Publications Resulting from ISS National Lab Sponsored Projects

Below, explore peer-reviewed journal articles related to ISS National Lab investigations. For a more extensive list of spaceflight-related publications (not limited to ISS National Lab sponsorship), see the International Space Station Research Results Citations on the NASA website.

Butterflies and Spiders in Space: Space Life Science Investigations for the Classroom

Moreno NP, Vogt GL, Denk JP, Countryman S, Stodieck LS, Thomson WA. Butterflies and spiders in space: Space life science investigations for the classroom. Gravitational and Space Biology. 2012; 26(1):77-87.

Two experiments were conducted aboard the International Space Station (ISS) in 2008 and 2009 that engaged elementary and middle school teachers and students worldwide in authentic science investigations designed to increase student knowledge of, and interest in, biology and space life science studies and biomedical careers. In the first project, a pilot called Butterflies and Spiders in Space, 1,876 middle school students tested a protocol for comparing, at near-real time, the behaviors of orb-weaver spiders and painted lady butterflies living in microgravity (aboard ISS) to those of comparable subjects in students' classrooms. Teachers reported that, as a result of project activities, 33% of their students designed additional experiments and 80% of students expressed interest in science careers. The second program, Butterflies in Space, enabled students to observe and investigate the life cycle and behaviors of painted lady butterflies living on ISS, and compare them to butterflies being studied in their own classes. Combining this near real-time experiment with hands-on explorations and webbased instructional strategies, Butterflies in Space reached more than 3,000 teachers, representing an estimated 180,000 students (grades 3-6) or more worldwide. It also received international coverage from a variety of media. Investigators at BioServe Space Technologies of the University of Colorado designed and built the chambers in which the spiders and butterflies were housed on ISS, and led technical and logistical operations for both programs. Baylor College of Medicine (BCM) educators and scientists developed the education framework and managed the web-based distribution of project data and teaching resources.

A Technique for Removing Second-order Light Effects from Hyperspectral Imaging Data

Li R, Lucke RL, Korwan DR, Gao BG. A technique for removing second-order light effects from hyperspectral imaging data. IEEE Transactions on Geoscience and Remote Sensing. 2012;50(3):824-830.

The Hyperspectral Imager for the Coastal Ocean (HICO) instrument currently on board the International Space Station is a new sensor designed specifically for the studies of turbid coastal waters and large inland lakes and rivers. It covers the wavelength range between 0.4 and 0.9 μm with a spectral resolution of 5.7 nm and a spatial resolution of approximately 90 m. The HICO sensor is not equipped with a second-order blocking filter in front of the focal plane array. As a result, the second-order light from the shorter visible spectral region falls onto the detectors covering the near-IR spectral region above 0.8 μm. In order to have accurate radiometric calibration of the near-IR channels, the second-order light contribution needs to be removed. The water-leaving radiances of these near-IR channels over clear ocean waters are close to zero because of strong liquid water absorption above 0.8 μm. Through analysis of HICO imaging data containing features of shallow underwater objects, such as coral reefs, we have developed an empirical technique to correct for the second-order light effects in near-IR channels. HICO data acquired over Midway Island in the Pacific Ocean and the Bahamas Banks in the Atlantic Ocean are used to demonstrate the effectiveness of the new technique.

Remote Automated Multigenerational Growth and Observation of an Animal in Low Earth Orbit

Oczypok EA, Etheridge T, Freeman J, Stodieck LS, Johnsen RC, Baillie D, Szewczyk NJ. Remote automated multigenerational growth and observation of an animal in low Earth orbit. Journal of the Royal Society Interface. 2012; 9(68):596-599.

The ultimate survival of humanity is dependent upon colonization of other planetary bodies. Key challenges to such habitation are (patho)physiologic changes induced by known, and unknown, factors associated with long-duration and distance space exploration. However, we currently lack biological models for detecting and studying these changes. Here, we use a remote automated culture system to successfully grow an animal in low Earth orbit for six months. Our observations, over 12 generations, demonstrate that the multi-cellular soil worm Caenorhabditis elegans develops from egg to adulthood and produces progeny with identical timings in space as on the Earth. Additionally, these animals display normal rates of movement when fully fed, comparable declines in movement when starved, and appropriate growth arrest upon starvation and recovery upon re-feeding. These observations establish C. elegans as a biological model that can be used to detect changes in animal growth, development, reproduction and behaviour in response to environmental conditions during long-duration spaceflight. This experimental system is ready to be incorporated on future, unmanned interplanetary missions and could be used to study cost-effectively the effects of such missions on these biological processes and the efficacy of new life support systems and radiation shielding technologies.

Estimation of Chlorophyll-a Concentration in Productive Turbid Waters using a Hyperspectral Imager for the Coastal Ocean—The Azov Sea Case Study

Gitelson AA, Gao BG, Li R, Berdnikov S, Saprygin V. Estimation of chlorophyll-a concentration in productive turbid waters using a Hyperspectral Imager for the Coastal Ocean—the Azov Sea case study. Environmental Research Letters. 2011;6(2):024023

We present here the results of chlorophyll-a (chl-a) concentration estimation using the red and near infrared (NIR) spectral bands of a Hyperspectral Imager for the Coastal Ocean (HICO) in productive turbid waters of the Azov Sea, Russia. During the data collection campaign in the summer of 2010 in Taganrog Bay and the Azov Sea, water samples were collected and concentrations of chl-a were measured analytically. The NIR–red models were tuned to optimize the spectral band selections and chl-a concentrations were retrieved from HICO data. The NIR–red three-band model with HICO-retrieved reflectances at wavelengths 684, 700, and 720 nm explained more than 85% of chl-a concentration variation in the range from 19.67 to 93.14  mg m − 3 and was able to estimate chl-a with root mean square error below 10  mg m − 3. The results indicate the high potential of HICO data to estimate chl-a concentration in turbid productive (Case II) waters in real-time, which will be of immense value to scientists, natural resource managers, and decision makers involved in managing the inland and coastal aquatic ecosystems.

A New View of Coastal Oceans from the Space Station

Corson MR, Davis CO.  A new view of coastal oceans from the space station. Eos, Transactions American Geophysical Union. 2011;92(19):161-162.

Understanding and quantifying the natural processes that occur along coasts are critical components of managing environmental resources and planning and executing coastal operations, from humanitarian relief to military actions. However, the coastal ocean is complicated, with dissolved and suspended matter that hinders water transparency, phytoplankton blooms that can be toxic, and bathymetry and bottom types that vary over spatial scales of tens of meters, all of which affect processes in an area that spans millions of square kilometers. A hyperspectral imager collects the spectrum of the light received from each pixel in an image. For environmental characterization the wavelength range typically spans the visible and shortwave infrared wavelengths, and the spectrum is collected in contiguous spectral intervals 1–10 nanometers wide. This spectral information is exploited to provide significantly more information about vegetation, minerals, and other components in the scene than can be retrieved from panchromatic or even multispectral imagery, which rely primarily on the shape of the object for detection [Goetz et al., 1985]. Such technology can also work over shallow seas. Over the past 2 decades, experiments with hyperspectral imagers on airborne platforms have demonstrated the ability to characterize the coastal environment [Davis et al., 2002, Davis et al. 2006] and produce maps of coastal bathymetry, in‐water constituents, and bottom type.

The Effects of Space Flight and Microgravity on the Growth and Differentiation of PICM-19 Pig Liver Stem Cells

Talbot NC, Caperna TJ, Blomberg L, Graninger PG, Stodieck LS.  The effects of space flight and microgravity on the growth and differentiation of PICM-19 pig liver stem cells. In Vitro Cellular and Developmental Biology - Animal. 2010;46(6):502-515.

The PICM-19 pig liver stem cell line was cultured in space for nearly 16 d on the STS-126 mission to assess the effects of spaceflight on the liver's parenchymal cells—PICM-19 cells to differentiate into either monolayers of fetal hepatocytes or 3-dimensional bile ductules (cholangiocytes). Semi-quantitative data included light microscopic assessments of final cell density, cell morphology, and response to glucagon stimulation and electron microscopic assessment of the cells' ultrastructural features and cell-to-cell connections and physical relationships. Quantitative assessments included assays of hepatocyte detoxification functions, i.e., inducible P450 activities and urea production and quantitation of the mRNA levels of several liver-related genes. Three post-passage age groups were included: 4-d-, 10-d-, and 14-d-old cultures. In comparing flight vs. ground-control cultures 17 h after the space shuttle's return to earth, no differences were found between the cultures with the exception being that some genes were differentially expressed. By light microscopy both young and older cultures, flight and ground, had grown and differentiated normally in the Opticell culture vessels. The PICM-19 cells had grown to approximately 75% confluency, had few signs of apoptosis or necrosis, and had either differentiated into monolayer patches of hepatocytes with biliary canaliculi visible between the cells or into 3-dimensional bile ductules with well-defined lumens. Ultrastructural features between flight and ground were similar with the PICM-19 cells displaying numerous mitochondria, Golgi apparatus, smooth and rough endoplasmic reticulum, vesicular bodies, and occasional lipid vacuoles. Cell-to-cell arrangements were typical in both flight and ground-control samples; biliary canaliculi were well-formed between the PICM-19 cells, and the cells were sandwiched between the STO feeder cells. PICM-19 cells displayed inducible P450 activities. They produced urea in a glutamine-free medium and produced more urea in response to ammonia. The experiment's aim to gather preliminary data on the PICM-19 cell line's suitability as an in vitro model for assessments of liver function in microgravity was demonstrated, and differences between flight and ground-control cultures were minor.

SPHERES Flight Operations Testing and Execution

 Mohan S, Saenz-Otero A, Nolet S, Miller DW, Sell S. SPHERES flight operations testing and execution. Acta Astronautica. 2009;65(7-8):1121-1132.

Synchronized Position Hold Engage Reorient Experimental Satellites (SPHERES) is a formation flight testing facility consisting of three satellites operating inside the International Space Station (ISS). The goal is to use the long term microgravity environment of the ISS to mature formation flight and docking algorithms. The operations processes of SPHERES have also matured over the course of the first seven test sessions. This paper describes the evolution of the SPHERES program operations processes from conception to implementation to refinement through flight experience. Modifications to the operations processes were based on experience and feedback from Marshall Space Flight Center Payload Operations Center, USAF Space Test Program office at Johnson Space Center, and the crew of Expedition 13 (first to operate SPHERES on station). Important lessons learned were on aspects such as test session frequency, determination of session success, and contingency operations. This paper describes the tests sessions; then it details the lessons learned, the change in processes, and the impact on the outcome of later test sessions. SPHERES had very successful initial test sessions which allowed for modification and tailoring of the operations processes to streamline the code delivery and to tailor responses based on flight experiences.

Development of a Thin Film Solar Cell Interconnect for the PowerSphere Concept

Simburger E, Matsumoto JH, Giants TW, Garcia III A, Liu S, Rawal SP, Perry AR, Marshall CH, Lin JK, Scarborough SE, Curtis HB, Kerslake TW, Peterson TT.  Development of a thin film solar cell interconnect for the PowerSphere concept. Materials Science and Engineering B: Advanced Functional Solid-State Materials. 2005;116(3):321-325.

Progressive development of microsatellite technologies has resulted in increased demand for lightweight electrical power subsystems including solar arrays. The use of thin film photovoltaics has been recognized as a key solution to meet the power needs. The lightweight cells can generate sufficient power and still meet critical mass requirements. Commercially available solar cells produced on lightweight substrates are being studied as an option to fulfill the power needs. The commercially available solar cells are relatively inexpensive and have a high payoff potential. Commercially available thin film solar cells are primarily being produced for terrestrial applications. The need to convert the solar cell from a terrestrial to a space compatible application is the primary challenge. Solar cell contacts, grids and interconnects need to be designed to be atomic oxygen resistant and withstand rapid thermal cycling environments. A mechanically robust solar cell interconnect is also required in order to withstand handling during fabrication and survive during launch. The need to produce the solar cell interconnects has been identified as a primary goal of the PowerSphere program and is the topic of this paper. Details of the trade study leading to the final design involving the solar cell wrap around contact, flex blanket, welding process, and frame will be presented at the conference.

Downregulation of LGR5 Expression Inhibits Cardiomyocyte Differentiation in Potentiates Endothelial Differentiation from Human Pluripotent Stem Cells

Jha R, Singh M, Wu Q, Gentillon C, Preininger MK, Xu C. Downregulation of LGR5 expression inhibits cardiomyocyte differentiation in potentiates endothelial differentiation from human pluripotent stem cells. Stem Cell Reports. 2017;9(2):513-527.

Understanding molecules involved in differentiation of human pluripotent stem cells (hPSCs) into cardiomyocytes and endothelial cells is important in advancing hPSCs for cell therapy and drug testing. Here, we report that LGR5, a leucine-rich repeat-containing G-protein-coupled receptor, plays a critical role in hPSC differentiation into cardiomyocytes and endothelial cells. LGR5 expression was transiently upregulated during the early stage of cardiomyocyte differentiation, and knockdown of LGR5 resulted in reduced expression of cardiomyocyte-associated markers and poor cardiac differentiation. In contrast, knockdown of LGR5 promoted differentiation of endothelial-like cells with increased expression of endothelial cell markers and appropriate functional characteristics, including the ability to form tube-like structures and to take up acetylated low-density lipoproteins. Furthermore, knockdown of LGR5 significantly reduced the proliferation of differentiated cells and increased the nuclear translocation of ?-catenin and expression of Wnt signaling-related genes. Therefore, regulation of LGR5 may facilitate efficient generation of cardiomyocytes or endothelial cells from hPSCs.

Microgravity Validation of a Novel System for RNA Isolation and Multiplex Quantitative Real Time PCR Analysis of Gene Expression on the International Space Station

Parra MP, Jung J, Boone TD, Tran L, Blaber EA, Brown M, Chin M, Chinn T, Cohen JN, Doebler R, Hoang D, Hyde E, Lera MP, Luzod LT, Mallinson M, Marcu O, Mohamedaly Y, Ricco AJ, Rubins K, Sgarlato GD, Talavera RO, Tong P, Uribe E, Williams JN, Wu D, Yousuf R, Richey CS, Schonfeld J, Almeida EA. Microgravity validation of a novel system for RNA isolation and multiplex quantitative real time PCR analysis of gene expression on the International Space Station. PLoS ONE. 2017;12(9):e0183480.

The International Space Station (ISS) National Laboratory is dedicated to studying the effects of space on life and physical systems, and to developing new science and technologies for space exploration. A key aspect of achieving these goals is to operate the ISS National Lab more like an Earth-based laboratory, conducting complex end-to-end experimentation, not limited to simple microgravity exposure. Towards that end NASA developed a novel suite of molecular biology laboratory tools, reagents, and methods, named WetLab-2, uniquely designed to operate in microgravity, and to process biological samples for real-time gene expression analysis on-orbit. This includes a novel fluidic RNA Sample Preparation Module and fluid transfer devices, all-in-one lyophilized PCR assays, centrifuge, and a real-time PCR thermal cycler. Here we describe the results from the WetLab-2 validation experiments conducted in microgravity during ISS increment 47/SPX-8. Specifically, quantitative PCR was performed on a concentration series of DNA calibration standards, and Reverse Transcriptase-quantitative PCR was conducted on RNA extracted and purified on-orbit from frozen Escherichia coli and mouse liver tissue. Cycle threshold (Ct) values and PCR efficiencies obtained on-orbit from DNA standards were similar to Earth (1 g) controls. Also, on-orbit multiplex analysis of gene expression from bacterial cells and mammalian tissue RNA samples was successfully conducted in about 3 h, with data transmitted within 2 h of experiment completion. Thermal cycling in microgravity resulted in the trapping of gas bubbles inside septa cap assay tubes, causing small but measurable increases in Ct curve noise and variability. Bubble formation was successfully suppressed in a rapid follow-up on-orbit experiment using standard caps to pressurize PCR tubes and reduce gas release during heating cycles. The WetLab-2 facility now provides a novel operational on-orbit research capability for molecular biology and demonstrates the feasibility of more complex wet bench experiments in the ISS National Lab environment.

Phenotypic Changes Exhibited by E. coli Cultured in Space

Zea L, Larsen M, Estante F, Qvortrup K, Moeller R, Dias de Oliveira S, Stodieck L, Klaus D. Phenotypic changes exhibited by E. coli cultured in space. Front Microbiol. 2017;8:1598.

Bacteria will accompany humans in our exploration of space, making it of importance to study their adaptation to the microgravity environment. To investigate potential phenotypic changes for bacteria grown in space, Escherichia coli was cultured onboard the International Space Station with matched controls on Earth. Samples were challenged with different concentrations of gentamicin sulfate to study the role of drug concentration on the dependent variables in the space environment. Analyses included assessments of final cell count, cell size, cell envelope thickness, cell ultrastructure, and culture morphology. A 13-fold increase in final cell count was observed in space with respect to the ground controls and the space flight cells were able to grow in the presence of normally inhibitory levels of gentamicin sulfate. Contrast light microscopy and focused ion beam/scanning electron microscopy showed that, on average, cells in space were 37% of the volume of their matched controls, which may alter the rate of molecule–cell interactions in a diffusion-limited mass transport regime as is expected to occur in microgravity. TEM imagery showed an increase in cell envelope thickness of between 25 and 43% in space with respect to the Earth control group. Outer membrane vesicles were observed on the spaceflight samples, but not on the Earth cultures. While E. coli suspension cultures on Earth were homogenously distributed throughout the liquid medium, in space they tended to form a cluster, leaving the surrounding medium visibly clear of cells. This cell aggregation behavior may be associated with enhanced biofilm formation observed in other spaceflight experiments.

ISS as a Platform for Optical Remote Sensing of Ecosystem Carbon Fluxes: A Case Study Using HICO

Huemmrich KF, Campbell PKE, Gao BC, Flanagan LB, Goulden M. ISS as a platform for optical remote sensing of ecosystem carbon fluxes: A case study using HICO. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. 2017;10(10):4360-4375.

Data from the hyperspectral imager for coastal ocean (HICO), mounted on the International Space Station (ISS), were used to develop and test algorithms for remotely retrieving ecosystem productivity. Twenty-six HICO images were used from four study sites representing different vegetation types: grasslands, shrubland, and forest. Gross ecosystem production (GEP) data from eddy covariance were matched with HICO-derived spectra. Multiple algorithms were successful relating spectral reflectance with GEP, including: spectral vegetation indices (SVI), SVI in a light-use efficiency model framework, spectral shape characteristics through spectral derivatives and absorption feature analysis, and statistical models leading to multiband hyperspectral indices from stepwise regressions and partial least squares regression. Suc- cessful algorithms were able to achieve r2 better than 0.7 for both GEP at the overpass time and daily GEP. These algorithms were successful using a diverse set of observations combining data from multiple years, multiple times during growing season, different times of day, with different view angles, and different vegetation types. The demonstrated robustness of the algorithms presented in this study over these conditions provides some confidence in mapping spatial patterns of GEP, describing variability within fields, as well as the regional patterns. The ISS orbit provides periods with multiple observations collected at different times of the day within a period of a few days. Diurnal GEP patterns were estimated comparing the half-hourly average GEP from the flux tower against HICO estimates of GEP (r2 = 0.87) if morning, midday, and afternoon observations were available.

Genetic Dissection of the Arabidopsis Apaceflight Transcriptome: Are Some Responses Dispensable for the Physiological Adaptation of Plants to Spaceflight?

Paul A-L, Sng NJ, Zupanska AK, Krishnamurthy A, Schultz ER, Ferl RJ. Genetic dissection of the Arabidopsis spaceflight transcriptome: Are some responses dispensable for the physiological adaptation of plants to spaceflight? PLoS ONE. 2017;12(6):e0180186.

Experimentation on the International Space Station has reached the stage where repeated and nuanced transcriptome studies are beginning to illuminate the structural and metabolic differences between plants grown in space compared to plants on the Earth. Genes that are important in establishing the spaceflight responses are being identified, their roles in spaceflight physiological adaptation are increasingly understood, and the fact that different genotypes adapt differently is recognized. However, the basic question of whether these spaceflight responses are actually required for survival has yet to be posed, and the fundamental notion that spaceflight responses may be non-adaptive has yet to be explored. Therefore the experiments presented here were designed to ask if portions of the plant spaceflight response can be genetically removed without causing loss of spaceflight survival and without causing increased stress responses. The CARA experiment compared the spaceflight transcriptome responses in the root tips of two Arabidopsis ecotypes, Col-0 and WS, as well as that of a PhyD mutant of Col-0. When grown with the ambient light of the ISS, phyD plants displayed a significantly reduced spaceflight transcriptome response compared to Col-0, suggesting that altering the activity of a single gene can actually improve spaceflight adaptation by reducing the transcriptome cost of physiological adaptation. The WS genotype showed an even simpler spaceflight transcriptome response in the ambient light of the ISS, more broadly indicating that the plant genotype can be manipulated to reduce the cost of spaceflight adaptation, as measured by transcriptional response. These differential genotypic responses suggest that genetic manipulation could further reduce, or perhaps eliminate the metabolic cost of spaceflight adaptation. When plants were germinated and then left in the dark on the ISS, the WS genotype actually mounted a larger transcriptome response than Col-0, suggesting that the in-space light environment affects physiological adaptation, which implies that manipulating the local habitat can also substantially impact the metabolic cost of spaceflight adaptation.