The Kaguya Mission Overview

The Japanese lunar orbiter Kaguya (SELENE) was successfully launched by an H2A rocket on September 14, 2007. On October 4, 2007, after passing through a phasing orbit 2.5 times around the Earth, Kaguya was inserted into a large elliptical orbit circling the Moon. After the apolune altitude was lowered, Kaguya reached its nominal 100 km circular polar observation orbit on October 19. During the process of realizing the nominal orbit, two subsatellites Okina (Rstar) and Ouna (Vstar) were released into elliptical orbits with 2400 km and 800 km apolune, respectively; both elliptical orbits had 100 km perilunes. After the functionality of bus system was verified, four radar antennas and a magnetometer boom were extended, and a plasma imager was deployed. Acquisition of scientific data was carried out for 10 months of nominal mission that began in mid-December 2007. During the 8-month extended mission, magnetic fields and gamma-rays from lower orbits were measured; in addition to this, low-altitude observations were carried out using a Terrain Camera, a Multiband Imager, and an HDTV camera. New data pertaining to an intense magnetic anomaly and GRS data with higher spatial resolution were acquired to study magnetism and the elemental distribution of the Moon. After some orbital maneuvers were performed by using the saved fuel, the Kaguya spacecraft finally impacted on the southeast part of the Moon. The Kaguya team has archived the initial science data, and since November 2, 2009, the data has been made available to public, and can be accessed at the Kaguya homepage of JAXA. The team continues to also study and publish initial results in international journals. Science purposes of the mission and onboard instruments including initial science results are described in this overview.     

Mercury Ion Analyzer (MIA) onboard Mercury Magnetospheric Orbiter: MMO

The Mercury Magnetopsheric Orbiter (MMO) is one of the spacecraft of the BepiColombo mission; the mission is scheduled for launch in 2014 and plans to revisit Mercury with modern instrumentation. MMO is to elucidate the detailed plasma structure and dynamics around Mercury, one of the least-explored planets in our solar system. The Mercury Plasma Particle Experiment (MPPE) on board MMO is a comprehensive instrument package for plasma, high-energy particle, and energetic neutral particle atom measurements. The Mercury Ion Analyzer (MIA) is one of the plasma instruments of MPPE, and measures the three dimensional velocity distribution of low-energy ions (from 5 eV to 30 keV) by using a top-hat electrostatic analyzer for half a spin period (2 s). By combining both the mechanical and electrical sensitivity controls, MIA has a wide dynamic range of count rates for the proton flux expected around Mercury, which ranges from 10⁶ to 10¹² cm⁻² s⁻¹ str⁻¹ keV⁻¹, in the solar wind between 0.3 and 0.47 AU from the sun, and in both the hot and cold plasma sheet of Mercury’s magnetosphere. The geometrical factor of MIA is variable, ranging from 1.0 × 10⁻⁷ cm² str keV/keV for large fluxes of solar wind ions to 4.7 × 10⁻⁴ cm² str keV/keV for small fluxes of magnetospheric ions. The entrance grid used for the mechanical sensitivity control of incident ions also work to significantly reduce the contamination of solar UV radiation, whose intensity is about 10 times larger than that around Earth’s orbit.     

海南地区电离层不规则体纬向漂移速度的观测和研究

根据中国海南富克(19.3°N,109.1°E)三点GPS观测系统2007年3月至11月的观测数据,利用互相关方法分析了三站闪烁信号的时间延迟,得出了不规则体纬向漂移的基本特征.在中国海南地区,闪烁主要发生在春秋季节,夜间不规则体的纬向漂移速度以东向为主,大小在50～150 m/s之间;平均东向漂移速度随时间呈下降趋势.另外,在闪烁刚发生时,不规则体纬向速度起伏较大,这可能与不规则体的随机起伏以及等离子体泡产生时垂直速度较大有关.中国海南地区不规则体纬向漂移速度的这些基本特征与低纬其他地区的测量结果较为一致.     

Characterization of complex organic compounds formed in simulated planetary atmospheres by the action of high energy particles.

A wide variety of organic compounds, which are not simple organics but also complex organics, have been found in planets and comets. We reported that complex organics was formed in simulated planetary atmospheres by the action of high energy particles. Here we characterized the experimental products by using chromatographic and mass spectrometric techniques. A gaseous mixture of CO, N2 and H2O was irradiated with high energy protons (major components of cosmic rays). Water-soluble non-volatile substances, which gave amino acids after acid-hydrolysis, were characterized by HPLC and mass spectrometry. Major part of the products were complex compounds with molecular weight of several hundreds. Amino acid precursors were produced even when no water was incorporated with the starting materials. It was suggested that complex molecules including amino acid precursors were formed not in solution from simple molecules like HCN, but directly in gaseous phase.     

Ballooning activities in Japan

The Scientific Balloon Center of ISAS/JAXA has carried out two balloon campaigns at Sanriku, Iwate, Japan every year. Ten to twelve balloon vehicles are launched annually for scientific and engineering experiments. Since 2005, a Brazilian balloon campaign has also been conducted in cooperation with INPE. In the 2006 Brazilian campaign, large and heavy payloads up to 1500 kg for astronomy will be launched. New generation balloons, such as super-pressure balloons and high-altitude balloons with ultra-thin films, are being developed. The current status and prospect of the Japanese scientific ballooning are discussed.     

A low cost steerable radio-telescope

We present the technical characteristics of a low-cost radio telescope for solar/non solar observations at decimetric (1200–1700 MHz) and centimetric (2700 and 5000 MHz) wavelengths known as Brazilian Decimetric Array (BDA). The technical specifications of the antenna, tracking system, log-periodic feed, preamplifier and the frequency-synthesised receiver with a Single Side Band (SSB) video output of 2.5 MHz are given.     

The effect of gravity on surface temperature and net photosynthetic rate of plant leaves.

To clarify the effects of gravity on heat/gas exchange between plant leaves and the ambient air, the leaf temperatures and net photosynthetic rates of plant leaves were evaluated at 0.01, 1.0, 1.5 and 2.0 G of 20 seconds each during a parabolic airplane flight. Thermal images of leaves were captured using infrared thermography at an air temperature of 26 degrees C, a relative humidity of 15% and an irradiance of 260 W m-2. The net photosynthetic rates were determined by using a chamber method with an infrared gas analyzer at an air temperature of 20 degrees C, a relative humidity of 50% and a photosynthetic photon flux of 0.5 mmol m-2 s-1. The mean leaf temperature increased by 1 degree C and the net photosynthetic rate decreased by 13% with decreasing gravity levels from 1.0 to 0.01 G. The leaf temperature decreased by 0.5 degree C and the net photosynthetic rate increased by 7% with increasing gravity levels from 1.0 to 2.0 G. Heat/gas exchanges between leaves and the ambient air were more retarded at lower gravity levels. A restricted free air convection under microgravity conditions in space would limit plant growth by retarding heat and gas exchanges between leaves and the ambient air.     

Ground performance of air conditioning and water recycle system for a Space Plant Box.

Researchers from 5 Japanese universities have developed a plant growth facility (Space Plant Box) for seed to seed experiments under microgravity. The breadboard model of the Space Plant Box was fabricated by assembling subsystems developed for microgravity. The subsystems include air conditioning and water recycle system, air circulation system, water and nutrient delivery system, lighting system and plant monitoring system. The air conditioning and water recycle system is simply composed of a single heat exchanger, two fans and hydrophilic fibrous strings. The strings allow water movement from the cooler fin in the Cooling Box to root supporting materials in the Plant Growth Chamber driven by water potential deficit. Relative humidity in the Plant Growth Chamber can be changed over a wide range by controlling the ratio of latent heat exchange to sensible heat exchange on the cooling fin of the heat exchanger. The transpiration rate was successfully measured by circulating air inside the Plant Growth Chamber only. Most water was recycled and a small amount of water needed to be added from the outside. The simple, air conditioning and water recycle system for the Space Plant Box showed good performance through a barley (Hordeum vulgare L.) growth experiment.     

Geomagnetic pulsations

Conclusion In writing this review paper the author has been aware that although the present international classification on geomagnetic pulsations (see Table I) had been really useful for several years since the Berkeley Meeting, it seems unsuitable for the up-to-date pulsation study. This is mainly due to the fact that it depends only on the period and waveform of the pulsations. For example, (1) occurrence of PP type of Pc1 even in the international Pc3 range (Heacock, 1966), (2) PP and CE getting mixed in a common period band (cf. 2.7), (3) similar mixing tendency of Pc3 with Pc4 (cf. 3.3 or Figure 21), (4) subtypes of Pi pulsations having common period ranges but different source mechanisms, (5) existence of various types of pulsations which can be classified neither to Pc nor to Pi (cf. Section 6), and so on. Hence the author feels that a new pulsation classification based on physical image on the occurrence models is really needed now.According to the international definition which has a period range of pulsations from 0.2 (5 Hz) to 600 sec, a part of the following electromagnetic field fluctuations called ELF emissions and ELF whistlers should belong to geomagnetic pulsations. ELF emissions are at times observed near 4 Hz and 9 Hz. They are so termed because of the difference between these frequencies and the Schumann resonance frequencies of 8 and 14 Hz (Yanagihara and Shimizu, 1969; Polk, 1969). Another type, ELF whistlers, exhibit either rising, falling or fluctuating tones from about 2 Hz to probably a few tens of Hz (Duffus, Nasmyth et al., 1958; Yamashita, 1967; Glangeaud, 1967; Yanagihara and Shimizu, 1969). In this review paper, however, both ELF emissions and whistlers have not been reviewed, since most of these seem to be out of the international frequency range so far as present observational knowledge is concerned. Some of the Pc6 and Dp2, involved in the international period range of pulsations, have also not been commented on, but the reader is advised to refer to Herron (1967) and Nishida (1968), respectively, for more detail.It has been frequently pointed out in this paper that latitudinal dependence of pulsation amplitude is one of the most important clues for seeking the model of excitation and propagation of HM and EM waves, but that this dependence has not been precisely obtained so far owing to the difference in geomagnetic longitude of the pulsation stations (for example, see Figure 40). Cooperative observations based on standardized magnetometers are eagerly desired at stations which are densely arranged along the same magnetic meridian, even if the observation is temporal.As already reviewed, various conflicting models have been proposed for each type of pulsation. On the occurrence of pc's, for example, there are two main conflicting models. In the first model, Pc2, 3, and 4 (Troitskaya, 1967; Patel and Hastings, 1968; and others) or Pc3 and 4 (Radoski and Carovillano, 1966) are related to one and the same resonance system and the difference in the type of these pc's is attributed to an effect of geomagnetic activity on the size of this system. In the second model, Pc2, 3, 4 and 5 are related to three or four different resonant systems (Jacobs and Sinno, 1960b; Hirasawa and Nagata, 1966; Kato, Mori et al., 1968; and others). Most of the conflict among such models seems to be removable by combining more thorough theoretical studies and correct dynamic spectrum analyses of the data at the polar region, auroral zone, sub-auroral zone, and middle and low latitudes, for various geomagnetic disturbance conditions.