This paper describes the activities for utilization and control of ELITE S2 on board the International Space Station (ISS). ELITE S2 is a payload of the Italian Space Agency (ASI) for quantitative human movement analysis in weightlessness. Within the frame of a bilateral agreement with NASA, ASI has funded a number of facilities, enabling different scientific experiments on board the ISS. ELITE S2 has been developed by the ASI contractor Kayser Italia, delivered to the Kennedy Space Center in 2006 for pre-flight processing, launched in 2007 by the Space Shuttle Endeavour (STS-118), integrated in the U.S. lab and used during the Increments 16 and 17 through 2008. The ELITE S2 flight segment comprises equipment mounted into an Express Rack and a number of stowed items to be deployed for experiment performance (video cameras and accessories). The ground segment consists in a User Support Operations Center (based at Kayser Italia) enabling real-time payload control and a number of User Home Bases (located at the ASI and PIs premises), for the scientific assessment of the experiment performance. Two scientific protocols on reaching and cognitive processing have been successfully performed in five sessions involving two ISS crewmembers: IMAGINE 2 and MOVE.
Adaptive optics correction into single mode fiber for a low Earth orbiting space to ground optical communication link using the OPALS downlink
An adaptive optics (AO) testbed was integrated to the Optical PAyload for Lasercomm Science (OPALS) ground station telescope at the Optical Communications Telescope Laboratory (OCTL) as part of the free space laser communications experiment with the flight system on board the International Space Station (ISS). Atmospheric turbulence induced aberrations on the optical downlink were adaptively corrected during an overflight of the ISS so that the transmitted laser signal could be efficiently coupled into a single mode fiber continuously. A stable output Strehl ratio of around 0.6 was demonstrated along with the recovery of a 50 Mbps encoded high definition (HD) video transmission from the ISS at the output of the single mode fiber. This proof of concept demonstration validates multi-Gbps optical downlinks from fast slewing low-Earth orbiting (LEO) spacecraft to ground assets in a manner that potentially allows seamless space to ground connectivity for future high data-rates network.
An ongoing challenge in biomedical research is the search for simple, yet robust assays using 3D cell cultures for toxicity screening. This study addresses that challenge with a novel spheroid assay, wherein spheroids, formed by magnetic 3D bioprinting, contract immediately as cells rearrange and compact the spheroid in relation to viability and cytoskeletal organization. Thus, spheroid size can be used as a simple metric for toxicity. The goal of this study was to validate spheroid contraction as a cytotoxic endpoint using 3T3 fibroblasts in response to 5 toxic compounds (all-trans retinoic acid, dexamethasone, doxorubicin, 5′-fluorouracil, forskolin), sodium dodecyl sulfate (+control), and penicillin-G (-control). Real-time imaging was performed with a mobile device to increase throughput and efficiency. All compounds but penicillin-G significantly slowed contraction in a dose-dependent manner (Z’ = 0.88). Cells in 3D were more resistant to toxicity than cells in 2D, whose toxicity was measured by the MTT assay. Fluorescent staining and gene expression profiling of spheroids confirmed these findings. The results of this study validate spheroid contraction within this assay as an easy, biologically relevant endpoint for high-throughput compound screening in representative 3D environments.
Rapid Access:Dream Chaser® Space Traffic Management and Operations to Enable Near-Immediate Payload Access for Responsive Mission and Payload Support
As research institutions all over the world are placing a higher value on space-based science, the need for rapid access to vehicles returning from space carrying experiments grows more important. One of the challenges of enhanced science utilization is rapid access to space vehicles post-flight, which is significantly enabled by effective space traffic management and integration of space operations into a mature commercial aviation system to achieve radically improved orbit to researcher timelines. Sierra Nevada Corporation’s (SNC) Space Systems’ Dream Chaser® reusable spacecraft is designed for multiple applications including cargo and/or crew resupply to the International Space Station and independent long duration science missions. The Dream Chaser is an optionally-piloted, reusable lifting-body spacecraft that lands horizontally on a runway, similar to the Space Shuttle. Unlike the Space Shuttle, the Dream Chaser design supports the unique capability of being able to land at many domestic and international commercial and public-use airports, and offers access to cargo and/or crew almost immediately thereafter. Though this capability presents a unique opportunity for researchers in the field of microgravity science, there are challenges when considering the current landscape of regulation, public risk, and autonomous flight. The potential opportunities associated with landing the Dream Chaser at public-use airports to enable globally convenient and rapid access to crew, cargo, and time critical microgravity experiments post-flight are identified and addressed in this paper.
Effects of cooling temperature on heat pipe evaporator performance using an ideal fluid mixture in microgravity
The effect of cooling temperature on heat pipe performance has generally received little consideration. In this paper, we studied the performance of a Constrained Vapor Bubble (CVB) heat pipe using a liquid mix- ture of 94 vol%-pentane and 6 vol%-isohexane at different cooling temperatures in the microgravity envi- ronment of the International Space Station (ISS). Using a one-dimensional (1-D) heat transfer model developed in our laboratory, the heat transfer coefficient of the evaporator section was calculated and shown to decrease with increasing cooler temperature. Interestingly, the decreasing trend was not the same across the cooler settings studied in the paper. This trend corresponded with the change in the tem- perature profile along the cuvette. When the cooling temperature went from 0 to 20 C, the temperature of the cuvette decreased monotonically from the heater end to the cooler end and the heat transfer coef- ficient decreased slowly from 456 to 401 (W m 2 K 1) (at a rate of 2.75 W m 2 K 2). However, when the cooling temperature increased from 25 to 35 C, a minimum point formed in the temperature profile, and the heat transfer coefficient dramatically decreased from 355 to 236 (W m 2 K 1) (at a rate of 11.9 W m 2 K 2). A similar change in decreasing trend was observed in the pressure gradient and liquid velocity profile. The reduced heat pipe performance at high cooling temperatures was consistent with the reduced evaporation which was indicated by the decreasing internal heat transfer and the increasing liq- uid film thickness along the cuvette as seen in the surveillance images. The result obtained is important for future heat pipe design because we now have a better understanding of the working temperature ranges of these devices.
Pulse transit time measured by photoplethysmography improves the accuracy of heart rate as a surrogate measure of cardiac output, stroke volume and oxygen uptake in response to graded exercise
Heart rate (HR) is a valuable and widespread measure for physical training programs, although its description of conditioning is limited to the cardiac response to exercise. More comprehensive measures of exercise adaptation include cardiac output (Q), stroke volume (SV) and oxygen uptake (VO2), but these physiological parameters can be measured only with cumbersome equipment installed in clinical settings. In this work, we explore the ability of pulse transit time (PTT) to represent a valuable pairing with HR for indirectly estimating Q, SV and VO2 non-invasively. PTT was measured as the time interval between the peak of the electrocardiographic (ECG) R-wave and the onset of the photoplethysmography (PPG) waveform at the periphery (i.e. fingertip) with a portable sensor. Fifteen healthy young subjects underwent a graded incremental cycling protocol after which HR and PTT were correlated with Q, SV and VO2 using linear mixed models. The addition of PTT significantly improved the modeling of Q, SV and VO2 at the individual level ([Formula: see text] for SV, 0.548 for Q, and 0.771 for VO2) compared to predictive models based solely on HR ([Formula: see text] for SV, 0.503 for Q, and 0.745 for VO2). While challenges in sensitivity and artifact rejection exist, combining PTT with HR holds potential for development of novel wearable sensors that provide exercise assessment largely superior to HR monitors.
This paper will explore the opportunities and challenges in developing the commercial market in LEO through the ISS program and all its facets, including operations, mission support activities, utilization, and contracting. The role of NASA-funded research in the vertical translation of basic research in space to practical application in the market or to other government service agencies will also be addressed. Other aspects, including government regulation, investment and tax incentives, and possible roles of various government agencies will also be explored. Of particular importance, the role of private industry, currently in the supply business, in the development of the demand for LEO capabilities and services beyond the federal government will be highlighted. In conclusion, this paper will address the prospects in reaching the goal of commercializing LEO starting from where we are today in human spaceflight and the International Space Station.
Evaluation of rodent spaceflight in the NASA animal enclosure module for an extended operational period (up to 35 days)
The National Aeronautics and Space Administration Animal Enclosure Module (AEM) was developed as a self-contained rodent habitat for shuttle flight missions that provides inhabitants with living space, food, water, ventilation, and lighting, and this study reports whether, after minimal hardware modification, the AEM could support an extended term up to 35 days for Sprague-Dawley rats and C57BL/6 female mice for use on the International Space Station. Success was evaluated based on comparison of AEM housed animals to that of vivarium housed and to normal biological ranges through various measures of animal health and well-being, including animal health evaluations, animal growth and body masses, organ masses, rodent food bar consumption, water consumption, and analysis of blood contents. The results of this study confirmed that the AEMs could support 12 adult female C57BL/6 mice for up to 35 days with self-contained RFB and water, and the AEMs could also support 5 adult male Sprague-Dawley rats for 35 days with external replenishment of diet and water. This study has demonstrated the capability and flexibility of the AEM to operate for up to 35 days with minor hardware modification. Therefore, with modifications, it is possible to utilize this hardware on the International Space Station or other operational platforms to extend the space life science research use;of mice and rats.
Here we demonstrate a magnetic 3D bioprinting method for rapidly and reproducibly printing three-dimensional (3D) spheroids in high- throughput formats. We show the utility of these spheroids for cell viability testing using the CellTiter-Glo® and RealTime-GloTM Cell Viability Assays.
Experimental elaboration of liquid droplet cooler-radiator models under microgravity and deep vacuum conditions
The basic results of space tests of liquid droplet cooler radiator models as the main elements of frameless systems for low grade heat rejection are considered. The studies carried out have been analyzed and intermediate elaboration’s results are summarized, which concern (1) the development of generators of drop let propellant flows, (2) revealing an operational behavior of fluid collectors of various types and analysis of unsolved problems associated with droplet collection upon the open trajectory’s section passage, and (3) pro vision of the coolant circulation contour’s closing. The necessity is substantiated for the activization of works directed to carrying out space experiments with improved radiator models and new promising propellants in order to provide a possibility of creating new space power plants characterized by megawatt power levels.