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We examine time series of OCO-2 xCO2 observations from 2017-2020 coincident with other remotely sensed and in-situ observations to better understand external sampling effects associated with biomass burning events. The GES DISC will publish How-To documents as Jupyter Notebooks to describe how to aggregate OCO-2 Level 2 data and create similar time series.
In this presentation we will provide basic radiation effects on electronics, information on radiation effects and sources, a review of domestic SEE facilities and other radiation test facilities.
Heavy secondary ions do not significantly alter device responses. Conclusion that external reaction products cause no significant alteration of single-event-upset response based on comparison of data obtained from both lidded and unlidded devices and for proton beams impinging at angles ranging from 0 degrees to 180 degrees with respect to chip face. Study also found single-event-upset cross section increases only modestly as proton energy increased to 590 MeV, characteristic of maximum energies expected in belts of trapped protons surrounding Earth and Jupiter.
The results of photographic and video surveys conducted on the Mir space station are reported. The observations were performed in order to quantitatively and qualitatively assess the effects of the external deposition and contamination, surface degradation, dynamic events, and micrometeoroid and orbital debris impacts. The lessons learned from Mir imagery observations can be applied to the International Space Station program. The photographic and video data confirm the general good condition of the external surfaces of Mir.
An instrument that receives pulses from a primary external source and one or more secondary external sources and determines when there is coincidence between the primary and one of the secondary sources is described. The instrument generates a finite time window (coincidence aperture) during which coincidence is defined to have occurred. The time intervals between coincidence apertures in which coincidences occur are measured.
Results are presented from fragmentation experiments at elevated external pressure; the application of overpressure to a small target allows the experiment to match the lithospheric compressive stress of a larger body's interior. With increasing overpressure, the fragmentation undergoes a transition, from a material strength-dominated regime to one that is dominated by applied overpressure, analogous to the transition from strength to gravity effects. High pressure testing allows direct measurement of the energy/unit target mass requirement of catastrophic fragmentation due to compressive stresses.
To investigate the use of audio signals as a simple, noninvasive measure of emetic activity, the relationship between the somatic events and sounds associated with retching and vomiting was studied. Thoracic venous pressure obtained from an implanted external jugular catheter was shown to provide a precise measure of the somatic events associated with retching and vomiting. Changes in thoracic venous pressure monitored through an indwelling external jugular catheter with audio signals, obtained from a microphone located above the animal in a test chamber, were compared. In addition, two independent observers visually monitored emetic episodes. Retching and vomiting were induced by injection of xylazine (0.66mg/kg s.c.), or by motion. A unique audio signal at a frequency of approximately 250 Hz is produced at the time of the negative thoracic venous pressure change associated with retching. Sounds with higher frequencies (around 2500 Hz) occur in conjunction with the positive pressure changes associated with vomiting. These specific signals could be discriminated reliably by individuals reviewing the audio recordings of the sessions. Retching and those emetic episodes associated with positive venous pressure changes were detected accurately by audio monitoring, with 90 percent of retches and 100 percent of emetic episodes correctly identified. Retching was detected more accurately (p is less than .05) by audio monitoring than by direct visual observation. However, with visual observation a few incidents in which stomach contents were expelled in the absence of positive pressure changes or detectable sounds were identified. These data suggest that in emetic situations, the expulsion of stomach contents may be accomplished by more than one neuromuscular system and that audio signals can be used to detect emetic episodes associated with thoracic venous pressure changes.
Shoulder Postures in EVA Training in Reduced Gravity Analogues K. Guhl1, L. Vu2, H. Kim3, S. Rajulu4 1KBR Inc., Houston, TX, 2Aegis Aerospace Inc., Houston, TX, 3Leidos Innovations, Houston, TX, 4NASA Johnson Space Center, Houston, TX. During extravehicular activities (EVAs) and EVA training in both the Neutral Buoyancy Laboratory (NBL) and at the Active Response Gravity Offload System (ARGOS), crewmembers perform a variety of hand-intensive tasks with frequent arm/shoulder repositioning while wearing a pressurized spacesuit. As a result, crewmembers may experience ergonomic stressors such as awkward shoulder postures. The ergonomic shoulder risk is also compounded by limited or restricted shoulder mobility of the spacesuit, extreme work positions such as overhead tasks, and tasks with heavy tools and repetitive motions. Prolonged or frequent shoulder elevation and overhead work, in particular, can lead to excessive stresses and musculoskeletal injuries of the shoulder joints. Future EVA missions, specifically lunar surface EVAs, will also be longer in duration and thus increase the exposure to awkward shoulder postures. In this study, we aimed to assess the ergonomic risk of awkward shoulder postures in simulated lunar surface EVAs by quantifying when and how long the arms are raised above the chest level. We assessed video recordings of pilot lunar EVA simulations (3 lunar trials each in the NBL and at ARGOS and 2 microgravity EVA trials in the NBL). These runs consisted of both training and engineering test objectives. Actual demands for shoulder use varied for different EVA types and analogues, but many EVA runs have common tasks and require similar motion components. A video observation and event logging software was used to document the duration and occurrence of the subject’s arms being raised throughout the video recordings of each EVA run. An arm raised instance was classified as the arm being at 90 degrees or above with relation to gravity for lunar EVA training events and with relation to the body for microgravity EVA training events. Such events included EVA hardware maintenance or heavy geology sampling tool operations. Events where the arm load was partially supported by external objects, like climbing a ladder or leaning against a surface were separately identified and excluded. Statistical analysis was performed to summarize the timing, frequency, and durations of the arm raise events and compared across the different EVA tasks and analogue types. Preliminary observations indicated that the total duration and number of arm raised instances were surprisingly smaller for lunar surface EVA training as compared to microgravity EVA training. The observed difference may be attributed to differing task demands and unique environmental characteristics found in lunar EVAs in comparison to microgravity EVAs. A detailed statistical analysis will be performed between lunar surface EVA training events and microgravity EVA training events in the final submission. Overall, this analysis is expected to provide insight into how ergonomic recommendations can be refined for lunar EVA training with pressurized suits. It may also inform task design and influence suit padding design to better protect crewmembers during future lunar training.
The ISS External Survey integrates the requirements for photographic and video imagery of the International Space Station (ISS) for the engineering, operations, and science communities. An extensive photographic survey was performed on all Space Shuttle flights to the ISS and continues to be performed daily, though on a level much reduced by the limited available imagery. The acquired video and photo imagery is used for both qualitative and quantitative assessments of external deposition and contamination, surface degradation, dynamic events, and MMOD strikes. Many of these assessments provide important information about ISS surfaces and structural integrity as the ISS ages. The imagery is also used to assess and verify the physical configuration of ISS structure, appendages, and components.
This 2023-2024 report provides a comprehensive summary of the products and activities executed by the NASA Agile Community of Practice over its first year from being formally stood up. The report highlights the community's ongoing efforts to advance Agile values and principles, improve practices, and foster innovation within teams across NASA centers. The report delves into key initiatives, including the development of a strategic plan, executive summary, and best practice guidelines; as well as the facilitation of knowledge-sharing events such as webinars with internal and external speakers, workshops, and technical interchange meeting.
A synchronous parallel system for emulation and discrete event simulation having parallel nodes responds to received messages at each node by generating event objects having individual time stamps, stores only the changes to state variables of the simulation object attributable to the event object, and produces corresponding messages. The system refrains from transmitting the messages and changing the state variables while it determines whether the changes are superseded, and then stores the unchanged state variables in the event object for later restoral to the simulation object if called for. This determination preferably includes sensing the time stamp of each new event object and determining which new event object has the earliest time stamp as the local event horizon, determining the earliest local event horizon of the nodes as the global event horizon, and ignoring the events whose time stamps are less than the global event horizon. Host processing between the system and external terminals enables such a terminal to query, monitor, command or participate with a simulation object during the simulation process.
This paper presents a description of a microcomputer based software package, called DYNAMAN, which has been developed to allow an analyst to simulate the dynamics of a system consisting of a number of mass segments linked by joints. One primary application is in predicting the motion of a human occupant in a vehicle under the influence of a variety of external forces, specially those generated during a crash event. Extensive use of a graphical user interface has been made to aid the user in setting up the input data for the simulation and in viewing the results from the simulation. Among its many applications, it has been successfully used in the prototype design of a moving seat that aids in occupant protection during a crash, by aircraft designers in evaluating occupant injury in airplane crashes, and by users in accident reconstruction for reconstructing the motion of the occupant and correlating the impacts with observed injuries.
A synchronous parallel system for emulation and discrete event simulation having parallel nodes responds to received messages at each node by generating event objects having individual time stamps, stores only the changes to the state variables of the simulation object attributable to the event object and produces corresponding messages. The system refrains from transmitting the messages and changing the state variables while it determines whether the changes are superseded, and then stores the unchanged state variables in the event object for later restoral to the simulation object if called for. This determination preferably includes sensing the time stamp of each new event object and determining which new event object has the earliest time stamp as the local event horizon, determining the earliest local event horizon of the nodes as the global event horizon, and ignoring events whose time stamps are less than the global event horizon. Host processing between the system and external terminals enables such a terminal to query, monitor, command or participate with a simulation object during the simulation process.
The Integrated Medical Model (IMM) is a probabilistic tool, used in mission planning decision making and medical systems risk assessments. The IMM project maintains a database of over 80 medical conditions that could occur during a spaceflight, documenting an incidence rate and end case scenarios for each. In some cases, where observational data are insufficient to adequately define the inflight medical risk, the IMM utilizes external probabilistic modules to model and estimate the event likelihoods. One such medical event of interest is an unpassed renal stone. Due to a high salt diet and high concentrations of calcium in the blood (due to bone depletion caused by unloading in the microgravity environment) astronauts are at a considerable elevated risk for developing renal calculi (nephrolithiasis) while in space. Lack of observed incidences of nephrolithiasis has led HRP to initiate the development of the Renal Stone Formation Module (RSFM) to create a probabilistic simulator capable of estimating the likelihood of symptomatic renal stone presentation in astronauts on exploration missions. The model consists of two major parts. The first is the probabilistic component, which utilizes probability distributions to assess the range of urine electrolyte parameters and a multivariate regression to transform estimated crystal density and size distributions to the likelihood of the presentation of nephrolithiasis symptoms. The second is a deterministic physical and chemical model of renal stone growth in the kidney developed by Kassemi et al. The probabilistic component of the renal stone model couples the input probability distributions describing the urine chemistry, astronaut physiology, and system parameters with the physical and chemical outputs and inputs to the deterministic stone growth model. These two parts of the model are necessary to capture the uncertainty in the likelihood estimate. The model will be driven by Monte Carlo simulations, continuously randomly sampling the probability distributions of the electrolyte concentrations and system parameters that are inputs into the deterministic model. The total urine chemistry concentrations are used to determine the urine chemistry activity using the Joint Expert Speciation System (JESS), a biochemistry model. Information used from JESS is then fed into the deterministic growth model. Outputs from JESS and the deterministic model are passed back to the probabilistic model where a multivariate regression is used to assess the likelihood of a stone forming and the likelihood of a stone requiring clinical intervention. The parameters used to determine to quantify these risks include: relative supersaturation (RS) of calcium oxalate, citrate/calcium ratio, crystal number density, total urine volume, pH, magnesium excretion, maximum stone width, and ureteral location. Methods and Validation: The RSFM is designed to perform a Monte Carlo simulation to generate probability distributions of clinically significant renal stones, as well as provide an associated uncertainty in the estimate. Initially, early versions will be used to test integration of the components and assess component validation and verification (V&V), with later versions used to address questions regarding design reference mission scenarios. Once integrated with the deterministic component, the credibility assessment of the integrated model will follow NASA STD 7009 requirements.
The International Space Station is the largest and most complex on-orbit platform for space science utilization in low Earth orbit. The Space Environments Team addresses natural and induced environments for the ISS Program including external contamination, ionizing radiation, neutral atmosphere and solar ultraviolet radiation, plasma effects, and acoustics. For the ISS to fulfill its mission as a long-duration science platform, space environments effects are assessed, monitored, and controlled through design or operational mitigation. Interactions of ISS hardware with the natural and induced space environments, and the assessment and mitigation of those effects play a critical role in ISS mission operations. The Space Environments Team has complete system integration responsibility in these area for U.S./International Partner/Russian hardware, visiting vehicles, ISS payloads and operation. Lessons learned and processes developed for ISS are applicable to the design, assembly, and operations of long-duration space systems.
This paper describes the concept of a large gamma-ray imaging telescope system (GRITS) which will provide sufficient sensitivity for the identification of faint objects to be catalogued by the Gamma-Ray Observatory. The technique used in this telescope for the detection of gamma rays is based on the conversion of the incident gamma ray into an electron-positron pair which subsequently produces Cherenkov radiation. The gamma ray is identified by a unique signature based on a sequence of time-delayed coincidence events. The GRITS telescope will use the extended Shuttle external tank, ET, as the pressure vessel necessary for the gas-Cherenkov process. Astronauts from the Shuttle or the Space Station performing EVA will convert ET to an autonomous spacecraft and install the telescope inside the ET.
A printed circuit board which will provide external clocks and precisely measure the time at which events take place was designed for the Bristol University Gas Spectrometer (BUGS). The board, which was designed to interface both mechanically and electrically to the Computer Automated Measurement and Control (CAMAC) system, has been named the BUGS system clock control. The board's design and use are described.
The Neutral Buoyancy Laboratory (NBL) is a 102 x 202 x 40-foot-deep tank holding over 6 million gallons of water used to simulate weightlessness for Astronaut training. The maxim "Train Like You Fly" refers to the desire to have the suit perform, during training, as close as possible to how it performs during an Extra-Vehicular Activity (EVA), particularly with respect to mobility. Therefore, the Space Suit Assembly (SSA) used in the NBL is a downgraded hardware version of the flight SSA; it is not designed for the NBL environment or operations. A classification system defines the flight Space Suit Assembly hardware as Class I, and the NBL training hardware SSA as Class IIIW. On July 20, 2017, during a manned training event in the NBL, the SSA was inadvertently over-pressurized to 22 psid; normal operating pressure being 4.3 psid. The suit subject was removed from the suit with no injury. The event was investigated by a NASA Mishap Team. The Team investigated common causes and differences between the Class I and Class IIIW Extra-vehicular Mobility Unit (EMU). The investigation determined that the event was limited to Class IIIW hardware and its external flow-controlled open loop ventilation systems. The flight EMU is a pressure regulated closed loop ventilation system. This paper will examine the differences between the Class I and Class IIIW SSA hardware and provide details of the Mishap Investigation. Corrective actions taken to mitigate risk with hardware, operations, and hazard documentation will be discussed.