The Aouda.X space suit simulator and its applications to astrobiology

We have developed the space suit simulator Aouda.X, which is capable of reproducing the physical and sensory limitations a flight-worthy suit would have on Mars. Based upon a Hard-Upper-Torso design, it has an advanced human-machine interface and a sensory network connected to an On-Board Data Handling system to increase the situational awareness in the field. Although the suit simulator is not pressurized, the physical forces that lead to a reduced working envelope and physical performance are reproduced with a calibrated exoskeleton. This allows us to simulate various pressure regimes from 0.3-1 bar. Aouda.X has been tested in several laboratory and field settings, including sterile sampling at 2800 m altitude inside a glacial ice cave and a cryochamber at -110°C, and subsurface tests in connection with geophysical instrumentation relevant to astrobiology, including ground-penetrating radar, geoacoustics, and drilling. The communication subsystem allows for a direct interaction with remote science teams via telemetry from a mission control center. Aouda.X as such is a versatile experimental platform for studying Mars exploration activities in a high-fidelity Mars analog environment with a focus on astrobiology and operations research that has been optimized to reduce the amount of biological cross contamination. We report on the performance envelope of the Aouda.X system and its operational limitations.     

An extensible on-board data handling software platform for pico satellites

Miniaturization techniques enable the realization of very small satellites with interesting capabilities in space science. The University of Würzburg contributed in the scope of the cubesat program with its own pico satellite UWE-1, which is in orbit since October 2005. Despite reliable and stable operation of the on-board data handling (OBDH) system during the UWE-1 mission, the successor UWE-2 will be equipped with a more sophisticated, modular and extensible OBDH system, which was designed to facilitate the further development of the UWE satellite platform. The OBDH system was designed for high reliability and stability, but with an easier extension capability. The modular structure of the new system thus supports potential transfer to other satellite platforms.     

Ion Temperatures as Observed in a Solar Coronal Hole

From the widths of the extreme ultraviolet (EUV) lines measured by the SUMER instrument on SOHO, it was found previously (Tu et al. 1998) that the average temperature of Ne⁺⁷, at heights (relative to h₀) above the southern solar limb from 17″ to 64″, ranges between 1.3 and 5 × 10⁶ K and of Ne⁺⁶ between 1 and 4 × 10⁶ K. For mass-per-charge numbers greater than 4 the temperatures of the ions increase slightly with increasing mass-per-charge, while the thermal speed reveals no clear trend. We present a new data set with exposure times much longer than the ones in the previous study. The results obtained from line width analysis of Fe XII (1242 Å), Mg X (1249 Å), Mg VIII (772 Å) Ne VIII (770 Å), and Si VIII (1445 Å) support our previous study. In this case, the trend of increasing temperature begins at a mass-per-charge number of 3. A qualitative explanation based on ion-cyclotron-resonance heating within linear kinetic theory is suggested.     

Four educational programs in Space Life Sciences.

Four different educational programs impacting Space Life Sciences are described: the NASA/USRA Advanced Design Program, the NASA Specialized Center of Research and Training (NSCORT) Program, the Centers for the Commercial Development of Space (CCDS) Program, and the NASA Graduate Research Fellow Program. Each program makes somewhat different demands on the students engaged in them. Each program, at the University of Colorado, involves Space Life Sciences training. While the Graduate Student Research Fellow and NSCORT Programs are discipline oriented, the Advanced Design and CCDS Programs are focused on design, technologies and applications. Clearly, the "training paradigms" differ for these educational endeavors. But, these paradigms can be made to mutually facilitate enthusiasm and motivation. Discipline-oriented academic programs, ideally, must be flexible enough to accommodate the emergent cross-disciplinary needs of Space Life Sciences students. Models for such flexibility and resultant student performance levels are discussed based upon actual academic and professional records.     

Status and Perspectives in Protective Design

Starting with an introduction into the field of hypervelocity impacts, an overview over current research in the area of protection against space debris is given. Trends and strategies to further develop know-how in protection technology are then discussed. One purpose is to demonstrate that improvements in shield efficiency can be expected. To achieve this aim, a strategy is outlined which tries to avoid the adjustment of numerical and material parameters by fits to penetration experiments. Instead, it is suggested to determine material parameters from carefully selected laboratory tests, covering a broad range of strains, strain rates and stress states. Knowledge of the dynamic material behaviour can then be used for the development of new shield concepts by means of numerical simulation.     

Theoretical performance analysis of electrochromic radiators for space suit thermal control

Variable emissivity electrochromics have been proposed as an enabling technology for integrating a radiator capability into a space suit in order to augment or replace the traditional means of heat rejection achieved via water sublimation. Thermal analysis was performed to establish design trade spaces and to provide operational guidelines and performance specifications for electrochromic technology development. Based on using the available surface area of an entire space suit as a radiator and the projected infrared emissivity modulation capability of state-of-the-art electrochromic material, the proposed application for space suit heat rejection suggests the potential exists to reduce or eliminate reliance on water consumption for thermal control within a defined range of metabolic and environmental boundary conditions.     

Effects of lunar and mars dust simulants on HaCaT keratinocytes and CHO-K1 fibroblasts

Exposure to lunar dust during Apollo missions resulted in occasional reports of ocular, respiratory and dermal irritations which showed that lunar dust has a risk potential for human health. This is caused by its high reactivity as well as its small size, leading to a wide distribution also inside habitats. Hence, detailed information regarding effects of extraterrestrial lunar dusts on human health is required to best support future missions to moon, mars or other destinations. In this study, we used several methods to assess the specific effects of extraterrestrial dusts onto mammalian skin by exposing HaCaT keratinocytes and CHO-K1 fibroblasts to dusts simulating lunar or mars soils. These particular cell types were chosen because the skin protects the human body from potentially harmful substances and because a well orchestrated program ensures proper wound healing. Keratinocytes and fibroblasts were exposed to the dusts for different durations of time and their effects on morphology and viability of the cells were determined. Cytotoxicity was measured using the MTT assay and by monitoring culture impedance, while phalloidin staining of the actin cytoskeleton was performed to address structural integrity of the cells which was also investigated by propidium iodide intake. It was found that the effects of the two types of dust simulants on the different features of both cell lines varied to a considerable extent. Moreover, proliferation of HaCaT keratinocytes, as analyzed by Ki67 labeling, was suppressed in sub-confluent cultures exposed to lunar dust simulant. Furthermore, experimental evidence is provided for a delay in regeneration of keratinocyte monolayers from scratch-wounding when exposed to lunar dust simulant. The obtained results will facilitate further investigations of dust exposure during wound healing and will ease risk assessment studies e.g., for lunar lander approaches. The investigations will help to determine safety measures to be taken during extraterrestrial expeditions in order to minimize risks to human health associated with exposure of human skin to dust contaminants.     

Ground-to-satellite laser communication experiments

Ground-to-satellite laser communication experiments between the optical ground station located in Koganei, central Tokyo, and a low earth orbit (LEO) satellite were jointly performed by the Japan Aerospace Exploration Agency and the National Institute of Information and Communications Technology. In 18 trials during three non-consecutive months, the satellite was acquired and tracked 61 % of the time, when clear or partly-clear conditions were predominant. The optical link was maintained for about 6 minutes when the satellite was visible in spite of the high angular velocity of the satellite. In 3 of the 18 trials, the link was not interrupted due to clouds during the six-minute transit. The failures (39% of the time) occurred when cloudy or rainy conditions were predominant. Fluctuation in the uplink received signal power was minimized by using multiple laser beam transmissions. The measured uplink and downlink bit error ratios were 10^-7-10^-4. These results demonstrate the applicability of free-space laser communication for not only geostationary earth orbit-LEO optical links but also ground-to-LEO optical links.     

Self-instructed condensation of amino acids into polymers

In contemporary cells biological information is largely stored in nucleic acids. Therefore, a prerequisite in many theories on the origin of cellular life is the pre-existance of self-replicating polynucleotides that had to be formed by abiotic processes on the prebiotic Earth. It is usually assumed that the spontaneous synthesis of a self-replicating polynucleotide could take place readily. However, serious stereochemical obstacles exist which make such a synthesis extremely improbable. Amino acids on the other hand, which are abundantly formed in prebiotic simulation experiments, are relatively easily polymerized to macromolecules (protoproteins) that share with modern proteins many properties: e.g., definable non-random structure, selected amino acid sequences, enzyme-like activities and self-assembly into supramolecular structures. Prebiotic polyamino acids are therefore regarded by some scientists, including the present author, as the first informational macromolecules. The origin of this information is the chemical reactivity of the various prebiotic amino acids and their chemical response to their environment. The first informational polynucleotides were likely formed by a polynucleotide polymerase activity of prebiotic protoproteins. A contemporary model for this process is seen, e.g., in the activity of template-free Qβ-replicase.