Volume 5 (2017): Issue 2 (December 2017)

On Sunday, June 19, 2016, a Space Acceleration Measurement System triaxial sensor head flew on a suborbital flight aboard Blue Origin's New Shepard vehicle to collect precision vibratory accelerometry data. The Space Acceleration Measurement System (SAMS) sensor head was mounted inside of a Blue Origin single payload locker inside of the crew capsule. This paper describes the configuration, capture, and analysis of the SAMS data from this flight along with other, related flight log information provided by Blue Origin. Three overlapping periods during the flight were identified and characterized to provide future users of the platform with insight into options that may prove suitable for their research needs. Average accelerations in the Post-Separation Period were consistent with other low-g research platforms, while the shorter Microgravity Period in the middle of the flight showed ultra-quiet vibratory acceleration environments. Researchers can consider this microgravity quality versus time a tradeoff in their experimental designs.

Increasing efforts to move into space have driven the need for new facilities that are capable of simulating weightlessness and other space gravity conditions on Earth. Simulation of weightlessness/microgravity (approximately 10⁻⁶g) is conducted in different earthbound and flight-based facilities, often with poor availability. Other conditions such as lunar or Martian gravity with their partial Earth gravity/hypogravity cannot be performed at a large scale for scientific research on Earth. For multiple Earth gravity/hypergravity, simulation centrifuges are available, but they do not allow the possibility of abrupt acceleration changes. To support this wide range of conditions, a new technique is being developed to combine all of these requirements into a single drop tower facility. Currently under construction, the Einstein-Elevator of the Hannover Institute of Technology at the Leibniz Universität Hannover is an earthbound tool created for simulating micro-, hypo-, and hypergravity research with a high repetition rate. The facility will be capable of performing 100 experiments per day (8-h work shift), each creating 4 s of microgravity. For the first time, statistics can be applied in experiments under space gravity conditions at favorable costs and short mission times. The Einstein-Elevator offers room for large experiments with a diameter up to 1.7 m and a height up to 2 m as well as weights up to 1,000 kg. To perform larger experiments under different gravitational conditions, it was necessary to develop an innovative drive and guide concept. The Einstein-Elevator will be available for general research under different gravity conditions from 2018 onward.

An E-1 payload, the Microgravity Materials Joining Investigative Chamber (MMaJIC), was designed and built for use aboard the International Space Station to investigate soldering and brazing phenomena in a microgravity environment. MMaJIC is a self-contained unit employing a microcontroller that runs a pre-programed experiment, monitors safety sensors, and supports temperature and video recording. MMaJIC uses individual experiment trays that can be easily modified for a specific investigation. The trays, which include a temperature/video data acquisition card, can be easily changed out and returned to Earth for evaluation. Simple operation of MMaJIC minimizes astronaut time while ensuring maximum sample throughput. It is expected that the results will shed considerable light on soldering and brazing in low-gravity environments, information that is important for NASA in conducting comprehensive repair and/or fabrication operations during long duration space missions.

Thin liquid films on isothermal substrates, where the film is flat and parallel to the substrate, succumb to thermocapillary instabilities and rupture, forming local hot-spots. These long wavelength instabilities are specific to aspect ratios where the liquid film mean thickness is several orders of magnitude less than the substrate characteristic dimension. Absent stabilizing gravitational acceleration, the growth rate of thermocapillary instabilities is further intensified, driving the film to rupture even earlier.

Numerical simulations of zero gravity dynamics of Newtonian liquid films on a solid, horizontal, isothermal substrate were conducted. When the solid, isothermal substrate was replaced with a one-dimensionally porous substrate, was fully saturated with the same fluid as the liquid film, and was deep enough to accommodate all the liquid on it, we observed that destabilizing spatial modes were damped thereby preventing rupture and prolonging the film lifespan. This nonlinear evolution was visualized and quantified using recurrence plots.

It is not fully understood how cells detect external mechanical forces, but mechanosensitive ion channels play important roles in detecting and translating physical forces into biological responses (mechanotransduction). With the “OoClamp” device, we developed a tool to study electrophysiological processes, including the gating properties of ion channels under various gravity conditions. The “OoClamp” device uses an adapted patch clamp technique and is operational during parabolic flight and centrifugation up to 20 g. In the framework of the REXUS/BEXUS program, we have further developed the “OoClamp” device with the goal of conducting electrophysiological experiments aboard a flying sounding rocket. The aim of such an experiment was first to assess whether electrophysiological measurements of Xenopus laevis oocytes can be performed on sounding rocket flights, something that has never been done before. Second, we aimed to examine the gating properties of ion channels under microgravity conditions. The experiment was conducted in March 2016 on the REXUS 20 rocket. The post-flight analysis showed that all recording chambers were empty as the rocket reached the microgravity phase. A closer analysis of the flight data revealed that the oocytes were ripped apart a few seconds after the rocket launch. This first attempt at using sounding rockets as a research platform for electrophysiological recordings was therefore limited. Our modified “OoClamp” hardware was able to perform the necessary tasks for difficult electrophysiological recordings aboard a sounding rocket; however, the physical stresses during launch (acceleration and vibrations) did not support viability of Xenopus oocytes.

Spaceflight studies offer a unique opportunity to examine the impact of gravity on developing motor skills. Previously, we reported that young rats experiencing microgravity in low Earth orbit (LEO) beginning on postnatal day (P)14 showed impaired swimming, walking, and surface righting after returning to 1 g, with immature motor skills persisting until adulthood. Here, we report on post-flight surface righting and swimming of rats experiencing spaceflight from P7 or P8. Litters with dams were flown aboard a space shuttle Space Transportation System (STS) 9-day (NIH-R3, STS-72) or 16-day mission (Neurolab, STS-90). Flight rats from both missions showed significantly fewer mature, age-appropriate righting tactics after landing compared to ground controls. Flight rats also had a steeper body angle while floating in the water before swimming, started swimming sooner, and swam faster. The effects on surface righting persisted for the duration of behavior tests (6 days [9-day mission] or 23 days [16-day mission]), after landing. Differences in pre-swimming behavior resolved by return day (R)2, and differences in swimming speed and posture resolved by R10. These data suggest that exposure to microgravity at a young age prevents the normal development of surface righting and that the normal development of swimming can recover if animals return from LEO by P16 or P24. These findings lend additional support to the existence of a critical period of development for motor function. However, studies are needed with improved housing during spaceflight to ensure that maternal offspring behavior is not disrupted, as was observed during the Neurolab mission.

The aim of this study was to determine the hemodynamic and neuroendocrinological responses to different levels and protocols of artificial gravity, especially in comparison to what is expected during a moderate bout of exercise. Ten male participants were exposed to artificial gravity using two different protocols: the first was a centrifugation protocol that consisted of a constant phase of 2 Gz for 30 minutes, and the second consisted of an intermittent phase of 2 Gz for two minutes, separated by resting periods for three minutes in successive order. Near infrared spectroscopy (oxyhemoglobin and deoxyhemoglobin) at the prefrontal cortex, Musculus biceps brachii, and Musculus gastrocnemius, as well as heart rate and blood pressure were recorded before, during, and after exposure to artificial gravity. In order to determine effects of artificial gravity on neuroendocrinological parameters (brain-derived neurotrophic factor, vascular endothelial growth factor, and insulin-like growth factor 1), blood samples were taken before and after centrifugation. During the application of artificial gravity the concentration of oxyhemoglobin decreased significantly and the concentration of deoxyhemoglobin increased significantly in the prefrontal cortex and the Musculus biceps brachii muscle. Participants exposed to the continuous artificial gravity profile experienced peripheral pooling of blood. No changes were observed for brain-derived neurotrophic factor, vascular endothelial growth factor, or insulin-like growth factor 1. Intermittent application of artificial gravity may represent a better-tolerated presentation for participants as hemodynamic values normalize during resting periods. During both protocols, heart rate and arterial blood pressure remained far below what is experienced during moderate physical activity.

We report on the detection of microorganisms onboard the International Space Station (ISS) using an electronic nose we named the E-Nose. The E-Nose, containing an array of ten different metal oxide gas sensors, was trained on Earth to detect the four most abundant microorganisms that are known to exist onboard the ISS. To assess its performance in space, the E-Nose was brought to the ISS and three measurement campaigns were carried out in three different locations inside the ISS during a 5-month mission. At the end of this mission, all investigated locations were wiped with swabs, and the swabs and odor sensor signal data were sent back to Earth for an in-depth analysis in earthbound laboratories. The in-space measurements were compared with an odor database containing four organisms, but a consensus odor could not be identified. Microbiological results could not provide clues to the smell that was measured. The yeast Rhodotorula mucilaginosa was identified in the literature as the most probable candidate for the unknown odor. Further investigations showed that the smell of Rhodotorula mucilaginosa matches very well with the data obtained inside the ISS. Finally, Rhodotorula mucilaginosa DNA was identified in swabs taken from the sleeping cabin of the astronaut, which confirms the assumption that the yeast Rhodotorula mucilaginosa was actually measured in space by the E-Nose.