SELENE explained

Kaguya
Insignia:kaguya mark.jpg
Mission Type:Lunar orbiter
Operator:JAXA
Cospar Id:2007-039A
Satcat:32054
Mission Duration:1 year and 9 months (launch date to decay date)
Manufacturer:NEC Toshiba Space Systems
Launch Mass:Total:
* Main orbiter (Kaguya):
* Relay Satellite (Okina):
* VLBI Satellite (Ouna): [1]
Power:3,486 watts
Instruments:
  • X-ray Spectrometer (XRS)
  • Gamma-ray spectrometer (GRS)
  • Multi-band Imager (MI)
  • Spectral Profiler (SP)
  • Terrain Camera (TC)
  • Lunar Radar Sounder (LRS)
  • Laser Altimeter (LALT)
  • Lunar Magnetometer (LMAG)
  • Charged Particle Spectrometer (CPS)
  • Plasma energy Angle and Composition Experiment (PACE)
  • Radio Science (RS)
  • Upper-atmosphere and Plasma Imager (UPI)
  • Relay Satellite aboard Okina (RSAT)
  • VLBI Radio source aboard Okina and Ouna (VRAD)
  • High Definition Television cameras (HDTV)
Launch Date: UTC
Launch Rocket:H-IIA 2022 F13
Launch Site:Tanegashima Yoshinobu 1
Launch Contractor:Mitsubishi
Disposal Type:Deorbited (Moon impact)
Decay Date: UTC
Orbit Epoch:September 29, 2007[2]
Orbit Reference:Selenocentric
Orbit Periapsis:281km (175miles)
Orbit Apoapsis:231910km (144,100miles)
Orbit Inclination:29.9 degrees
Orbit Period:7109.28 seconds
Apsis:selene
Interplanetary:
Type:orbiter
Arrival Date:October 3, 2007
Location:[3]

SELENE (; Selenological and Engineering Explorer), better known in Japan by its nickname, was the second Japanese lunar orbiter spacecraft following the Hiten probe.[4] Produced by the Institute of Space and Astronautical Science (ISAS) and the National Space Development Agency (NASDA), the spacecraft was launched on September 14, 2007. After orbiting the Moon for a year and eight months, the main orbiter was instructed to impact on the lunar surface near the crater Gill on June 10, 2009.[5]

Nickname

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.[6] After their successful release, its sub-satellites, Rstar and Vstar, were named Okina and Ouna, also derived from characters in the tale.[7]

Mission objectives

The main scientific objectives of the mission were to:

Launch

SELENE launched on September 14, 2007, at 01:31:01 UTC on an H-IIA (Model H2A2022) carrier rocket from Tanegashima Space Center into a 281.55km (174.95miles) (perigee) / 232960km (144,760miles) (apogee) geocentric parking orbit.[8] [9] The total launch mass was .[10]

The SELENE mission was originally scheduled to launch in 2003, but rocket failures on another mission and technical difficulties delayed the launch until 2007.[11] Launch was planned for August 16, 2007, but was postponed when some electronic components were found to be installed incorrectly.[12]

Lunar operations

On October 3, it entered an initial 101kmto11741kmkm (63milesto7,296mileskm) polar lunar orbit.[13] On October 9, the relay satellite was released into a 100kmto2400kmkm (100milesto1,500mileskm) orbit, while on October 12 the VLBI satellite was released into a 100kmto800kmkm (100milesto500mileskm) one. Finally, by October 19, the orbiter was in a circular 100km (100miles) orbit.[14] 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 50km (30miles) orbit, and finally to an elliptical 20kmto100kmkm (10milesto100mileskm) one, with a controlled impact occurring by August 2009.[15] Because of a degraded reaction wheel, the plan was changed so that on February 1, 2009, the orbit was lowered to ±,[16] and impact with lunar surface occurred at 18:25 UTC on June 10, 2009.

Design

The mission featured three separate spacecraft:

Main orbiter

Three-axis stabilized

Okina (small relay satellite)

Okina (formerly Rstar) and Ouna (formerly Vstar) were octagonal prisms to support radio science. Okina relayed 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 neededto 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.

Ouna (VLBI satellite)

Ouna used Very Long Baseline Interferometry 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.

Instruments

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":[17]

Two 2.2 megapixel CCD HDTV cameras, one wide-angle and one telephoto, were also on board, primarily for public outreach.[19] The HDTV system, developed by NHK (Japan Broadcasting Corporation), produced over 1.3 TB of video and stills over 19 months.[20]

JAXA collected names and messages that were carried on SELENE through their "Wish Upon the Moon" campaign.[21] 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 modules and cooling panels beneath the multi-layered insulation.[22]

Results

Major results include:

Other lunar probes

SELENE was part of a renewed global interest in lunar exploration; it was "the largest lunar mission since the Apollo program".[27] It followed Japan's first lunar probe, Hagoromo, launched in 1990.[28] China launched its Chang'e 1 lunar explorer on October 24, 2007, followed by India's October 22, 2008 launch of Chandrayaan-1 and the United States Lunar Reconnaissance Orbiter in June 2009. The United States, European countries (ESA), Russia, Japan, India and China are planning future crewed lunar exploration missions or lunar outpost construction on the Moon between 2018 and 2025.[29]

See also

External links

Notes and References

  1. Web site: SELENE/Kaguya . NASA . December 2, 2022.
  2. Web site: Satellite Catalog . Jonathan's Space Page . Jonathan . McDowell . May 3, 2018.
  3. Web site: Result of controlled drop of lunar orbiter "KAGUYA (SELENE)". JAXA. June 9, 2024. June 9, 2024. https://web.archive.org/web/20240609054253/https://www.jaxa.jp/press/2009/06/20090611_kaguya_j.html. live.
  4. News: Kaguya – Another Chapter for the Lunar Saga . Red Orbit . September 14, 2007 . September 14, 2007 . 2011-05-22 . https://web.archive.org/web/20110522040727/http://www.redorbit.com/news/space/1066163/kaguya__another_chapter_for_the_lunar_saga/index.html . dead .
  5. Web site: KAGUYA Lunar Impact . JAXA . June 24, 2009.
  6. Web site: "KAGUYA" selected as SELENE's nickname. October 13, 2007.
  7. KAGUYA (SELENE) / Result of the Separation of the VRAD Satellite (Vstar) . October 12, 2007 . October 13, 2007 . 2012-03-20 . https://web.archive.org/web/20120320205250/http://www.jaxa.jp/press/2007/10/20071012_kaguya_e.html . dead .
  8. Web site: Kaguya Rockets Toward the Moon . September 15, 2007 . Emily Lakdawalla . September 14, 2007 . 2012-02-06 . https://web.archive.org/web/20120206131248/http://planetary.org/news/2007/0914_Kaguya_Rockets_Toward_the_Moon.html . dead .
  9. Web site: 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） . ja . September 19, 2007 . MHI / JAXA.
  10. Web site: 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) . MHI / JAXA . ja.
  11. Web site: Japan launches first lunar probe . September 14, 2007. September 14, 2007 . BBC News.
  12. Web site: Launch Postponement of the KAGUYA (SELENE). July 20, 2007. August 15, 2007.
  13. KAGUYA (SELENE) Result of the Lunar Orbit Injection Maneuver (LOI1) – Lunar orbit injection was confirmed. October 5, 2007 . October 5, 2007 . JAXA . 2012-05-14 . https://web.archive.org/web/20120514023250/http://www.jaxa.jp/press/2007/10/20071005_kaguya_e.html . dead .
  14. Web site: かぐや/H-IIA13号機 打上げ特設サイト. ja. October 1, 2007.
  15. Web site: 月周回衛星「かぐや（SELENE）」の定常運用終了と後期運用計画について . ja . November 5, 2008 . November 5, 2008.
  16. Web site: 月周回衛星「かぐや（SELENE）」の 状況について . ja . February 18, 2009 . February 22, 2009.
  17. Web site: Kaguya (SELENE) . June 25, 2007 . JAXA.
  18. Web site: LISM [TC, MI, SP] ]. June 25, 2007 . Kaguya (SELENE) . JAXA.
  19. Web site: KAGUYA (SELENE) – Mission Instruments – HDTV . March 1, 2009.
  20. Results of High-Definition Television System (HDTV) on Board SELENE (KAGUYA). 40th Lunar and Planetary Science Conference (2009). 9 December 2022.
  21. 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 . The Planetary Society . January 11, 2007 . July 14, 2007 . 2012-02-12 . https://web.archive.org/web/20120212094535/http://www.planetary.org/about/press/releases/2007/0111_Send_a_New_Years_Message_to_the_Moon.html . dead .
  22. Web site: セレーネ「月に願いを!」(SELENE "Wish Upon the Moon!") . July 14, 2007 . 2007 . JAXA . ja . dead . https://web.archive.org/web/20070404082251/http://www.isas.jaxa.jp/j/new/event/selene_camp/topics.shtml . April 4, 2007 .
  23. Lunar Global Shape and Polar Topography Derived from Kaguya-LALT Laser Altimetry . H. Araki . etal . Science . 5916 . 897–900 . February 13, 2009 . 10.1126/science.1164146 . 323 . 19213910. 2009Sci...323..897A . 2115707 .
  24. Farside Gravity Field of the Moon from Four-Way Doppler Measurements of SELENE (Kaguya) . N. Namiki . etal . Science . 5916 . 900–905 . February 13, 2009 . 10.1126/science.1168029 . 323 . 19213911. 2009Sci...323..900N . 5306227 .
  25. Lack of Exposed Ice Inside Lunar South Pole Shackleton Crater . J. Haruyama . etal . Science . 5903 . 938–939 . November 7, 2008 . 10.1126/science.1164020 . 322 . 18948501 . 2008Sci...322..938H. 20749838 . free .
  26. Kentaro . Terada . Shoichiro . Yokota . Yoshifumi . Saito . Naritoshi . Kitamura . Kazushi . Asamura . Masaki . Nishino . January 30, 2017 . Biogenic oxygen from Earth transported to the Moon by a wind of magnetospheric ions . Nature Astronomy . 1. 2. 0026. 10.1038/s41550-016-0026 . 2017NatAs...1E..26T . 85560607 .
  27. Web site: SELENE: The largest lunar mission since the Apollo program . April 21, 2008 . 2013-10-24 . https://web.archive.org/web/20131024124342/http://www.jaxa.jp/projects/sat/selene/index_e.html . dead .
  28. Web site: Hiten . . September 14, 2007.
  29. Web site: NASA Authorization Act of 2008 – Section 404 – Lunar Outpost . . October 22, 2008 . 2008-10-22 . 2016-07-04 . https://web.archive.org/web/20160704213213/http://thomas.loc.gov/cgi-bin/query/z?c110:H.R.6063: . dead .

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