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Density of gadolinium oxide in its liquid phase was measured using a containerless technique under microgravity environment in the International Space Station (ISS). An electrostatically levitated sample was melted using high power semiconductor lasers. Pictures of a molten spherical sample were analyzed and corresponding volumes were obtained as afunction of temperature. After weighing the returned sample mass, the density of the Gd2O3 was found to be 7240 kg/m3 at its melting temperature (Tm = 2693 K).

It can be very challenging to assess the thermophysical properties of melts at temperatures higher than 2000°C, due to chemical reactions between the molten samples and their containers. To overcome this problem, containerless techniques based on electromagnetic, 1,2 aerodynamic, 3,4 or electrostatic 5 levitation have been developed. In the case of electrostatic levitation, the Coulomb force between a charged sample and surrounding electrodes is used to control the sample position. Following the development of several key technologies necessary for stable sample positioning and scientific observations, [6][7][8][9] the Electrostatic Levitation Furnace (ELF) was installed in the International Space Station (ISS) 10 to allow the analysis of containerless materials under microgravity conditions. Because it is difficult to provide a sufficient charge to the majority of oxides such that these materials will levitate under the standard gravitational force, a microgravity environment provides an ideal opportunity to perform experiments. Thus, a combination of laser heating and thermophysical property measurements has been employed in conjunction with the ISS-ELF to determine the

Very lightweight mirror will be required in the near future for both astronomical and earth science/observation missions.Silicon carbide is becoming one of the major materials applied especially to large and/or light space-borne optics, such as Herschel, GAIA, and SPICA. On the other hand, the technology of highly accurate optical measurement of large telescopes, especially in visible wavelength or cryogenic circumstances is also indispensable to realize such space-borne telescopes and hence the successful missions.We have manufactured a very lightweight =800mm mirror made of carbon reinforced silicon carbide composite that can be used to evaluate the homogeneity of the mirror substrate and to master and establish the ground testing method and techniques by assembling it as the primary mirror into an optical system. All other parts of the optics model are also made of the same material as the primary mirror.The composite material was assumed to be homogeneous from the mechanical tests of samples cut out from the various areas of the 800mm mirror green-body and the cryogenic optical measurement of the mirror surface deformation of a 160mm sample mirror that is also made from the same green-body as the 800mm mirror.The circumstance and condition of the optical testing facility has been confirmed to be capable for the highly precise optical measurements of large optical systems of horizontal light axis configuration.Stitching measurement method and the algorithm for analysis of the measurement is also under study.

Space-borne large optics will be required in future missions for astronomy and earth observations. In order to realize large-optics missions, JAXA has started the study of the ground measurement techniques of large optics. The 6m diameter radiometer thermal vacuum chamber (6m chamber) at Tsukuba Space Center will be used for tests of JAXA's future large-optics missions like Space Infrared Telescope for Cosmology and Astrophysics (SPICA). We measured the vibration environment of the 6m chamber for the feasibility study of precise optical measurement. We placed a test mirror inside the chamber and measured the surface figures of the mirror from outside the chamber with a high-speed interferometer, while the chamber was being vacuum-pumped and cooled by liquid nitrogen; we also directly measured the vibrational levels with accelerometers concurrently. The measurements were performed for each phase of the chamber system operation including pumping and cooling processes. This paper presents the results about optical measurement under the vibration environment on the 6m chamber. We confirm that the vibrations from pumps and shroud have negligible effects on optical measurements owing to a vibration isolation system in the 6m chamber.

The Advanced Land Observing Satellite-2 (ALOS-2) carries the state-of-the-art L-band Synthetic Aperture Radar (SAR) called PALSAR-2 which succeeds to the ALOS / PALSAR. PALSAR-2 has an enhanced performance in both high resolution and wide swath compared to PALSAR. It will allow comprehensive monitoring of disasters. Wider bandwidth and shorter revisit time will give better conference for interferometry SAR (INSAR) data analysis such as crustal deformation and deforestation.ALOS-2 was launched on 24th May 2014, and has been completed the initial functional verifications of onboard components and systems. This paper describes the initial operation and checkout results including the comparison with the previous SAR satellite image and the disaster monitoring. Some key features of orbit control and determination to improve the coherency of the repeat-pass INSAR observation are evaluated.