of over 30 dB in specific directions. However, since the radiation characteristics of the speaker are different than the rotor, amplification is observed in other directions. This technology has the potential to create a “cone of silence”, which could be steered during flight operations to minimize the impact on noise sensitive areas.

Schiller, Noah H.↗
NASA NTRSDate not supplied

Quiet Spacecraft Cabin Ventilation Fan Development: Motivation and Context

It is important to control acoustical noise aboard crewed space vehicles and space habitats to provide a satisfactory environment for voice communications, alarm audibility, and restful sleep, and to minimize the risk for hearing loss and annoyance. As with most noise control efforts, it is best to control the noise at the source, and for spaceflight vehicles these are typically the fans associated with the Environmental Control and Life Support (ECLS) system. These include air ventilation fans, such as the main air conditioning fan (the ‘cabin fan’), intermodule ventilation (IMV) fans, air revitalization fans (for removal of carbon dioxide and trace contaminates), and thermal cooling fans. Thermal cooling pumps that circulate cooling fluid are another significant noise source in spaceflight vehicles, but these are outside of the scope of this paper. Throughout the history of crewed spaceflight, there have been issues with noise from ECLS ventilation fans. In the Apollo Command Module (CM) the crew would turn off the CM cabin fan once in orbit and use the backup suit-loop fan for ventilation because noise from the cabin fan interfered with communications and was an annoyance. On the Space Shuttle the ventilation system underwent significant redesign, including the addition of ventilation system mufflers, with resulting noise levels that were still too-high for long-duration missions. In the early years of International Space Station (ISS) operations, acoustical noise was one of the top two habitability issues, resulting in significant noise controls (along with significant cost and crew-time impacts) being implemented on-orbit on many fans, with significant noise reductions realized only after replacing noisy fans with fans of a quieter design, funded by the ISS Program. And, with the spaceflight vehicles and habitats currently being developed, there are again concerns with noise levels from ventilation fans. In the Orion vehicle, additional duct mufflers needed to be added to address the cabin fan noise. The Gateway’s Habitation and Logistics Outpost (HALO) module and low-Earth orbit (LEO) Freeflyer habitats are currently working to solve this problem. This will also be an issue for lunar and Mars spaceflight vehicles, space suits, and surface habitats. In an effort to address this problem, NASA is working to leverage the technology developed in its Aeronautics Research Mission Directorate (ARMD), specifically at the Glenn Research Center (GRC), to design highly efficient and quiet fans for reducing community noise levels from civilian aircraft. This technology was created over decades of research and development, and was proven to be effective at reducing aircraft noise levels. The current collaboration across NASA Centers, including HQ, GRC, and the Johnson Space Center (JSC) in this area is the first effort at re-purposing these tools, i.e. design codes and techniques, developed for high Reynolds number fans to spaceflight vehicle and habitat, low Reynolds number, fans. This paper will discuss the need for transfer of aeronautics fan design technology to spaceflight use. This paper will also discuss the potential benefits from this, which are significant, including 1) volume and mass savings from noise controls that are no longer as large or needed at all, 2) reduced system pressure loss from mufflers and silencers (that don’t need to be as restrictive) for better ventilation, 3) reduced power draw because of the reduced system pressure loss and the highly efficient fan design, and 4) satisfying spaceflight vehicle acoustic requirements to provide a safe and habitable acoustic environment for astronaut crewmembers. All of these benefits will be crucial for the successful development and operations of future spaceflight vehicles, space suits, and habitats.

Christopher S. Allen↗
NASA NTRSDate not supplied

Speech-Enhanced and Context Dependent Alerts: Future Implications for Spacecraft Design Abstract

In the future, NASA missions will involve many different space vehicles, habitats, and surface assets working together to provide safe and productive living and working environments for crew. Because these systems will be provided by multiple commercial companies working with NASA, it will be very different from missions of the past, bringing new challenges. One of the challenges is related to whether NASA should move beyond simple tone annunciation alerting systems, to more advanced systems that include speech. The other is related to determining the level of consistency required of safety-critical alert systems across spacecraft. Two studies were completed to address these important issues. The first study investigated the advantages and disadvantages of a tone+speech alert relative to the traditional tone-only alert. Results indicate that speech-enhanced alerts initially take longer to silence (the default action to which NASA personnel are trained), due to the need to listen to the entire message, but ultimately provided for faster understanding of the alert situation. Speech-enhanced alerts were also preferred by a large majority of crew-like study participants. An unexpected finding from this first study was that participants took longer to respond to tone-only alerts when they were mixed with speech- enhanced alerts. Participants waited to hear the speech message even for alerts they were trained to know did not contain speech components. This performance error is believed to be due to negative transfer of training. A second study focused on task and alert performance using a common set of tones across two contexts (“vehicles”) versus performance with a different set of tones for each context (“vehicle”). Participants were able to manage two different alert sets successfully; results indicate that discriminability of the two alert sets played a major role in their success. Implications for the design of spacecraft alerts are discussed and future areas of research are identified.

alerts↗
NASA NTRS2023

Speech-Enhanced and Context Dependent Alerts: Future Implications for Spacecraft Design

In the future, NASA missions will involve many different space vehicles, habitats, and surface assets working together to provide safe, productive environments for crew. Because these systems will be provided by multiple commercial companies working with NASA, it will be very different from missions of the past, bringing new challenges. One of the challenges is related to whether NASA should move beyond simple tone annunciation alerting systems, to more advanced systems that include speech. The other is related to determining the level of consistency required of safety-critical alert systems across spacecraft. Two studies were completed to address these important issues. The first study investigated the advantages and disadvantages of a tone+speech alert relative to the traditional tone-only alert. Results indicate that speech-enhanced alerts initially take longer to silence (the default action to which NASA personnel are trained), due to the need to listen to the entire message, but ultimately provided for faster understanding of the alert situation. Speech-enhanced alerts were also preferred by a large majority of crew-like study participants. An unexpected finding was that participants took longer to respond to tone-only alerts that were heard in the same session as speech-enhanced alerts. Participants waited to hear a speech message even for alerts they were trained to know did not contain speech components. This performance error is believed to be due to negative transfer of training. A second study focused on task and alert performance using a common set of tones across two contexts (e.g., vehicles, habitats, suits) versus performance with a different set of tones for each context. Participants were able to manage two different alert sets successfully; results indicate that discriminability of the two alert sets played a major role in their success. Implications for the design of spacecraft alerts are discussed, and future areas of research are identified.

alerts↗
NASA NTRS2023

Uncovering Unique Molecular Adaptations in the Arabidopsis Thaliana Cvi-0 Ecotype

This research proposal aims to investigate the unique molecular adaptations exhibited by Arabidopsis Thaliana, specifically focusing on the Cape Verde Islands (Cvi-0) ecotype, in response to microgravity conditions. The study examines data from NASA’s Open Science Data Repository and applies a multifaceted RNAseq analysis pipeline using tools in the UseGalaxy.org open platform. Through transcriptomic analysis, differential gene expression patterns were identified in Cvi-0, revealing an absence of heat shock protein (HSP) upregulation and an upregulation of Rubisco Activase (RCA) and chloroplast-related pathways. To test the hypothesis that these adaptations may contribute to Cvi-0’s increased adaptability in microgravity, a three-fold experimental design is proposed. Four experimental groups will be cultivated under simulated microgravity and ground control conditions, including Cvi-0, Col-0, and genetically modified Col-0 with silenced HSP genes, and genetically modified Col-0 with upregulated RCA gene. Growth parameters will be measured to assess plant resilience, and RNA sequencing will provide transcriptomic data for pathway analysis. Anticipated outcomes include improved markers of plant health (mass, growth, etc.) of Cvi-0 in simulated microgravity and enhanced resilience in genetically altered Col-0 variants, providing insights into potential mechanisms of adaptation. This research would bear significance for space agriculture, nutrition for extended space missions, and sustainable terrestrial crop enhancement. Moreover, the insights gained could reshape crop engineering on Earth, enhancing robustness to climate induced stresses and bolstering global food security. The proposal’s trajectory blends scientific curiosity with practical applicability, forging a path towards sustainable food production and improving human exploration beyond our planet.

GL4HS↗
NASA NTRSDate not supplied

Investigating the Relationship between the Cell Wall Integrity Pathway and Unfolded Protein Response

Plants have made significant contributions to astronaut health in spaceflight missions. To further spaceflight research in optimizing plant viability, this study aims to understand the factors involved in maintaining cell wall integrity, which is vital to plant morphology and structural stability. Spaceflight can negatively impact the cell wall; thus, it is crucial to investigate how to mitigate spaceflight stressors to maintain the integrity of the cell wall. The structural integrity of plants’ cell walls depends on secondary cell wall biogenesis, which enables the repair and architectural support of plants like A. thaliana. This biogenesis is triggered by a signal transduction cascade: first initiated by cell wall stress, the CWI (cell wall integrity) pathway is activated, followed by the UPR (unfolded protein response), then the cell wall’s integrity is maintained through secondary cell wall biogenesis. Through a re-analysis of GeneLab Dataset 321 (GLDS-321), a study from NASA’s Open Science Data Repository that investigates the effects of spaceflight on the UPR, several genes were found to be associated with the cell wall. This proposal postulates a relationship between the UPR and the CWI pathway and their direct effect on secondary cell wall biogenesis by investigating IRX7, a gene associated with secondary cell wall biogenesis. The predicted outcome of overexpressing IRX7 is increased resilience of the cell wall by upregulating both the UPR and the CWI pathway, while silencing IRX7 is predicted to compromise the cell wall integrity by downregulating the UPR and the CWI pathway. This study will give insight into the needed measures to increase cell wall resilience in stressful environments: As spaceflight durations increase and uncertain climate change events progress on Earth, understanding how to optimize cell wall resilience – a fundamental pillar of plant health – can effectively enhance mass crop production and quality and ensure the physical and psychological health of astronauts in long-term space missions.

GL4HS↗
NASA NTRS2023

T-Cell Shenanigans: The Impact of MHC Pathway & Lipid Metabolism Genes on T-Cell Differentiation in the Thymus

Astronaut health and proper immune function are key to the success and sustainability of long term missions in space. While previous studies have observed adaptive immune dysfunction such as diminished WBC counts and cytokine production during spaceflight, the underlying mechanisms behind why immune function worsens are poorly understood. Using transcriptomic data analyzed from mouse thymus tissues available from the GLDS-421 experiment on the Rodent Research-9 mission, we used the GeneLab standardized RNA-Seq pipeline and identified four genes that were largely dysregulated (p<0.05): lipid metabolic genes Hpgd and Pgr and cell cycle regulator genes Cenpe and Kif11. We analyzed how these genes regulate the MHC-TCR interaction, and used this understanding to propose a novel mechanism for alterations to T-cell differentiation. In our experimental methodology, we propose to use 36 transgenic CD4-CD8 mice and 12 wild-type mice from the Jackson Lab to create a microgravity-simulating hindlimb unloading model and test our hypothesis. By silencing the aforementioned genes using custom siRNA based primers, we will use flow cytometry and RNA-Seq to quantify Treg counts in comparison to naive CD4+ cells, Alamar Blue assay for observing the metabolic activity in T-cells, and Enzyme-Linked Immunosorbent Assay (ELISA) to observe the general immune response in terms of T-cell differentiation. We hope this methodology will improve our knowledge of MHC-TCR interaction, contribute to a better understanding of the mechanisms of autoimmune diseases such as lupus, and improve the success rate of newer cancer treatments such as CAR-T cell therapy.

GL4HS↗