Takahide Mizuno

An accurate measurement of velocity is necessary for scientific observation using a lunar and a planetary lander that landing ambiguity is less than 100m. A landing radar is a sensor which measure an altitude and velocity of a space craft with C-band microwave pulse. This report describes that the dependance of terrain for velocity measurement and the result of field experiment using a helicopter.

We have developed a novel MEMS scanner of the laser radar for landing to the planet. The scanner has to overcome launching vibration and impact and can be used in harsh environment of the space

Miniature space GPS receivers have been developed by means of automobile-navigation technology. We expanded the frequency sweep range in order to cover large Doppler shift on orbit. The GPS receiver was modified to output pseudorange data with accurate time tag. We tested the performance in low earth orbits by means of a GPS simulator. The range error caused by the receiver is measured to be 1 meter. The position accuracy is estimated to be less than 17 meters (rms) in the low earth orbits. This GPS receiver was on-boarded on INDEX satellite, which launched in 2005. Cold start positioning was confirmed repeatedly to finish within 30 minutes on orbit. The orbit determination was performed to evaluate the random position error of GPS receiver by means of the residual error. The random error of GPS position is as large as 2 meter for PDDP=2 on orbit. These results on orbit are consistent with the simulation results in use of a GPS simulator.

This paper describes the on-orbit results and lessons learned of the small scientific satellite "INDEX" (REIMEI) for aurora observation and demonstration of advanced satellite technologies. REIMEI is a small satellite with 72kg mass, and is provided with three-axis attitude controlled capabilities for aurora observation. REIMEI was launched into a nearly sun synchronous polar orbit on Aug. 23^<rd>, 2005 (UT) from Baikonur, Kazakhstan by Dnepr rocket. REIMEI satellite functions satisfactorily on the orbit. Three axis control is achieved with accuracy of 0.05 deg. Multi-spectrum images of aurora are taken with 8Hz rate and 2 km spatial resolution to investigate the aurora physics. REIMEI is a small scientific satellite for aurora observation and advanced satellite technologies, and was launched into a nearly sun synchronous polar orbit on Aug. 23^<rd>, 2005 (UTC) from Baikonur, Kazakhstan by Dnepr rocket. REIMEI satellite functions satisfactorily on the orbit. The three-axis attitude control is achieved with accuracy of 0.05deg. REIMEI is performing the simultaneous observation of aurora images as well as particle measurements. REIMEI indicates that even a small satellite launched as a piggy-back can successfully perform the unique scientific mission purposes.

Miniature space GPS (Global Positioning System) receivers have been developed by means of automobile-navigation technology. The weight and power consumption of the GPS receiver are 35 g and 1 W, respectively. We expanded the frequency sweep range in order to cover large Doppler shift in orbit. We tested the performance in low earth orbits by means of a GPS simulator. The GSP receiver succeeded in cold start acquisition in less than 30 minutes. This GPS receiver was on-boarded on INDEX satellite launched in August 2005. The performances of cold start acquisition and position accuracy was verified in orbit.

Science experiment on the Moon with the small intelligent lander is under study. Despite of small mass badget for science instrument, short mission life without long-lived survivability, and limitation of landing site on the lunar near side, small mission can provide an opportunity for landing at the most desirable site for its objective. It will be also a good testbed of technology demonstlation for future lunar and planetary missions. We present here the small lunar lander mission and its science payload proposed.

A transmission optics system for a 2D scanning LIDAR system for a deep space explore with a MEMS mirror has been proposed. 2D scanning LIDAR that developed in ISAS/JAXA has many narrow field of views that are placed dispersion array in scanning angle at φ10°. A transmission system of 2D LIDAR has a Passive Q-SW YAG leaser as a transmitter. It shot its leaser pulse on a field of view(φ1.5mrad) of receiver system. In this result, the detection method of the MEMS mirror that is driving in 500Hz has been proposed. From experiment, we found the accuracy of the method was less than 0.5mrad.

Miniature space GPS receivers have been developed by means of automobile-navigation technology. The weight and power consumption of the GPS receiver are 35g and 1W, respectively. We expanded the frequency sweep range in order to cover large Doppler shift in orbit. We tested the performance in low earth orbits by means of a GPS simulator. The GSP receiver succeeded in cold start acquisition in less than 30 minutes. This GPS receiver was on-boarded on INDEX satellite launched in August 2005. The performances of cold start acquisition and position accuracy was verified in orbit.

LIDAR (LIght Detection And Ranging) is an important navigation sensor for the asteroid probe "HAYABUSA" to measure distance with an asteroid. Since it is carried in a planetary exploration spacecraft, the weight of LIDAR is very lightweight at 3.6kg. Furthermore, in order to realize landing missions, range finding ranges are 50km-50m. So the wide dynamic range is a big feature of this LIDAR system. The composition and basic performance of LIDAR are explained and this paper also reports the ranging data at the time of landing to asteroid ITOKAWA of the autumn of 2005.

A radar for navigation in future lunar/planetary landing missions is developed in the JAXA/ISAS. The C-band pulse radar provides not only altitude information but also relative velocity against the surface, so that the landers can perform pinpoint landing on the pre-decided place. In this paper, the landing radar overview and its technological characteristics are described with the review of scattering properties on the lunar surface. The results of the dynamic flight experiment using a helicopter are also reported.

A new precision measurement radar for launching rockets has been developed in ISAS. The channel margin has been improved about 10dB comparing the existing system by using a larger antenna and implementing digital signal processing on the receiver. The maximum radar range at skin-tracking mode has been extended by long pulse transmission and pulse compression technique. The system has already been used for tracking of the M-V rockets and others and shown the expected performance. In this paper we report the system structure, the performance, and operational results of this radar.

In this report, a design of high quality electron-gun, an optimization of a electron beam control system and an analysis of a dualplate waveguide with a grating for a Smith-Purcell FEL is described. We designed the electron-gun and the optimized electron control system by E-GUN and TRACE-3D. As a result, we obtained about 2 [mm] diameter at the center of grating in the case of electron energy 700 [keV], and the beam current 0.78 [A]. We analyzed the dispersion relation of the dualplate waveguide with the grating and designed grating to obtain the oscillation at 100 [GHz] with the second hjighermode.