Yoshisada Takizawa

The SELENE mission: Goals and status

Abstract SELENE (Selenological and Engineering Explorer) mission is planned in 2005 for lunar science and technology development. The mission will consist of a main orbiting satellite at about 100 km altitude in near-polar circular orbit and two subsatellites in elliptical orbits with apolunes at 2400 km and 800 km. The scientific objectives of the mission are: 1) study of the origin and evolution of the Moon, 2) measurement of the lunar environment, and 3) observation of the solar-terrestrial plasma environment. SELENE will carry 14 scientific instruments for mapping of lunar topography and surface composition, measurement of the magnetic fields, and observation of the lunar and solar-terrestrial plasma environment. The mission period will be one year. If extra fuel is available, the mission will be extended.

The system concept of SELENE

Abstract SELENE, the first ISAS & NASDA joint mission to the Moon, will be launched by H-IIA rocket in 2003. The original system concept of SELENE was studied in 1996, and a revised concept was studied aiming at large cost reduction in 1997. This paper presents the result of the conceptual study, including the mission outline, and the spacecraft design.

The selene project and the following lunar mission

Abstract The SELENE (SELenological and Engineering Explorer) project is the NASDAs first joint lunar mission with ISAS which is planned to be launched in 2003 by Japanese H-IIA launch vehicle. The major objectives of the SELENE project are researches of lunar science and feasibility of lunar utilization by the global mapping from a low lunar orbit, as well as the development of key technologies for the lunar exploration such as the soft landing technology. SELENE consists of 2 satellites, a main polar orbiter with a propulsion/landing module and a small relay satellite. The main orbiter will be inserted into 100 km altitude polar circular orbit for its 1-year mapping mission. About a dozen of scientific instruments on the main orbiter are used for the extensive global mapping of lunar surface and lunar-terrestrial science. Far-side gravimetry is implemented by the relay satellite to measure 4 way range rate from the ground station to the main orbiter. After its 1-year observation from the low lunar orbit, the propulsion/landing module will be separated to implement the soft landing experiment to verify its technology. After its successful landing on the nearside of the moon, lunar gravimetry and selenodecy in high resolution will be implemented by means of differential VLBI method with a radio source instrument on the propulsion/landing module and the relay satellite. Now, the next Lunar mission, called SELENE-2nd is being studied in the same framework of ISAS/NASDA joint program. SELENE-2nd will perform lunar science on the surface of the Moon, which will provide the more detailed data to solve the origin and evolution of the Moon in conjunction with the data obtained by SELENE. SELENE-2nd will also give the opportunity for the development of key technologies such as survival technology and traverse technology necessary for the future activities on the Moon. This paper describes the current status of SELENE including the result of phase-B study, and introduce one of the options of SELENE-2nd concept.

The Result of SELENE (KAGUYA) Development and Operation~!2009-06-28~!2009-08-10~!2009-10-01~!

Japan’s first large lunar explorer was launched by the H-IIA rocket on September 14, 2007 and had been in observation operation from December 21, 2007 to June 11, 2009(JST). This explorer named “KAGUYA (SELENE: SELenological and Engineering Explorer)” has been keenly anticipated by many countries as it represents the largest lunar exploration project of the post-Apollo program. The lunar missions that have been conducted so far have gathered a large amount of information on the Moon, but the mystery surrounding its origin and evolution remains unsolved. KAGUYA investigate the entire moon in order to obtain information on its elemental and mineralogical distribution, its geography, its surface and subsurface structure, the remnants of its magnetic field and its gravity field using the scientific observation instruments. The results are expected to lead to a better overall understanding of the Moon’s origin and evolution. Further, the environment around the Moon including plasma, the electromagnetic field and high-energy particles will also be observed. The data obtained in this way is of great scientific value and is also important information in the possibility of utilizing the Moon in the future. This paper describes the highlight of KAGUYA development and operation with some newly developed engineering achievements including a separation mechanism of sub-satellites from main orbiter as well as the latest scientific accomplishment of KAGUYA. Keyword: SELENE, KAGUYA, H-IIA, JAXA, moon, origin and evolution, ground system, GIS, YouTube, WMS, EPO. KAGUYA SATELLITE SYSTEM OVERVIEW KAGUYA consists of a main orbiter at about 100km altitude and two sub-satellites (Relay Satellite named “OKINA” and VRAD Satellite named “OUNA”) in lunar polar orbit. The main orbiter is also called as KAGUYA. The main orbiter weight at the launch is about 2.9 tons and the size of its main body is 2.1m 2.1m 4.8m. This satellite is 3 axis stabilized and the panel (+Z panel) on which mission *Address correspondence to this author at the SELENE Project, Japan Aerospace Exploration Agency, Tsukuba, 305-8505, Japan; E-mail: sobue.shinichi@jaxa.jp instruments heads are installed is pointed to the gravity center of the Moon. About 3.5 kilo watt is the maximum power produced by a solar paddle. The surface of the KAGUYA is covered with the black color conductive MLI (multi-layer thermal insulators) for conductivity requirement of plasma observation instrument (PACE). The on-orbit configuration of the Main Orbiter is shown in Fig. (1) [1-3]. KAGUYA MISSION PROFILE The Lunar transfer orbit which contributes to reduction of mission risk via two phasing loops around the Earth was adopted. KAGUYA was inserted into a polar elliptical orbit at a perilune altitude of 100 km of lunar. The two subThe Result of SELENE (KAGUYA) Development and Operation Recent Patents on Space Technology, 2009, Volume 1 13 satellites (OKINA and OUNA) were separated from the main orbiter at an apolune of 2,400 km and 800 km respectively. Finally the main orbiter reached the circular orbit at about 100 km altitude and the inclination of polar circular orbit is 90 deg. The apolune altitude of OKINA is determined to measure the gravity field anomaly on the far side of the Moon through relaying the Main orbiter s-band signal effectively. The apolune altitude of OUNA is selected for the low order gravity model coefficient measurements using radio sources on the OKINA and OUNA by VLBI method. When OKINA and OUNA separating from the main orbiter, the spin rotation power were added. This subsatellite separation mechanism which gives the rotational and the translational force simultaneously was originally developed for JAXA’s micro-lab satellite. To consider power generation, octagonal prism shape was selected for subsatellites. All faces of satellite are covered with the solar cells, and each sell produces about 70 watt powers. KAGUYA mission profile is shown in Fig. (2). OKINA was impacted to the far side of the Moon on February 11, 2009 and gravity anomaly observation at the far side of the Moon was successful completed. Fig. (1). The on-orbit configuration of the main orbiter. Lift off Separation from H -IIA Rate Dumping Solar Array Paddle Deployment Sun/Star Capture, High Gain Antenna Deployment Altitude Control of Perigee Lunar Elliptical Orbit Insertion Altitude of Perilune about 100 km

Flight Trajectory and Control System of SELenological and Engineering Explorer "KAGUYA" mission to the Moon

KAGUYA (SELENE), launched on September 14, 2007, is Japan’s first full-scale lunar explorer. The primary objectives of KAGUYA are the acquisition of scientific data related to the lunar origin and evolution and the development of technologies for future lunar exploration. A major challenge for the KAGUYA mission is reliable and robust lunar orbit insertion under various constraints. After intensive discussions and tradeoff studies, we ultimately selected a phasing lunar transfer orbit with two loops as the KAGUYA lunar transfer orbit. We developed a method for parameterized rocket trajectory by the celestial declination of the Moon to inject KAGUYA into the lunar transfer orbit and designed KAGUYA’s phasing lunar transfer orbit and orbital maneuver plan to be robust against anomalies. This paper presents the KAGUYA’s trajectory design and orbital maneuver plan, describes KAGUYA’s orbital and attitude control system, and explains KAGUYA’s flight results during lunar transfer orbit and lunar orbit injection.

Development scenario of H-II orbiting plane, hope

Abstract As the concept and the utilization plan of JEM become clear, the necessity of the autonomous transportation system becomes to be recognized in Japan. Meanwhile, NASDA has been developing the H-II launch vehicle which is capable of meeting requirements for larger payloads in the 1990s. So, it is important to study about the recovery system and describe the concept and the development scenario. As the results of the study about the long range plan, HOPE has been chosen as the most reasonable system which is to be developed at the first step. The main reasons of the choice are as follows; • — The system shall meet demands of near future space retrieval transportation for executing autonomous space activities. • — Through the development of the system, the technologies applicable to the future systems shall be established as much as possible. • — The system shall be based on the state of the art. NASDA has also conducted the conceptual case study of the winged return vehicle. The parameters of the case study were, • — The total weight of the vehicle • — Manned or un-manned • — With or without reusable upper stage propulsion system • — With or without jet engines for reliable landing This paper also describes the system concept of HOPE and related key technologies.