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Up-link Laser Differential Absorption Sensing: ULDAS, shown in Fig.1, is a new method to measure green house gas concentration with earth observation satellites. Although the measurement area is restricted in only small visible area of an optical ground station, ULDAS has outstanding features as followed: - Faster: Easy to development, small size and small resource requirements to satellite system - Better: High accuracy (CO 2 observation error of weighted column is - Cheaper: Simple system, small number of parts and no special parts The flight segment of the ULDAS is able to be loaded on a marginal resource of green house effect observation satellites, such as Japanese GOSAT-series. In this paper, the feasibility study of the mission concept and field experiments are reported.

Tandem-L is a proposal for an innovative interferometric radar mission to monitor the Earth system and its intricate dynamics. Important mission objectives are global inventories of forest height and above-ground biomass, largescale measurements of Earth surface deformations due to plate tectonics, erosion and anthropogenic activities, observations of glacier movements and 3-D structure changes in land and sea ice, and the monitoring of ocean surface currents. The mission concept is based on co-flying two fully-polarimetric L-band SAR satellites in a close formation. Tandem-L employs new techniques and advanced technologies to achieve its ambitious mission goals. The feasibility of a joint DLR/JAXA mission is currently being investigated in the scope of a pre-phase A study.

A conceptual study was undertaken on earth observation missions for a satellite within the Sun-Synchronous and Medium Earth Orbit (SS-MEO). Our mission study of a MEO Satellite was performed as pioneering research into a newly utilized earth orbit that exists between the Low Earth Orbit (LEO) and the Geostationary Earth Orbit (GEO). One of the advantages of the MEO is that it delivers a wider field of view (FOV), which permits more frequent observations that are more easily obtained, in comparison with the LEO. Another advantage is that the performance demands for sensors are moderate, relative to those for the GEO. This conceptual study of earth observation missions is considered for the baseline (4184 km) orbits, focusing on optical sensors. We summarize the needs of each assumed user (products, observational frequency, and spatial resolution) related to four missions (agricultural, forest, ocean, and air pollution observations). Agricultural observation is expected to need a spatial resolution of 10 m and an observational frequency of a few times a week. As a result, required optical sensor is that with an aperture diameter of 30 cm, an f-number of 11, and a signal-to-noise ratio (S/N) of 20. It is thought that the optical sensor for the agricultural observation would be larger in comparison with the previous optical sensors used within the LEO, because the S/N and FOV are smaller. However, it was found there is a challenge to be met in terms of a compatibility with the f-number and FOV. This paper shows the results of this conceptual study and the issues raised relating to mission sensors for earth observation missions in the MEO., 資料番号: PA1410077000

The Medium Earth Orbit (MEO) offers a greater width of satellite view than the Low Earth Orbit, and a greater roximity to the Earth’s surface than the Geostationary Earth Orbit. Global positioning systems and ionospheric sounding satellites have already operated in this orbit, and the MEO will appeal to satellite missions undertaking Earth observations,communications, positioning, and scientific explorations. The Sun-Synchronous Medium Earth Orbits (SS-MEOs) used in this study enable clear and daily observations of the Earth’s surface. However, problems such as severe radiation from the Van Allen radiation belt, and the inefficiency to launch a satellite in a southwest direction, need to be resolved. This paper presents the results of early studies on SS-MEO utilization: orbital characteristics and environments, candidates for Earthobservation missions, and the feasibility of the development and launch of a satellite for operation within this orbit., 資料番号: PA1410079000