The Reusable Sounding Rocket is a fully re-usable sub-orbital sounding rocket that takes-off and lands vertically from/on the same launch site. The Reusable Sounding Rocket recovers its payload: one can make repeated use of instruments, recover samples, have a big data storage onboard, and so on. The Reusable Sounding Rocket can be launched daily. The target cost for operation is 1/10 of the existing sounding rocket, S-310. The duration of g environment is about 3 minutes. The payload bay is in the nose-cone and its volume is 0.8m in diameter and 1m in height. The maximum mass of the payload is 100kg.
Thermophysical property measurement using levitation processing in space, while expensive, has the potential for providing benchmark datasets of highest quality. Unfortunately, much of the previous historical record concentrates on data accuracy without adequately addressing precision making it hard to justify the added costs associated with developing and using microgravity facilities. Furthermore, analysis of measurement precision in the literature often does not fully distinguish the magnitude of relative contributions from both systematic and random error. This paper presents a brief review of the status of measurements for a subset of key properties that are appropriate for space investigation. From this, it is hoped that discussions are stimulated across the property measurement community to initiate development of reporting standards to better document relative variability for specific test platforms, both ground and space, to allow industry to better define the value-added for sponsoring space experimentation.
Proton exchange membrane (PEM) based unitized reversible fuel cells (URFCs) have attractive features as a key component of hydrogen utilization systems. To determine if drawbacks that do not appear in a small-scale single cell of a URFC are significant when a URFC has larger cells in a stack configuration required for commercial applications, a pilot-scale URFC system was successfully operated in both the electrolysis and fuel cell operation modes and both its overall stack performance and the performance variation between cells were measured. No significant drawbacks due to larger cells or stacking were detected in either mode. Local hydrogen pressure at the generation point during electrolysis mode and local flooding during fuel cell mode is examined based on experimental data.
The interaction between two neighboring n-decane droplets during the autoignition process in air was experimentally investigated under microgravity conditions in the drop tower Bremen. The initial droplet diameter was 0.8 mm in all experiments. Single droplets and droplet pairs with a center distance of 1, 2, 4 and 6 mm were investigated. The air temperature was varied between 650 and 850 K with an increment of 25 K. The examined pressure conditions were 0.3 and 0.5 MPa. This results in a total number of 90 drop experiments. The ignition process was observed applying the laser induced fluorescence (LIF) on formaldehyde with high temporal and spatial resolution. Both, the cool flame process and the hot flame ignition could be measured regarding induction times and the temporal and spatial evolution of the formaldehyde formation
Efficiency of observing translation and rotation of a sub-millimeter size sample at low magnetic field has considerably increased by improving the system to release small samples in microgravity (μG) area of reduced pressure. By measuring the period of rotational oscillation induced in a homogeneous field of 0.2T, anisotropy of paramagnetic susceptibility ΔχPARA was detected on a small paramagnetic crystal. By observing velocity vR of a translating grain at a position of B ~ 0, diamagnetic susceptibility χDIA is detected in a small grain. Here the position of sample stage was controlled for the purpose of releasing the samples in a μG area with small momentum. The obtained techniques to observe fieldinduced motions of sub-mm sized samples are a step forward to detect magnetization of a weakly magnetic particle of μm size.
Molecular dynamics simulations were carried out for charge-stabilized colloidal dispersions using the Sogami-Ise potential, based on general theoretical calculations of the electrostatic interaction in a macroionic solution. The molar weight of the particles was assumed to be 10000 g/mol, and the particle radius was 65 nm. The initial basic cell configuration was face-centered cubic (FCC) crystal, for which the number of particles N was 864. Periodic boundary conditions were assumed, and the cutoff length was the half of the cell length. The Gear integration method was used. An NTV ensemble was used, where V is the volume and the temperature T was 300 K. The liquid, FCC crystal and void structures were found. The obtained phase diagram is consistent with macroscopic observations and the results of Monte Carlo simulations of charge-stabilized colloidal dispersions.
In 2003 NASA astronaut Dr. D. Pettit conducted thermocapillary experiments in a thin water film (Prandtl number; Pr = 7) sustained in a circular ring onboard the International Space Station (ISS). When a section of the ring was heated, a thermocapillary flow developed from the cold region towards the hotter region. This unusual flow phenomenon (being from cold to hot) was explained by the dependency of free surface shape on the flow pattern observed in the film. However, the dependency of flow behavior on the Prandtl number was not investigated previously. Motivated by the wide range of applications of the low-Prandtl-number liquids, numerical simulations for the flow phenomena observed in the films of different shapes and Prandtl numbers were performed under zero gravity. Results have shown that in the case of low-Prandtl-number film although the flow direction remained the same, the flow velocity increased significantly. This interesting phenomenon is explained by means of the temperature gradient in the film in the y- (vertical) and θ- (circumferential) directions.
The surface tension of molten silver was measured as a function of temperature and oxygen activity, a02 , by the oscillating droplet method using electromagnetic levitation. The surface tension of molten silver was successfully measured over the very wide temperature range of 515 K. The pure state value of the surface tension was measured when a02 is lower than 5.3×10-19. The surface tension shows a boomerang shape temperature dependence at a02 of 3.2×10-5 to 2.0×10-3. The excess amount of oxygen adsorption on the molten silver was deduced from the Gibbs adsorption isotherm. The equilibrium constant, standard enthalpy, and standard entropy for the oxygen adsorption reaction on molten silver was revised, using the measurement result based on the Szyskowski model. Furthermore, the relationship between the surface tension, temperature, and a02 was also updated.
Many experiments to simulate Mars environment have been implemented around the world. In this article, we report MARS500, HI-SEAS, MDRS, Biosphere 2 and Yuegong-1 as simulations of manned Mars exploration. More than 1000 people have participated in MDRS including Japanese researchers, engineers and students. The Biosphere 2 experiment proved that it is difficult to mimic Earth’s ecosystem. Effects of microgravity and radiation during manned Mars exploration have been also examined in many experiments. The radiation detector piggybacked to the Mars rover, Curiosity, showed high level of radiation during the trip from Earth to Mars. Therefore, some measure should be taken to avoid high level of radiation exposure to astronauts.