SELENE
Encyclopedia
SELENE (ˈsɛlɨniː Selenological and Engineering Explorer), better known in Japan by its nickname after the legendary Japanese moon princess, was the second Japan
ese lunar
orbiter spacecraft
. Produced by the Institute of Space and Astronautical Science
(ISAS) and the National Space Development Agency (NASDA), both now part of the Japan Aerospace Exploration Agency (JAXA), the spacecraft was launched on September 14, 2007. After successfully orbiting the moon for a year and eight months, the main orbiter was intentionally crashed onto the lunar surface near the Gill
lunar crater at 18:25 UTC on June 10, 2009.
The orbiter's nickname, Kaguya, was selected by the general public. It comes from the name of a lunar princess in the ancient Japanese folktale The Tale of the Bamboo Cutter
. After their successful release, its sub-satellites, Rstar and Vstar, were named Okina and Ouna, also derived from characters in the tale.
SELENE launched on 14 September 2007 at 01:31:01 UTC on an H-IIA
(Model H2A2022) carrier rocket from Tanegashima Space Center
into a 281.55 kilometres (174.9 mi) (perigee
) / 232960 kilometres (144,755 mi) (apogee) geocentric
parking orbit
. The total launch mass was 3020 kilograms (6,658 lb).
The SELENE mission was originally scheduled to launch in 2003, but rocket failures on another mission and technical difficulties delayed the launch until 2007. Launch was planned for August 16, 2007, but was postponed when some electronic components were found to be installed incorrectly.
On October 9, the relay satellite was released into a 100 kilometre orbit, while on October 12 the VLBI satellite was released into a 100 kilometre one. Finally, by October 19, the orbiter was in a circular 100 kilometres (62.1 mi) orbit. The nominal mission duration was one year plus possible extensions.
On October 31, 2007, Kaguya deployed its Lunar Magnetometer, Lunar Radar Sounder, Earth-looking Upper Atmosphere and Plasma Imager. On December 21, 2007, Kaguya began regular operations after all fifteen observation experiments had been satisfactorily verified.
Kaguya completed the planned operation by the end of October 2008 and began extended operations planned to continue through March 2009. It would then be sent into a circular 50 kilometres (31.1 mi) orbit, and finally to a elliptical 20 kilometre one, with a controlled impact occurring by August 2009. Because of a degraded reaction wheel, the plan was changed so that on February 1, 2009, the orbit was lowered to 50 kilometres (31.1 mi) ± 20 kilometres (12.4 mi),
and impact occurred at 18:25 UTC on June 10, 2009.
radio communications between the orbiter and the Earth when the orbiter was behind the Moon. This allowed, for the first time, the direct Doppler shift measurements needed
to precisely map the gravitational field of the lunar farside; previously, the farside gravity field could only be inferred by nearside measurements. The relay satellite impacted the lunar farside near the Mineur D
crater at 19:46 JST (10:46 UTC) on February 12, 2009.
as a second way to map the Moon's gravity field. It was especially useful at the lunar limb
, where the gravitational acceleration is perpendicular to the line of sight to earth, making Doppler measurements unsuitable.
Two 2.2 megapixel CCD HDTV
camera
s, one wide-angle and one telephoto, were also on board, primarily for public relations purposes.
JAXA collected names and messages that were carried on SELENE through their "Wish Upon the Moon" campaign. 412,627 names and messages were printed on a sheet measuring 280 mm x 160 mm (11 x 6.3 in) at 70 µm
(0.0003 in) per character. The sheet was installed under the photovoltaic module
s and cooling panels beneath the multi-layered insulation.
, launched in 1990. China
launched its Chang'e 1 lunar explorer on October 24, 2007, followed by India
's 22 October 2008 launch of Chandrayaan-1 and the United States
Lunar Reconnaissance Orbiter
in June 2009. The United States, Europe
an countries (ESA), Russia
, Japan
, India and China are planning future manned lunar exploration missions or lunar outpost construction on the Moon between 2018 and 2025.
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
ese lunar
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...
orbiter spacecraft
Spacecraft
A spacecraft or spaceship is a craft or machine designed for spaceflight. Spacecraft are used for a variety of purposes, including communications, earth observation, meteorology, navigation, planetary exploration and transportation of humans and cargo....
. Produced by the Institute of Space and Astronautical Science
Institute of Space and Astronautical Science
is a Japanese national research organization of astrophysics using rockets, astronomical satellites and interplanetary probes. It is a division of Japan Aerospace Exploration Agency .- History :...
(ISAS) and the National Space Development Agency (NASDA), both now part of the Japan Aerospace Exploration Agency (JAXA), the spacecraft was launched on September 14, 2007. After successfully orbiting the moon for a year and eight months, the main orbiter was intentionally crashed onto the lunar surface near the Gill
Gill (lunar crater)
Gill is a lunar crater that is located near the southeastern limb of the Moon. Due to its proximity to the edge of the Moon as seen from the Earth, this crater is viewed nearly from the side and it can become hidden from sight due to libration. The crater lies to the southwest of the irregular Mare...
lunar crater at 18:25 UTC on June 10, 2009.
The orbiter's nickname, Kaguya, was selected by the general public. It comes from the name of a lunar princess in the ancient Japanese folktale The Tale of the Bamboo Cutter
The Tale of the Bamboo Cutter
, also known as , is a 10th century Japanese folktale. It is considered the oldest extant Japanese narrative and an early example of proto-science fiction....
. After their successful release, its sub-satellites, Rstar and Vstar, were named Okina and Ouna, also derived from characters in the tale.
Mission objectives
The main scientific objectives of the mission were to:- Study the origins of the Moon and its geologic evolution
- Obtain information about the lunar surface environmentGeology of the MoonThe geology of the Moon is quite different from that of the Earth...
- Perform radio science, especially precise measurement of the moon's gravity field
Launch
H-IIA
H-IIA is an active expendable launch system operated by Mitsubishi Heavy Industries for the Japan Aerospace Exploration Agency . The liquid-fueled H-IIA rockets have been used to launch satellites into geostationary orbit, to launch a lunar orbiting spacecraft, and to launch an interplanetary...
(Model H2A2022) carrier rocket from Tanegashima Space Center
Tanegashima Space Center
The is one of Japan's space development facilities. It is located on Tanegashima, an island located 115 km south of Kyūshū. It was established in 1969 when the National Space Development Agency of Japan was formed...
into a 281.55 kilometres (174.9 mi) (perigee
Perigee
Perigee is the point at which an object makes its closest approach to the Earth.. Often the term is used in a broader sense to define the point in an orbit where the orbiting body is closest to the body it orbits. The opposite is the apogee, the farthest or highest point.The Greek prefix "peri"...
) / 232960 kilometres (144,755 mi) (apogee) geocentric
Geocentric orbit
A geocentric orbit involves any object orbiting the Earth, such as the Moon or artificial satellites. Currently there are approximately 2,465 artificial satellites orbiting the Earth and 6,216 pieces of space debris as tracked by the Goddard Space Flight Center...
parking orbit
Parking orbit
A parking orbit is a temporary orbit used during the launch of a satellite or other space probe. A launch vehicle boosts into the parking orbit, then coasts for a while, then fires again to enter the final desired trajectory...
. The total launch mass was 3020 kilograms (6,658 lb).
The SELENE mission was originally scheduled to launch in 2003, but rocket failures on another mission and technical difficulties delayed the launch until 2007. Launch was planned for August 16, 2007, but was postponed when some electronic components were found to be installed incorrectly.
Lunar operations
On October 3, it entered an initial 101 kilometre polar lunar orbit.On October 9, the relay satellite was released into a 100 kilometre orbit, while on October 12 the VLBI satellite was released into a 100 kilometre one. Finally, by October 19, the orbiter was in a circular 100 kilometres (62.1 mi) orbit. The nominal mission duration was one year plus possible extensions.
On October 31, 2007, Kaguya deployed its Lunar Magnetometer, Lunar Radar Sounder, Earth-looking Upper Atmosphere and Plasma Imager. On December 21, 2007, Kaguya began regular operations after all fifteen observation experiments had been satisfactorily verified.
Kaguya completed the planned operation by the end of October 2008 and began extended operations planned to continue through March 2009. It would then be sent into a circular 50 kilometres (31.1 mi) orbit, and finally to a elliptical 20 kilometre one, with a controlled impact occurring by August 2009. Because of a degraded reaction wheel, the plan was changed so that on February 1, 2009, the orbit was lowered to 50 kilometres (31.1 mi) ± 20 kilometres (12.4 mi),
and impact occurred at 18:25 UTC on June 10, 2009.
Main orbiter
- Shape: octagonal prism
- Mass: 2914 kilograms (6,424.3 lb)
- Size: 2.1 x 2.1 x 4.8 m (6.9 x 6.9 x 16 ft)
- Attitude controlAttitude dynamics and controlSpacecraft flight dynamics is the science of space vehicle performance, stability, and control. It requires analysis of the six degrees of freedom of the vehicle's flight, which are similar to those of aircraft: translation in three dimensional axes; and its orientation about the vehicle's center...
: Three-axis stabilized - Power: 3.5 kW (Max.)
- Mission period: 1 year
- Mission orbit: Circular, 100 kilometres (62.1 mi)
- Inclination: 90 degrees
Okina (small relay satellite)
Okina (formerly Rstar) and Ouna (formerly Vstar) were octagonal prisms to support radio science. Okina relayedRepeater
A repeater is an electronic device that receives asignal and retransmits it at a higher level and/or higher power, or onto the other side of an obstruction, so that the signal can cover longer distances.-Description:...
radio communications between the orbiter and the Earth when the orbiter was behind the Moon. This allowed, for the first time, the direct Doppler shift measurements needed
to precisely map the gravitational field of the lunar farside; previously, the farside gravity field could only be inferred by nearside measurements. The relay satellite impacted the lunar farside near the Mineur D
Mineur (crater)
Mineur is a lunar crater that lies just to the northeast of the prominent crater Jackson on the far side of the Moon. Jackson lies at the center of a broad ray system, a portion of which covers Mineur. The closest other crater of note is Cockcroft to the north....
crater at 19:46 JST (10:46 UTC) on February 12, 2009.
- Function: two-way radio science relay, orbiter-earth
- Mass: 53 kilograms (116.8 lb)
- Size: 1.0 x 1.0 x 0.65 m (3.3 x 3.3 x 2.1 ft)
- Attitude control: spin-stabilizedSpin-stabilized satelliteA spin-stabilized satellite is a satellite which has the motion of one axis held fixed by spinning the satellite around that axis, using the gyroscopic effect.The attitude of a satellite or any rigid body is its orientation in space...
- Power: 70 W
- Initial orbit: 100 to 2400 km (62.1 to 1,491.3 )
- Inclination: 90 degrees
Ouna (VLBI satellite)
Ouna used Very Long Baseline InterferometryVery Long Baseline Interferometry
Very Long Baseline Interferometry is a type of astronomical interferometry used in radio astronomy. It allows observations of an object that are made simultaneously by many telescopes to be combined, emulating a telescope with a size equal to the maximum separation between the telescopes.Data...
as a second way to map the Moon's gravity field. It was especially useful at the lunar limb
Lunar limb
The lunar limb is the edge of the visible surface of the Moon as viewed from Earth. Libration of the Moon, with its irregular surface, leads to small changes in its profile, and this complicates the task of precisely calculating eclipse times and durations...
, where the gravitational acceleration is perpendicular to the line of sight to earth, making Doppler measurements unsuitable.
- Function: VLBI radio science
- Mass: 53 kilograms (116.8 lb)
- Size: 1.0 x 1.0 x 0.65 m (3.3 x 3.3 x 2.1 ft)
- Attitude control: spin-stabilized
- Power: 70 W
- Initial orbit: 100 to 800 km (62.1 to 497.1 )
- Inclination: 90 degrees
Payload
SELENE carried 13 scientific instruments "to obtain scientific data of the lunar origin and evolution and to develop the technology for the future lunar exploration":- Terrain camera (TC) (resolution 10 meters [33 ft] per pixel)
- X-RayX-rayX-radiation is a form of electromagnetic radiation. X-rays have a wavelength in the range of 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays and longer than gamma...
fluorescence spectrometerSpectrometerA spectrometer is an instrument used to measure properties of light over a specific portion of the electromagnetic spectrum, typically used in spectroscopic analysis to identify materials. The variable measured is most often the light's intensity but could also, for instance, be the polarization...
(XRS) - Lunar magnetometerMagnetometerA magnetometer is a measuring instrument used to measure the strength or direction of a magnetic field either produced in the laboratory or existing in nature...
(LMAG) - Spectral profiler (SP) (resolution per pixel: 562 x 400 m [1840 x 1310 ft)
- Multi-band imager (MI) (resolution of visible light 20 [66 ft] meters per pixel, near-infrared 62 meters [200 ft] per pixel)
- laser altimeterLIDARLIDAR is an optical remote sensing technology that can measure the distance to, or other properties of a target by illuminating the target with light, often using pulses from a laser...
(LALT) - Lunar radarRadarRadar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio...
sounder (LRS) - Gamma rayGamma rayGamma radiation, also known as gamma rays or hyphenated as gamma-rays and denoted as γ, is electromagnetic radiation of high frequency . Gamma rays are usually naturally produced on Earth by decay of high energy states in atomic nuclei...
spectrometer (GRS) - Charged particleCharged particleIn physics, a charged particle is a particle with an electric charge. It may be either a subatomic particle or an ion. A collection of charged particles, or even a gas containing a proportion of charged particles, is called a plasma, which is called the fourth state of matter because its...
spectrometer (CPS) - PlasmaPlasma (physics)In physics and chemistry, plasma is a state of matter similar to gas in which a certain portion of the particles are ionized. Heating a gas may ionize its molecules or atoms , thus turning it into a plasma, which contains charged particles: positive ions and negative electrons or ions...
analyzer (PACE) - Upper atmosphere and plasma imager (UPI)
- Radio wave repeater (RSAT) aboard Okina
- Radio wave source for VLBI (VRAD) aboard Okina and Ouna
Two 2.2 megapixel CCD HDTV
High-definition television
High-definition television is video that has resolution substantially higher than that of traditional television systems . HDTV has one or two million pixels per frame, roughly five times that of SD...
camera
Camera
A camera is a device that records and stores images. These images may be still photographs or moving images such as videos or movies. The term camera comes from the camera obscura , an early mechanism for projecting images...
s, one wide-angle and one telephoto, were also on board, primarily for public relations purposes.
JAXA collected names and messages that were carried on SELENE through their "Wish Upon the Moon" campaign. 412,627 names and messages were printed on a sheet measuring 280 mm x 160 mm (11 x 6.3 in) at 70 µm
Micrometre
A micrometer , is by definition 1×10-6 of a meter .In plain English, it means one-millionth of a meter . Its unit symbol in the International System of Units is μm...
(0.0003 in) per character. The sheet was installed under the photovoltaic module
Photovoltaic module
A solar panel is a packaged, connected assembly of solar cells, also known as photovoltaic cells...
s and cooling panels beneath the multi-layered insulation.
Results
Major results include:- Improved lunar global topography maps. This detailed altitude and geological data is provided to Google for free to make Google moon 3-D.
- Detailed gravity map of the far side of the MoonFar side of the MoonThe far side of the Moon is the lunar hemisphere that is permanently turned away, and is not visible from the surface of the Earth. The far hemisphere was first photographed by the Soviet Luna 3 probe in 1959, and was first directly observed by human eyes when the Apollo 8 mission orbited the Moon...
. - First optical observation of the permanently shadowed interior of the crater ShackletonShackleton (crater)Shackleton is an impact crater that lies at the south pole of the Moon. The peaks along the crater's rim are exposed to almost continual sunlight, while the interior is perpetually in shadow. The low-temperature interior of this crater functions as a cold trap that may capture and freeze volatiles...
at the lunar south pole.
Other lunar probes
SELENE was part of a renewed global interest in lunar exploration; it was "the largest lunar mission since the Apollo program". It followed Japan's first lunar probe, HagoromoHiten
The Hiten Spacecraft , given the English name Celestial Maiden and known before launch as MUSES-A , part of the MUSES Program, was built by the Institute of Space and Astronautical Science of Japan and launched on January 24, 1990...
, launched in 1990. China
People's Republic of China
China , officially the People's Republic of China , is the most populous country in the world, with over 1.3 billion citizens. Located in East Asia, the country covers approximately 9.6 million square kilometres...
launched its Chang'e 1 lunar explorer on October 24, 2007, followed by India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
's 22 October 2008 launch of Chandrayaan-1 and the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
Lunar Reconnaissance Orbiter
Lunar Reconnaissance Orbiter
The Lunar Precursor Robotic Program is a program of robotic spacecraft missions which NASA will use to prepare for future human spaceflight missions to the Moon. Two LPRP missions, the Lunar Reconnaissance Orbiter and the Lunar Crater Observation and Sensing Satellite , were launched in June 2009...
in June 2009. The United States, Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
an countries (ESA), Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...
, Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
, India and China are planning future manned lunar exploration missions or lunar outpost construction on the Moon between 2018 and 2025.
External links
Official project site, JAXA Official launch information site, JAXA- SELENE Mission Profile by NASA's Solar System Exploration SELENE overview, ISAS/JAXA Official YouTube channel, JAXA June 10th impact location NEC Corporation's Kaguya page, NEC Corporation
- -Video- JAXA Link - Video 12 Min before Impact - close surface flyover.