Adaptive changes during space flight in how the brain integrates vestibular cues with visual, proprioceptive, and somatosensory information can lead to impaired movement coordination, vertigo, spatial disorientation, and perceptual illusions following transitions between gravity levels. This joint ESA-NASA pre- and post-flight experiment is designed to examine both the physiological basis and operational implications for disorientation and tilt-translation disturbances in astronauts following short-duration space flights.

The first specific aim is to examine the effects of stimulus frequency on adaptive changes in eye movements and motion perception during independent tilt and translation motion profiles. Roll motion is provided by a variable radius centrifuge. Pitch motion is provided by NASA's Tilt-Translation Sled in which the resultant gravitoinertial vector remains aligned with the body longitudinal axis during tilt motion (referred to as the Z-axis gravitoinertial or ZAG paradigm). We hypothesize that the adaptation of otolith-mediated responses to these stimuli will have specific frequency characteristics, being greatest in the mid-frequency range where there is a crossover of tilt and translation.

The second specific aim is to employ a closed-loop nulling task in which subjects are tasked to use a joystick to null-out tilt motion disturbances on these two devices. The stimuli consist of random steps or sum-of-sinusoids stimuli, including the ZAG profiles on the Tilt-Translation Sled. We hypothesize that the ability to control tilt orientation will be compromised following space flight, with increased control errors corresponding to changes in self-motion perception.

The third specific aim is to evaluate how sensory substitution aids can be used to improve manual control performance. During the closed-loop nulling task on both devices, small tactors placed around the torso vibrate according to the actual body tilt angle relative to gravity. We hypothesize that performance on the closed-loop tilt control task will be improved with this tactile display feedback of tilt orientation.

The current plans include testing on eight crewmembers following Space Shuttle missions or short stay onboard the International Space Station. Measurements are obtained pre-flight at L-120 (±30), L-90 (±30), and L-30, (±10) days and post-flight at R+0, R+1, R+2 or 3, R+4 or 5, and R+8 days. Pre- and post-flight testing (from R+1 on) is performed in the Neuroscience Laboratory at the NASA Johnson Space Center on both the Tilt-Translation Device and a variable radius centrifuge. A second variable radius centrifuge, provided by DLR for another joint ESA-NASA project, has been installed at the Baseline Data Collection Facility at Kennedy Space Center to collect data immediately after landing. ZAG was initiated with STS-122/1E and the first post-flight testing will take place after STS-123/1JA landing.

Acknowledgements – This work is supported by ESA, CNES, and NASA Non-Exercise Physiology Countermeasures Project. We thank the Life Sciences Program group at the NASA Kennedy Space Center for their support with the installation of the equipment in the BDCF and post-flight testing.

The project Cardiovascular and cerebrovascular Control on return from the International Space Station (CCISS) is designed to study an integrated view of blood flow control to establish the weak links that make astronauts more susceptible to fainting on return from space. To date, we have collected complete data on two astronauts. We are examining with non-invasive ultrasound the factors that regulate the ability of the veins to return blood to the heart, the contractile properties of the heart and the ability of the arteries to constrict to maintain blood pressure, as well as cerebrovascular autoregulation and CO2 responsiveness. In addition, we use 24-hour monitoring of the heart rate and physical activity patterns and the spontaneous baroreflex with in-flight measurements early and late flight. Preliminary data analysis will focus on the pre-flight responses of the astronauts and their backups examining the relationship between central venous pressure, cardiac output and total peripheral resistance during LBNP. Data will be presented for heart rate and physical activity monitoring in-flight. Post-flight, we have obtained data from astronauts within 2.5-hours of landing and prior to their return to an upright posture. We have observed that post-flight cerebral blood flow velocity increased by 36.0% with a 9.0% decrease cerebrovascular resistance index. As well, the post-flight response to CO2 was partially blunted with a smaller decrease in resistance (6.8%) and smaller increase in flow velocity (22.8%). 24-hour heart rate responses were well maintained during space flight and revealed the anticipated increases during periods of physical activity and reductions with rest and sleep. Funded by the Canadian Space Agency.

During everyday life, baroreflex-mediated cardiovascular adjustments are essential in maintaining blood pressure control on a beat-to-beat basis. In astronauts in space, gravitational pressure gradients do not arise in the circulation so that baroreflex function remains chronically unchallenged. This is likely to affect the neural control of heart rate and blood pressure; however the way in which this occurs is incompletely understood. We tested the hypothesis that neural cardiovascular control in space will be in between preflight standing and supine control.

We studied nine male cosmonauts who each took part in seven different space missions aboard the ISS (age 40 – 52 yrs, height 1.69 – 1.85 m, weight 67 – 90 kg). Data collection was performed between 30 and 45 days before launch in the standing and supine positions, and after 8 days into spaceflight. Cosmonauts were carefully trained to perform in-flight data collection by themselves. They were instructed to pace their breathing to a fixed rate of 12 breaths per minute (0.2 Hz) for a total duration of 3 minutes. The electrocardiogram and beat-by-beat finger arterial blood pressure were recorded at 1-kHz sample rate. Respiratory rate was evaluated using an abdominal pressure sensor. We used power spectral analysis to calculate respiratory sinus arrhythmia (RSA) as well as the low-frequency (0.04 - 0.15 Hz) powers of spontaneous oscillations in heart rate and systolic blood pressure. Baroreflex sensitivity (BRS) was estimated in the time domain using cross-correlation analysis.

As expected, there was a rise in heart rate upon assuming the standing position before spaceflight (59 ± 6 to 79 ± 11 beats per min; p < 0.001). This was accompanied by an increase in mean arterial blood pressure (84 ± 6 to 93 ± 6 mmHg; p < 0.001). Standing up further induced a marked increase in the low-frequency powers of systolic blood pressure oscillations (8 ± 7 to 17 ± 11 mmHg2; p = 0.018), whereas those in heart rate remained unchanged (445 ± 512 to 621 ± 799 ms2; p = 0.315). Alternatively, there was a reduction in RSA from 546 ± 167 ms2 to 158 ± 298 ms2 and in spontaneous BRS from 14 ± 5 ms/mmHg to 6 ± 2 ms/mmHg upon changing from supine to standing (both p < 0.001). After a week of weightlessness in space, heart rate (61 ± 8 beats per min) and mean blood pressure (83 ± 6 mmHg) returned to the pre-flight supine values. This was also true for the low-frequency powers of systolic blood pressure (7 ± 4 mmHg2) and of heart rate (741 ± 716 ms2), as well as for RSA (465 ± 269 ms2) and spontaneous BRS (14 ± 4 ms/mmHg).

Our data show that both heart rate and blood pressure in space correspond to pre-flight supine values. In-flight cardiovascular control is further characterized by chronically increased vagal-cardiac modulation and suppressed sympathetic vasomotor activity, compared with the upright posture on Earth. We therefore have to reject our hypothesis that cardiovascular control after a week into spaceflight is shifted in between standing and supine control.

Many organ systems adapt in response to the removal of gravity, such as that occurring during spaceflight. Such adaptation occurs over varying time periods depending on the organ system being considered, but the effect is that upon a return to the normal 1G environment, the organ system is ill-adapted to that environment. As a consequence, either countermeasures to the adaptive process in flight, or rehabilitation upon return to 1G is required. The lung shows profound and extremely rapid changes when gravity eliminated, but based on short duration spaceflight studies (1-2 weeks in length) shows an immediate return to the normal preflight state upon return.

To determine whether the lung changed in response to a long period without gravity, we studied numerous aspects of lung function on 10 subjects (1 female) before and after they were exposed to 4-6 months of microgravity (µG, weightlessness) in the normobaric, normoxic environment of the International Space Station. A subset of the measurements were able to be preformed during the period on the ISS. Vital capacity was essentially unchanged, and respiratory muscle strength was well maintained during extended exposure to µG, and was unchanged following return to 1G. With the exception of small (and likely physiologically inconsequential) changes in expiratory reserve volume, one index of peripheral gas mixing in the periphery of the lung , and a possible slight reduction in diffusing capacity of the lung for carbon monoxide in the early postflight period, lung function was unaltered by 4-6 months in µG. These results suggest that unlike many other organ systems in the human body, lung function returns to normal after long term exposure to the removal of gravity. We conclude that that in a normoxic, normobaric environment, lung function is not a concern following long-duration future spaceflight exploration missions.

The study aims to a better understanding on the functioning and motor adaptation of multi-sensory interaction within the Central Nervous System (CNS), both at peripheral and central level. During spaceflight, the negligible gravito-inertial force modifies both sensory information available for estimating the spatial orientation of the body and the biomechanical affordances available for achieving motor tasks. Thus, new motor strategies, similar to those that are manifested on Earth in response to disease, must be developed, by a recalibration of internal models. This work consists of recording and analysing astronauts’ motor behaviour during their prolonged space missions on the International Space Station (ISS). The kinematic data recording is carried out by the Italian payload ELITE-S2, an optoelectronic system for motion analysis, onboard the ISS since August 2007. Its exploitation is a rare opportunity to collect data about the human motor learning in no-gravity staying of several months.

The defined protocol is called MOVE, Movement in Orbital Vehicle Experiments; it schedules 48 trials of whole body pointing, half of trials brushing the target and half exchanging force freely with it. The first astronaut involved in the experimental sessions was Leopold Eyharts (mission STS-122); he performed two in-flight sessions, in order to monitor the time course of in-flight changes.

A preliminary kinematic analysis pointed out the reliability of acquired data; the biomechanical model was applied for 3D data reconstruction, proving a good working of the payload and the protocol definition. A detailed kinematic analysis is being performed, by detecting the body segments and angular coordination; the data elaboration aims at highlighting the control strategies, based on both parameters characterizing typically the on-ground posture behaviour, as the center of body mass, and parameters mainly linked to the focal component of the specific task, as the end-point trajectory. A further analysis to compare the astronaut’s on-ground strategies, detected during the pre-flight and post-flight sessions, will be carried out.

We know that human sensory-motor system is trained to change position in Earth’s ubiquitous gravitation field with little or no cognitive effort, by dynamically stabilizing the center of mass within the effective limits of support. These findings will explain whether, as hypothesized, the microgravity-induced changes, as in-flight time increases, occur at a central level, by defining new feedforward schemes, but without eliminating the terrestrial motor programs. At the present other astronauts are involved in the ELITE-S2 missions onboard the ISS.

An accurate representation of the visual environment is crucial for successful interaction with the objects in that environment. It is clear that humans have mental representations of their spatial environment and that these representations are useful, if not essential, in a wide variety of cognitive tasks such as identification of objects and landmarks, guiding actions and navigation, and in directing spatial awareness and attention. It is well known that gravity and visual factors (such as symmetry and elongation) are critical for the identification of an object's reference frame. Consequently, measuring the changes in the mental representation of an object throughout a space mission is a simple way to assess how the gravitational reference frame is taken into account for spatial orientation.

Based on preliminary data obtained during previous space studies by our group, it was hypothesized that the absence of the gravitational reference system, which determines on Earth the vertical direction, influences the mental representation of the vertical dimension of objects and volumes. An experiment was developed to evaluate the cognitive and perceptual-motor changes in mental representation during long-duration spaceflight. The 3DSPACE experiment is a joint effort between ESA and NASA to develop a simple virtual reality platform to enable astronauts/cosmonauts to complete a series of tests while aboard the International Space Station. These tests will provide insights into the effects of microgravity on: (a) Depth Perception, by presenting 2D geometric illusions and 3D objects that subjects adjust with a finger trackball; (b) Distance Perception, by presenting natural or computer-generated 3D scenes where subjects estimate and report absolute distances or adjust distances; and (c) Handwriting/Drawing, by analyzing trajectories and velocities when subjects write or draw memorized objects with an electronic pen on a digitizing tablet.

The objective of these tasks is to identify problems associated with 3D perception in astronauts with the goal of developing countermeasures to alleviate any associated performance risks. Hardware and software development has been completed, and the first measurements should be performed during Increment 17 in the Spring of 2008. Ground-based studies are simultaneously performed on Earth in normal subjects and patients with otolith-dependent vertigo.

Introduction: Alterations of the immune system have been reported since the Apollo missions. The ongoing IMMUNO study on the ISS seeks to gather information on the regulation of major immune functions during 6 months long-term missions. Here, we report on first preliminary data on selected immunologic functions of cells of innate and adaptive immunity.

Methods: Blood was collected from Cosmonauts before Launch (L-30), on the ISS (R-60, R-7) and at the 1st, 7th & 30th day after Return (R+1, R+7, R+30). Innate Immunity: Expression of adhesion molecules ©2-intergins (CD11b/CD18) and L-selectin (CD62L) on granulocytes (PMN) was measured by fow cytometry. H2O2 production was determined by flow cytometry using dihydrorhodamine (DHR) in resting granulocytes and upon stimulation with Ca++ ionophore A23187 (A23). Adaptive immunity was estimated from plasma levels of T cell cytokines and by ex vivo incubation of whole blood with bacterial or viral recall antigens (in vitro Delayed Type Hypersensitivity DTH, Immumed).

Results and Discussion: After space flight intrinsic activation of PMN was shown by increased expression of ©2-integrins and enhanced shedding of L-selectins and by an increased capacity to spontaneously produce H2O2. Paradoxically, activation of PMN was associated with a severe depression of the ability of cells to adequately respond to Ca++ dependent activation (Tbl.1).

CD11b/CD18; CD62L; H2O2 -Spont.; H2O2 A23
L -30 9,7±0,6; 24,3±1,4 ; 12,3±1,5; 238±89
R +1 18,0±5; 18,0±1,2*: 23,5±7,3; 84,2±52*
R +7 16,3±3,4* ; 19,0±1,1*; 16,6±2,1; 35,6±8,7*
R +30 10,0±3,7; 22,1±3,1; 17,4±4,4; 207,4±6,1
Tbl.1: Adhesion molecules expression and hydrogen peroxide (H2O2) production from granulocytes (PMN) (n=3-4, arbitrary units, Means±SEM, T-test vs. L-30, *p<0.1).

Plasma concentrations of T-cell cytokines (IL-2and INF-¥ã) decreased mid-inflight (R-60) and reached almost preflight levels before planned return to earth (R-7) and remained elevated until the first day again on earth (R+1). Thereafter (R+7, R+30) cytokine concentrations dropped again to lower concentration as observed in-flight at R-60. The changes of T-cell cytokine plasma concentrations were confirmed by the individuals' depressed DTH reactions to bacteria (n=3) and virus antigens (n=4) tested in vitro (data not shown).

IL-2; INF-¥ã
RL -30 9,36±2,2; 63,4±44
R -60 1,44±0,4; 16,7±3,9
R -7 7,98±5,8; 51,2±25
R +1 10,1±6,3; 65,4±33
R +7 3,3±5,8; 26,7±89
R +30 5,6±1,6; 38,8±7,9
Tbl.2. Observations on cytokine concentrations [pg/ml]. Due to the limited number of individuals, only descriptive statistical analyses were performed (Means±SEM,n=2-4).

Conclusions Although a small number of individuals were studied, our preliminary data show that long-term space flight leads to activation of those granulocyte functions that are known to potentially cause oxidative tissue damage. This may result from disturbances in the cells' Ca++homeostasis. Moreover, the almost parallel time course of T-cell cytokine plasma concentration profiles and of DTH responses to viral and bacterial recall antigens likely indicate a state of acquired suppression of the adaptive part of the immune system. Attenuation of T-cell associated immune reactivity became evident after 4 months space flight, recovered transiently with the upcoming end of mission -likely due to acute stress experienced during preparation for landing- but became compromised thereafter again (50WB0523)