SELENE
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This article or section documents a current or recent spaceflight. Details may change as the mission progresses. |
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| Kaguya (かぐや?) (SELENE) | |
 The mission mark of KAGUYA |
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| Organization | JAXA |
|---|---|
| Mission type | Orbiter |
| Satellite of | Moon |
| Launch date | 01:31:01, 14 September 2007 UTC |
| Launch vehicle | H-IIA |
| NSSDC ID | 2007-039A |
| Webpage | SELENE page |
| Mass | 2914 kg (Main Orbiter, launch mass) |
| Power | 3486 W |
| Orbital elements | |
| Inclination | 90° |
| Orbital period | 2h |
| Apoapsis | 100 km |
| Periapsis | 100 km |
SELENE (Ancient Greek: Σελήνη, moon), better known in Japan by its nickname Kaguya (かぐや?), is the second Japanese lunar orbiter spacecraft.[1] Produced by the Institute of Space and Astronautical Science and NASDA (both organizations that are now part of the Japan Aerospace Exploration Agency, or JAXA), the spacecraft was launched September 14, 2007.
The name stands for Selenological and Engineering Explorer; Selene was a lunar deity in Greek mythology. The orbiter's nickname, Kaguya, which was selected by the general public, derives from the name of a lunar princess in the ancient Japanese folktale The Tale of the Bamboo Cutter.[2] After the successful release of its sub-satellites Rstar and Vstar, they were named Okina and Ouna, also from folklore.[3]
SELENE comes as part of a renewed interest in lunar exploration, being "the largest lunar mission since the Apollo program",[4] and following up on Japan's first lunar probe, Hagoromo, launched in 1990.[1][5] China has launched the Chang'e 1 lunar explorer on October 24, 2007, with India's Chandrayaan and the United States Lunar Reconnaissance Orbiter following in 2008. The United States, European countries, Russia, Japan and China are planning future manned lunar exploration missions or base construction on the moon for the year 2018 or later.[citation needed]
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[edit] Mission objectives
The main scientific objectives of the mission are:
- Study the origins of the Moon and its geologic evolution
- Obtain information about the lunar surface environment
- Perform radio science on lunar orbit
[edit] Launch
SELENE launched at 01:31:01, September 14, 2007 UTC on an H-IIA (Model H2A2022) carrier rocket from Tanegashima Space Center into a 281.55 km (perigee) / 232960 km (apogee) geocentric parking orbit.[6] [7] The total launch mass was 3020 kg.[8]
The SELENE mission was originally scheduled to launch in 2003, but rocket failures on another mission and technical difficulties delayed the launch until 2007.[9] Launch was planned for August 16, 2007, but was postponed due to the discovery that some electronic components were installed incorrectly.[10]
[edit] Lunar operations
On October 3, it reached the moon and entered an initial 101 by 11741 km polar orbit.[11] On October 9, the relay satellite was released to an approximately 100 by 2400 km orbit, and on October 12 the VLBI satellite was released to an approximately 100 by 800 km orbit.[3] Finally, by October 19, the orbiter moved to an approximately 100 km circular orbit.[12] The nominal operation of the mission is one year, with extension if possible.
JAXA announced on October 31, 2007 that Kaguya deployed its Lunar Magnetometer, Lunar Radar Sounder, as well as the Earth-looking Upper Atmosphere and Plasma Imager.
JAXA announced on December 21, 2007 that the operation mode of the lunar explorer, KAGUYA, was shifted to regular operations from its initial verification on December 21, 2007 (Japan Standard Time) as they were able to acquire satisfactory verification results for all fifteen observation missions.
[edit] Design
There are three separate units comprising the spacecraft.
[edit] Main orbiter
The main orbiter is a rectangular box measuring about 2.1 m by 4.2 m, with a launch mass of about 2914 kg.[8]
- Mass: 2914 kg
- Size: 2.1 x 2.1 x 4.8 m
- Attitude control: Three-axis stabilized
- Power: 3.5 kW (Max.)
- Mission period: 1 year
- Mission orbit: Circular orbit
- Altitude 100 km
- Inclination 90 degree
[edit] Okina (small relay satellite)
Okina, a small relay satellite (formerly called Rstar) and Ouna, a VLBI satellite (formerly called Vstar) are both octagonal prisms. The relay satellite relays the radio wave from the Earth to the orbiter and also the opposite direction, when the orbiter is hidden behind the moon, to measure the Doppler shift.
- Mass: 53 kg[8]
- Size: 1.0 x 1.0 x 0.65 m
- Attitude control: spin-stabilized
- Power: 70 W
- Orbit (initial orbit):
- Elliptical orbit (100 km x 2400 km)
- Inclination 90 degrees
[edit] Ouna (VLBI satellite)
The Vstar (Very Long Baseline Interferometry satellite) will be used to measure the moon's gravity field, especially of the lunar limb area, where the Doppler shift method cannot be used.
- Mass: 53 kg
- Size: 1.0 x 1.0 x 0.65 m
- Attitude control: spin-stabilized
- Power: 70 W
- Orbit (initial orbit):
- Elliptical orbit (100 km x 800 km)
- Inclination 90 degrees
[edit] Payload
SELENE carries 13 scientific instruments, including imagers, a radar sounder, a laser altimeter, an X-ray fluorescence spectrometer and a gamma ray spectrometer. Their objectives are "to obtain scientific data of the lunar origin and evolution and to develop the technology for the future lunar exploration", according to the official website.[13]
- Terrain camera (TC) (resolution 10 meters per pixel)[14]
- X-Ray fluorescence spectrometer (XRS)
- Lunar magnetometer (LMAG)
- Spectral profiler (SP) (resolution per pixel is 562 by 400 m)
- Multi-band imager (MI) (resolution of visible light 20 meters per pixel, near-infrared 62 meters per pixel)
- Laser altimeter (LALT)
- Lunar radar sounder (LRS)
- Gamma ray spectrometer (GRS)
- Charged particle spectrometer (CPS)
- Plasma analyzer (PACE)
- Upper atmosphere and plasma imager (UPI)
- Radio wave repeater (RSAT) aboard Okina
- Radio wave source for VLBI (VRAD) aboard Okina and Ouna
Also, an HDTV camera with 3*CCD 2.2 megapixels, one wide-angle camera and one telephoto camera are on board, primarily for public relations purposes.
Along with scientific instruments, JAXA collected names and messages to be carried on SELENE through their "Wish Upon the Moon" campaign.[15] The 412,627 names and messages collected were printed on a sheet measuring 280 mm × 160 mm, at a size of 70 µm per character. The sheet was installed under the photovoltaic modules and the cooling panels for the instruments, beneath the multi-layered insulation.[16]
[edit] References
- ^ a b "Kaguya – Another Chapter for the Lunar Saga", Red Orbit, 14 September 2007. Retrieved on 2007-09-14.
- ^ "KAGUYA" selected as SELENE's nickname. Retrieved on 2007-10-13.
- ^ a b (2007-10-12). "KAGUYA (SELENE) / Result of the Separation of the VRAD Satellite (Vstar)". Press release. Retrieved on 2007-10-13.
- ^ SELENE: The largest lunar mission since the Apollo program. Retrieved on 2008-04-21.
- ^ Hiten. NASA. Retrieved on 2007-09-14.
- ^ Emily Lakdawalla (2007-09-14). Kaguya Rockets Toward the Moon. Retrieved on 2007-09-15.
- ^ MHI / JAXA. H-IIAロケット13号機による月周回衛星「かぐや」の打上げ結果について（速報） (Japanese). Retrieved on 1997-09-19.
- ^ a b c 平成19年度夏期ロケット打ち上げおよび追跡管制計画書 (Rocket Launch and Tracking Control Plan, Summer 2007) (PDF) (Japanese). MHI / JAXA.
- ^ Japan launches first lunar probe (14 September 2007). Retrieved on 2007-09-14.
- ^ Launch Postponement of the KAGUYA (SELENE) (2007-07-20). Retrieved on 2007-08-15.
- ^ JAXA (2007-10-05). "KAGUYA (SELENE) Result of the Lunar Orbit Injection Maneuver (LOI1) - Lunar orbit injection was confirmed -". Press release. Retrieved on 2007-10-05.
- ^ かぐや/H-IIA13号機 打上げ特設サイト (Japanese). Retrieved on 2007-10-01.
- ^ Kaguya (SELENE). JAXA. Retrieved on 2007-06-25.
- ^ LISM [TC, MI, SP]. Kaguya (SELENE). JAXA. Retrieved on 2007-06-25.
- ^ The Planetary Society (2007-01-11). "Send a New Year's Message to the Moon on Japan's SELENE Mission: Buzz Aldrin, Ray Bradbury and More Have Wished Upon the Moon". Press release. Retrieved on 2007-07-14.
- ^ セレーネ「月に願いを!」(SELENE "Wish Upon the Moon!") (Japanese). JAXA (2007). Retrieved on 2007-07-14.
[edit] See also
[edit] External links
- (English) Official project site, JAXA
- (English) Official launch information site, JAXA
- SELENE Mission Profile by NASA's Solar System Exploration
- (English) SELENE overview, ISAS/JAXA
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