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NASA NTRS2014

Veggie Hardware Validation Test Preliminary Results and Lessons Learned

The Veggie hardware validation test, VEG-01, was conducted on the International Space Station during Expeditions 39 and 40 from May through June of 2014. The Veggie hardware and the VEG-01 experiment payload were launched to station aboard the SpaceX-3 resupply mission in April, 2014. Veggie was installed in an Expedite-the-Processing-of-Experiments-to-Space-Station (ExPRESS) rack in the Columbus module, and the VEG-01 validation test was initiated. Veggie installation was successful, and power was supplied to the unit. The hardware was programmed and the root mat reservoir and plant pillows were installed without issue. As expected, a small amount of growth media was observed in the sealed bags which enclosed the plant pillows when they were destowed. Astronaut Steve Swanson used the wet/dry vacuum to clean up the escaped particles. Water insertion or priming the first plant pillow was unsuccessful as an issue prevented water movement through the quick disconnect. All subsequent pillows were successfully primed, and the initial pillow was replaced with a backup pillow and successfully primed. Six pillows were primed, but only five pillows had plants which germinated. After about a week and a half it was observed that plants were not growing well and that pillow wicks were dry. This indicated that the reservoir was not supplying sufficient water to the pillows via wicking, and so the team reverted to an operational fix which added water directly to the plant pillows. Direct watering of the pillows led to a recovery in several of the stressed plants; a couple of which did not recover. An important lesson learned involved Veggie's bellows. The bellows tended to float and interfere with operations when opened, so Steve secured them to the baseplate during plant tending operations. Due to the perceived intensity of the LED lights, the crew found it challenging to both work under the lights and read crew procedures on their computer. Although the lights are not a safety hazard, for visual comfort crewmembers were advised to wear sunglasses when working with the plants and then they can lift glasses to read procedures. Steve Swanson had already trail-blazed this procedure when he initiated VEG-01. The temperature and humidity data logger was relocated mid-experiment to provide measurements on both sides of the unit. Images of the plants were downlinked weekly, and videos of installation and harvest were recorded. This imaging frequency was not sufficient to monitor and respond to changes in plant growth. Plants, samples, and data loggers will be returned on SpaceX-4, scheduled to return the fall of 2014. Lessons learned will be translated into hardware and operational modifications for future Veggie payloads.

International Space Station↗

NASA NTRS1974

Skylab: The Second Manned Mission. A Scientific Harvest

Covers the Skylab launch activities and docking with unmanned SL-1 workshop. Includes observations of student experiments (the Minchmog minnows and Arabella, the spider), observations of student experiments, exercise routines, and the enabling of the Earth Resources Experiments Package. Shows planet Earth documentation, manned operation of the Apollo Telescope Mount for observations of the Sun and beyond, outside EVA activity, testing of the Astronaut Maneuvering Unit, experiments to explore industrial uses of space, and the Skylab living routine.

AV Corporation↗

NASA NTRS1997

The Role of GH/IGF-I Axis in Muscle Homeostasis During Weightlessness

Exposure to reduced gravity during space travel profoundly alters the loads placed on bone and muscle. Astronauts suffer significant losses of muscle and bone strength during weightlessness. Exercise as a countermeasure is only partially effective in remedying severe muscle atrophy and bone demineralization. Similar wasting of muscles and bones affects people on Earth during prolonged bed rest or immobilization due to injury. In the absence of weight bearing activity, atrophy occurs primarily in the muscles that act in low power, routine movements and in maintaining posture. Hormonal disfunction could contribute in part to the loss of muscle and bone during spaceflight. Reduced levels of human Growth Hormone (hGH) were found in astronauts during space flight, as well as reduced GH secretory activity was observed from the anterior pituitary in 7-day space flight rats. Growth hormone has been shown to be required for maintenance of muscle mass and bone mineralization, in part by mediating the biosynthesis IGF-I, a small polypeptide growth factor. IGF biosynthesis and secretion plays an important role in potentiating muscle cell differentiation and has been shown to drive the expression of myogenin, a myogenic specific basic helix-loop-helix factor. IGF-I has also been shown to have an important role in potentiating muscle regeneration, repair and adult muscle hypertrophy.

Schwartz, Robert J.↗

NASA NTRSDate not supplied

How Do Humans Sleep in Space?

This presentation reviews what is known about how humans sleep in space. It covers historical studies that showed that humans only sleep ~6 hours a night in space and how circadian misalignment influences sleep and hypnotic use. It also covers more recent studies that show that environment and scheduling are responsible for much of the previously observed sleep disruption. The presentation also discusses how sleep architecture may be different in space compared to on Earth along with the possible reasons for observed differences.

sleep↗

NASA NTRS2013

Probabilistic Modeling of the Renal Stone Formation Module

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.

kidney stones↗

NASA NTRS2020

Temporal Changes in Astronauts’ Muscle and Cardiorespiratory Physiology Pre-, In-, and Post-Spaceflight

NASA’s vision for future exploration missions depends on the ability to protect astronauts’ health and safety for performance of Extravehicular Activity (EVA), and to allow astronauts to safely egress from vehicles in a variety of landing scenarios (e.g. water landing upon return to Earth and undefined planetary/lunar landings). Prolonged exposure to spaceflight results in diminished tolerance to prolonged physical activity, decreased cardiac and sensorimotor function, and loss of bone mineral density, muscle mass, and muscle strength. For over 50 years exercise has been the primary countermeasure against these physiologic decrements during spaceflight, and while the resulting protection is adequate for ISS missions (i.e., Soyuz landing, microgravity EVAs), there is little information regarding time-course changes in muscle and aerobic performance. As spaceflight progresses towards longer exploration missions and vehicles with less robust exercise capabilities compared to ISS, countermeasures will need to be combined and optimized to protect crew health and performance across all organ systems over the course of exploration missions up to 3 years in duration. This will require a more detailed understanding of the dynamic effects of spaceflight on human performance. Thus, the focus of this study is quantifying decrements in physical performance over different mission durations, and to provide detailed information on the physiological rational for “why” and “when” observed changes in performance occur. The research proposed will temporally profile changes in astronauts’ cardiorespiratory fitness, muscle mass, strength, and endurance over spaceflight missions of 2 months, 6 months, and up to 1 year in duration. Additionally, an extrapolation model will provide predictions for changes associated with exploration missions 2-3 years in duration. To accomplish these objectives astronauts will be asked to participate in pre, in, post-flight measurement of muscle performance, muscle size, cardiorespiratory fitness and submaximal performance capabilities, as well as non-invasive assessment of cerebral and muscle oxygenation and perfusion (Table 1). Additionally, ambulatory and in-flight exercise, nutrition, and sleep will be monitored using a variety of commercial technologies and in-flight assessment tools. Significance: Our detailed testing protocol will provide valuable information for describing how and when spaceflight-induced muscle and aerobic based adaptations occur over the course of spaceflight missions up to and beyond 1 year. This information will be vital in the assessment as to whether humans can be physically ready for deep space exploration such as Mars missions with current technology, or if additional mitigation strategies are necessary.

Downs, M. E.↗

NASA NTRS1992

Cardiovascular orthostatic function of Space Shuttle astronauts during and after return from orbit

Routine entry, landing, and seat egress after Space Shuttle flights is observed to be associated with drops in blood pressure and increases in heart rate that indicate that the cardiovascular system is performing at its maximum capacity in a large fraction (30 percent) of the study population. It is not apparent that adequate cardiovascular reserve capacity remains to accommodate unaided emergency egress after either current or extended space flights.

Charles, John B.↗

NASA NTRS1994

International mission planning for space Very Long Baseline Interferometry

Two spacecraft dedicated to Very Long Baseline Interferometry (VLBI) will be launched in 1996 and 1997 to make observations using baselines between the space telescopes and many of the world's ground radio telescopes. The Japanese Institute of Space and Astronautical Science (ISAS) will launch VSOP (VLBI Space Observatory Program) in September 1996, while the Russian Astro Space Center (ASC) is scheduled to launch RadioAstron in 1997. Both spacecraft will observe radio sources at frequencies near 1.7, 4.8, and 22 GHz; RadioAstron will also observe at 0.33 GHz. The baselines between space and ground telescopes will provide 3-10 times the resolution available for ground VLBI at the same observing frequencies. Ground tracking stations on four continents will supply the required precise frequency reference to each spacecraft measure the two-way residual phase and Doppler on the ground-space link, and record 128 Megabit/s of VLBI data downlinked from the spacecraft. The spacecraft data are meaningless without cross-correlation against the data from Earth-bound telescopes, which must take place at special-purpose VLBI correlation facilities. Therefore, participation by most of the world's radio observatories is needed to achieve substantial science return from VSOP and RadioAstron. The collaboration of several major space agencies and the ground observatories, which generally follow very different models for allocation of observing time and for routine operations, leads to great complexity in mission planning and in day-to-day operations. This paper describes some of those complications and the strategies being developed to assure productive scientific missions.

Ulvestad, James S.↗

NASA NTRS2011

Surveillance of Ocular Parameters and Visual Function in Bed Rest Subjects

Recent visual changes in astronauts have raised concern about ocular health during long duration spaceflight. Seven cases have been documented in astronauts who spent 6 months aboard the International Space Station. These astronauts were male ranging in age from 45 to 55 years old. All astronauts exhibited pre- to post flight refractive changes. Decreased intraocular pressure (IOP) post flight was observed in 3 cases. Fundoscopic exams revealed post flight findings of choroidal folds in 4 cases, optic disc edema in 5 cases and the presence of cotton wool spots in 3 cases. Optical coherence tomography (OCT) confirmed findings of choroidal folds and disc edema, and also documented retinal nerve fiber layer thickening (5 cases). Findings from MRI examinations showed posterior globe flattening (5 cases), optic nerve sheath distention (6 cases) and torturous optic nerves (2 cases). Of the 7 cases, intracranial pressure was measured on 4 astronauts. These 4 showed elevated ICP post-flight that remained elevated for as long as 19 months in one case. While the etiology remains unknown, hypotheses speculate that venous insufficiency or hypertension in the brain caused by cephalad fluid shifts during spaceflight are possible mechanisms for ocular changes seen in astronauts. Head-down tilt bed rest is a spaceflight analog that induces cephalad fluid shifts. This study is designed to provide ocular monitoring of bed rest subjects and determine whether clinically relevant changes are found. Ocular Changes

Cromwell, Ronita L.↗

NASA NTRS2011

Increased Intracranial Pressure and Visual Impairment Associated with Long-Duration Spaceflight

Although humans have been flying in space since the 1960s, more recent missions have revealed a new suite of physiological adaptations and consequences of space flight. Notably, 60% of long-duration crewmembers (ISS/MIR) and >25% of short-duration (Shuttle) crewmembers have reported subjective degradation in vision (based on debrief comments) (Gibson 2011). Decreased near-visual acuity was demonstrated in 46% of ISS/Mir and 21% of Shuttle crewmembers, resulting in a shift of up to 1-2 diopters in their refractive correction. It is likely that the recently revealed ophthalmic changes have been present since the first days of human space flight, but have been overlooked or attributed to other causations. The reported changes in vision have occurred at various time points throughout missions, with ranging degrees of visual degradation. Although some cases resolved upon return to Earth, several astronauts have not regained preflight visual acuity, indicating that the damage may be permanent. While observing these changes over the years, without other overt symptomology and with the given age range of the flying population, this has largely been attributed to an expected hyperopic shift due to aging. However, the availability of onboard analysis techniques, including visual acuity assessments, retinal imagery, and ultrasounds of the eye and optic nerve tracts, along with more detailed post-flight techniques, has led to the recent recognition of a wider syndrome. Along with vision changes, findings include flattening of the globe, swelling of the optic disc (papilledema), choroidal folds in the retina, swelling of the optic nerve sheath, and visual field defects. It is widely hypothesized that this constellation of findings may be explained by an elevation of intracranial pressure (ICP). Out of the 60% of long-duration astronauts that have reported a subjective degradation in vision, a subset (currently 10 astronauts) have developed this syndrome. The National Aeronautics and Space Administration (NASA) has made it a high priority to understand this syndrome and provide mitigation techniques to protect crewmembers from visual impairment. While there are many possible factors that could contribute to intracranial hypertension associated with spaceflight, the relative contribution of these, as well as the processes by which eye damage occurs as a result of intracranial hypertension, are not fully understood. The observed pathophysiological phenomena are extremely complex and it is likely that multiple factors contribute to their incidence, rather than one simple mechanism. This paper will define and examine the findings in detail, and expound upon the potential contributing factors and their relative contribution to this syndrome.

Marshall-Bowman, Karina↗

NASA NTRS2017

Astronaut Photography of the Earth: A Long-Term Dataset for Earth Systems Research, Applications, and Education

The NASA Earth observations dataset obtained by humans in orbit using handheld film and digital cameras is freely accessible to the global community through the online searchable database at https://eol.jsc.nasa.gov, and offers a useful compliment to traditional ground-commanded sensor data. The dataset includes imagery from the NASA Mercury (1961) through present-day International Space Station (ISS) programs, and currently totals over 2.6 million individual frames. Geographic coverage of the dataset includes land and oceans areas between approximately 52 degrees North and South latitudes, but is spatially and temporally discontinuous. The photographic dataset includes some significant impediments for immediate research, applied, and educational use: commercial RGB films and camera systems with overlapping bandpasses; use of different focal length lenses, unconstrained look angles, and variable spacecraft altitudes; and no native geolocation information. Such factors led to this dataset being underutilized by the community but recent advances in automated and semi-automated image geolocation, image feature classification, and web-based services are adding new value to the astronaut-acquired imagery. A coupled ground software and on-orbit hardware system for the ISS is in development for planned deployment in mid-2017; this system will capture camera pose information for each astronaut photograph to allow automated, full georegistration of the data. The ground system component of the system is currently in use to fully georeference imagery collected in response to International Disaster Charter activations, and the auto-registration procedures are being applied to the extensive historical database of imagery to add value for research and educational purposes. In parallel, machine learning techniques are being applied to automate feature identification and classification throughout the dataset, in order to build descriptive metadata that will improve search capabilities. It is expected that these value additions will increase interest and use of the dataset by the global community.

Stefanov, William L.↗

NASA NTRS1974

Space station 'Skylab' - The harvest begins

Initial difficulties connected with the damage suffered by the space station during the launching operation and approaches for overcoming these difficulties are discussed along with the results obtained by the astronauts in their investigations. Attention is given to biomedical results, new solar discoveries, observations of the earth, materials research, and the new products obtained as a result of space processing.

Von Puttkamer, J.↗

NASA NTRS1977

The Shuttle era - A challenge to the earth scientist

Satellite observations of large-scale earth features and phenomena, with either instruments or astronauts, are discussed on the basis of earlier experience (mainly Skylab). Off-nadir views and photographs by astronauts have provided valuable supplements to instrument nadir views, providing cross-checks through remote sensing at different angles, different altitudes, and in different seasons. New information on plate tectonics, global cooling/drying trends, global oceanographic data (changing positions of major ocean current patterns, evolution of warm and cold eddies and their relation to sea temperatures and concentrations of marine fauna, location of internal sea waves, interactions between ocean currents and atmosphere, plankton blooms), storm development, snow cover patterns, lake and sea ice growth, sand-dune patterns, desert storms blown out to sea, effects of grazing and swidden agriculture, and other earth features and phenomena are surveyed.

Muehlberger, W. R.↗

NASA NTRS1993

A unique exercise facility for simulating orbital extravehicular activity

A unique exercise facility has been developed and used to simulate orbital extravehicular activity (EVA). The device incorporates an arm ergometer into a mechanism which places the subject in the zero-g neutral body posture. The intent of this configuration is to elicit muscular, cardiovascular, respiratory, and thermoregulatory responses similar to those observed during orbital EVA. Experiments done with this facility will help characterize the astronaut's dynamic heat balance during EVA and will eventually lead to the development of an automated thermal control system which would more effectively maintain thermal comfort.

Williamson, Rebecca C.↗

NASA NTRSDate not supplied

Exploring the Moon: Training Astronauts for Artemis Missions

For the first time in over 50 years, NASA scientists are training astronauts assigned to lunar missions. The successful Artemis 1 test flight in 2022 set the stage for future human missions to the Moon. The Artemis II mission will send astronauts to fly by the Moon, providing the first opportunity since Apollo for humans to directly observe and document the lunar surface from a few thousand kilometers, including the lunar far side. Artemis III will be the first human mission to land and explore the Moon’s surface near the lunar South Pole. To prepare for Artemis exploration, geology training for the Artemis II crew and detailed training plans for Artemis III and beyond are in full swing. NASA scientists have been working for several years with the Flight Operations Directorate (FOD) at the Johnson Space Center on a progressive geology training program that starts with incoming astronaut classes, offers opportunities to maintain the geology proficiency between flight assignments, and trains the broader engineering-operations-management community in geology and field operations. In the spring of 2023, our team developed an introductory week-long class called Lunar Fundamentals and delivered this content to the Artemis II crew, as well as key NASA Flight Control Team members. The Lunar Fundamentals curriculum combines basic geographic and geologic information about the Moon; includes detailed content on major geologic processes, the lunar environment, lunar volatiles, and sample science; provides historical context of our growing knowledge about the Moon; and introduces new lunar data sets and tools for exploring the lunar surface. With the Lunar Fundamentals foundation, we continue development of the advanced planetary science classroom content for the Artemis III crew, together with field training science objectives and plans. Partnering with our FOD colleagues, we are building an integrated training plan for lunar science, exploration field methods, and operational skills to ensure that the Artemis astronauts exploring the Moon will have the necessary foundation in geology and lunar science to achieve mission success.

Astronauts training↗

NASA NTRSDate not supplied

Surveillance for Jugular Venous Thrombosis in Long-Duration Space Flight: Findings From Twenty-Eight U.S. Astronauts

BACKGROUND: Given the high incidence of internal jugular vein (IJV) flow anomalies aboard the International Space Station and a case of thrombosis, the National Aeronautics and Space Administration (NASA) instituted an occupational surveillance program to evaluate astronauts for venous thromboembolism (VTE). Current findings of the program are presented. METHODS: NASA astronauts undergo pre- and in-flight VTE surveillance examinations using a standardized vascular ultrasound protocol, which includes evaluation for bilateral IJV compressibility, filling, flow, and spontaneous echo contrast (SEC). RESULTS: Twenty-eight NASA astronauts had terrestrial baseline examinations and at least one in-flight imaging session. The reduction of in-flight peak IJV flow speeds was significant and more pronounced on the left. Comparing the first in-flight measurement to the terrestrial baseline, peak flow speeds were reduced from 90.1±41.9 cm/s (average ±SD) to 62.1±31.6 cm/s on the right and from 76.9±41.8 cm/s to 26.8±18.2 cm/s on the left. Seven astronauts showed stagnant or retrograde flow in the left IJV. Fourteen developed appreciable SEC in the left IJV (7 greater than mild); none developed significant right-sided SEC. All IJVs were fully compressible and free from thrombi. DISCUSSION: Bilateral IJV flow speed reduction is observed in microgravity, possibly due to the multitude of available flow redistribution paths for cranial drainage. In a subset of astronauts, significant flow anomalies develop that may facilitate thrombus formation through changes in blood viscosity and speed, especially if combined with other thrombogenic factors. These findings warrant attention to the interplay between individual vascular configurations and the dynamic properties of blood as a non-Newtonian fluid in the reduced-shear flow environment of microgravity.

Ashot Sargsyan↗

NASA NTRS1985

Research opportunities in loss of red blood cell mass in space flight

Decreases of red blood cell mass and plasma volume have been observed consistently following manned space flights. Losses of red cell mass by United States astronauts have averaged 10 to 15% (range: 2 to 21%). Based on postflight estimates of total hemoglobin, Soviet cosmonauts engaged in space missions lasting from 1 to 7 months have exhibited somewhat greater losses. Restoration of red cell mass requires from 4 to 6 weeks following return to Earth, regardless of the duration of space flight.

Talbot, J. M.↗

NASA NTRS2012

Solar Eruptive Events

It s long been known that the Sun plays host to the most energetic explosions in the solar system. But key insights into the forms that energy takes have only recently become available. Solar flares have been phenomena of both academic and practical interest since their discovery in 1859. From the academic point of view, they are the nearest events for studying the explosive release of energy in astrophysical magnetized plasmas. From the practical point of view, they disrupt communication channels on Earth, from telegraph communications in 1859 to radio and television signals today. Flares also wreak havoc on the electrical power grid, satellite operations, and GPS signals, and energetic charged particles and radiation are dangerous to passengers on high-altitude polar flights and to astronauts. Flares are not the only explosive phenomena on the Sun. More difficult to observe but equally energetic are the large coronal mass ejections (CMEs), the ejection of up to ten billion tons of magnetized plasma into the solar wind at speeds that can exceed 1000 km/s. CMEs are primarily observed from the side, with coronagraphs that block out the bright disk of the Sun and lower solar atmosphere so that light scattered from the ejected mass can be seen. Major geomagnetic storms are now known to arise from the interaction of CMEs with Earth's magnetosphere. Solar flares are observed without CMEs, and CMEs are observed without flares. The two phenomena often occur together, however, and almost always do in the case of large flares and fast CMEs. The term solar eruptive event refers to the combination of a flare and a CME. Solar eruptive events generate a lot of heat: They can heat plasma to temperatures as high at 50 million Kelvin, producing radiation across the electromagnetic spectrum. But that s not all. A fascinating aspect of solar eruptive events is the acceleration of electrons and ions to suprathermal often relativistic energies. The accelerated particles are primarily observed through their emissions in the higher energy x-ray, gamma-ray, and rf regimes. The radio and x-ray emissions are both from mildly relativistic electrons with energies of tens of keV and above. Gamma-ray line emission comes indirectly from accelerated protons and heavier ions with MeV and higher energies. The difficulty in collecting spatially and spectrally resolved x-ray and gamma-ray data has long been a barrier to learning about the accelerated particles. Considerable progress has been made in the last decade in understanding the relationship between the flare, the CME, energy release, and particle acceleration. But many new questions have also arisen. In this article, I describe those new insights and our evolving understanding of solar eruptive events.

Holman, Gordon D.↗