A material with a novel structure combines a material that is transmissive of radio waves, such as a widely used glass fiber-reinforced plastic (GFRP), with a radio wave shutter that can be controlled to reflect or transmit radio waves. When this new material is employed in a radome, the radome can be used as an active substitute for the reflector of a parabolic antenna. As a result, a parabolic antenna reflector is unnecessary; just a radome and a primary feed may operate as a parabolic antenna. This means radio waves can be emitted in any desired direction. Accordingly, structural components of a parabolic antenna, such as a main reflector and a supporting structure, can be omitted and the burden on a driving mechanism can be reduced. In the radio wave shutter, reverse voltages are applied to varactor diodes that are connected in series along equidistantly spaced parallel wires, switching the varactor reactances between short-circuit states and open-circuit states. In this manner, the radome is configured to be reflective in certain directions and to be transmissive in directions in which radio waves should be emitted. Because varactors are controlled by reverse biases, power consumption can be kept small. In addition, the bias directions of the varactors are alternated; consequently, the voltages of a whole set of varactors may be controlled with a voltage sufficient for control of a single varactor. Therefore, high voltage is not required even when a radio wave shutter with a large area is formed.
HAYABUSA, launched May 2003, is the first Japanese spacecraft to explore the small asteroid Itokawa. HAYABUSA had rendezvous Itokawa in three month in 2005 and touched down it twice to sample the material from it. LIDAR is a one of important navigation sensor to measure the distance between HAYABUSA and Itokawa from 50km to 50m. LIDAR operated in the three months and was estimated to have shot more than 4 million laser pulses and had supplied the ranging data to spacecraft navigation system to approach Itokawa down to 30 m.
KEYWORDS: Calibration, Fourier transforms, Signal to noise ratio, Sensors, Polarization, Short wave infrared radiation, Black bodies, Clouds, Satellites, Pulmonary function tests
TANSO-FTS (Thermal And Near infrared Sensor for carbon Observation Fourier Transform Spectrometer) and
TANSO-CAI (Cloud and Aerosol Imager) are a space-born optical sensor system mainly oriented for observation of
greenhouse gases (GHGs). TANSO will be installed on the Greenhouse gases Observing SATellite "GOSAT" and
launched in early 2009. The TANSO-FTS is a Fourier transform spectrometer which has 3 SWIR bands (0.76, 1.6 and
2.0 μm) and 1 TIR band (5.5 - 14.3 μm) for observation of scattering light and thermal radiation from the earth, mainly
focused on CO2 absorption spectra. The TANSO-CAI is an imager for detection and correction of clouds and aerosol
effects to determine GHGs quantities. The instrument characteristics of TANSO-FTS are high SNR (~300), quick
interferogram scan (1.1 ~ 4.0 s) with moderate wave-number resolution (~0.2 cm-1), and polarization measurement. Now,
integration and test of proto-flight model of TANSO have been completed. In this paper, the results of performance test
such as SNR, ILS, polarization sensitivity, etc. are described.
Design of the OCTS, a high-precision remote-sensing instrument for NASDA's Advanced Earth Observing Satellite (ADEOS) for simultaneous measurements of the ocean color and sea-surface temperatures, is presented. The OCTS uses a rotating mirror to scan a swath of the earth 1400 km wide from sun-synchronous orbit at 800 km altitude. It is planned to be placed into orbit in 1995 to provide 3 Mbps image data for visible to thermal infrared spectral range, in 12 bands.
Conference Committee Involvement (1)
Material Technologies and Applications to Optics, Structures, Components, and Sub-Systems IV
12 August 2019 | San Diego, California, United States
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