Takahide Mizuno

Asteroid sample and return spacecraft WSES-C has some newly-developed light weight optical sensors, in order to approach, rendezvous with, and land on the asteroid 1989ML. ONC-T is a multi-spectrum optical band camera with 8 filters, 5.7degrees x 5.7degrees FOV, and 20 arcsec/pixel resolution. It is used for scientific observation and the precise global mapping of the asteroid to select a landing point. Both ONC-W1 and W2 are wide angle camera with 60degrees x 60degrees FOV and used for autonomous guidance onboard. LIDAR is used for measurement of distance to the asteroid surface from 50 km to 50 m. LRF provides relative distance and attitude to the asteroid surface using four beams at the range less than 100 m. Four sets of FBS detect obstacle under solar cell panels to avoid unexpected collision to the surface. In this paper, after brief description of rendezvous and landing scenario, aims, requirements, and design specifications of each sensor are shown. Present status of development, function and performance test results of some prototype sensors are also reported. (C) 2002 Elsevier Science Ltd. All rights reserved.

The New Precision Radar that the Institute of Space and Astronautical Science（ISAS） developed for the tracking of the scientific-satellite launcher and sounding rockets is described. The radar has been operating since 1996 at the Kagoshima Space Center（KSC）of ISAS, of which operations conducted include trackings of three M-V rockets and numbers of sounding rockets. The key features of the New Precision Radar are（1）a 7m diameter antenna and（2）complete digital processing of the signals at IF and the after-stages. The margin of the signal detection in the secondary radar mode（beacon mode）has been improved 10 decibels from that of the old Precision Radar which ISAS had been using for long years. In the primary radar mode（skin mode）, the pulse compression with a compression ratio of 1000 has been achieved by digital techniques, and the maximum detection range has substantially been expanded.

This paper describes outline of the piggy-back satellite "INDEX" for demonstration of advanced satellite technologies as well as for observation of fine structure of aurora. Aurora observation will be carried out by three cameras(MAC) with a monochromatic UV filter. Electron and ion spectrum analyzer (ESA/ISA) will measure the particle phenomena together with the aurora hanging. INDEX satellite will be launched in 2002 by Japanese H2-A. The satellite is mainly controlled by the high-speed, fault-tolerant on-board RICS processor (three-voting system of SH-3). The attitude control is a compact system of three-axis stabilization. Although the size of INDEX is small (50Kg class), several newly-developed technologies are applied to the satellite system, including silicon-on-insulator devices, variable emittance radiator, solar-concentrated paddles, lithium-ion battery, and GPS receiver with all-sky antenna-coverage. © 2001 International Astronautical Federation. Published by Elsevier Science Lt d.

Coherent microwave and millimeter wave emission from a rotating electron beam in a circular wiggler magnetic field (circular free electron laser) has been studied. The circular wiggler, which consists of a coaxial waveguide and an azimuthally periodic magnetic field, is compact as compared with a conventional linear FEL. Tunable radiation frequency (TM coaxial waveguide mode) was observed to be typically 11-38 GHz using a mildly relativistic electron beam of energy less than 500 kV, about 150 A current and about 8 mus pulse width. The total radiation power was about 840 kW at 11.5 GHz of TM6.1.

Generation of microwave radiation from a rotating electron beam in a circular wiggler magnetic field (circular free-electron laser) has been studied. The electron beam is emitted by a velvet-covered cathode; its energy is typically 300–500 keV and its beam current is 160 A. Measured frequency, power and pulse width of the radiated microwave are 12.7 GHz, 11 kW and 500 ns, respectively. Measured frequency agrees with the theoretical prediction. The interaction between the beam mode and the traveling magnetic waveguide mode is discussed based upon the dispersion relation.

Formation of a rotating, relativistic electron beam with properties suitable for a circular free electron laser has been studied. The rotating, relativistic electron beam is generated by the method of injecting a straight-moving, hollow, relativistic electron beam (typical energy 500 keV) into a magnetic cusp. By decreasing the axial transition width of the cusp, the beam off-centering motion is suppressed and the beam current is increased by a factor of 4 (from 50 A to 200 A).