View source for Astronomy:LiteBIRD

{{Short description|Planned Japanese small space observatory}}
{{Infobox spaceflight
| name               = ''LiteBIRD''<!--defaults to page title-->
| names_list         = <!--list of previous names if the spacecraft has been renamed. 
Include the dates applicable if possible, and separate each name with a linebreak. 
Omit if the spacecraft has only ever been known by one name. 
Do not include Harvard, COSPAR/NSSDC or SATCAT/NORAD/NASA designations as alternative names-->

<!--image of the spacecraft/mission-->| image              = <!--omit the "file" prefix-->
| image_caption      = <!--image caption-->
| image_alt          = <!--image alt text-->
| image_size         = <!--include px/em; defaults to 220px-->

<!--Basic details-->| mission_type       = Space observation
| operator           = [[Organization:JAXA|JAXA]] / [[Organization:Institute of Space and Astronautical Science|ISAS]]
| COSPAR_ID          = <!--NSSDC ID-->
| SATCAT             = <!--satellite catalogue number, omit leading zeroes-->
| website            = {{url|https://www.isas.jaxa.jp/en/missions/spacecraft/future/litebird.html}}
| mission_duration   = Planned: 3 years

<!--Spacecraft properties-->| spacecraft         = <!--Spacecraft name/serial number (eg. Space Shuttle ''Discovery'', Apollo CM-118), etc-->
| spacecraft_type    = <!--eg. GPS Block II, Kobalt-M, US-K, etc-->
| spacecraft_bus     = <!--eg. A2100M, Star-2, etc-->
| manufacturer       = [[Organization:Institute of Space and Astronautical Science|Institute of Space and Astronautical Science]] <!--company or companies who built the satellite-->
| launch_mass        = <!--fuelled mass at launch, not including rocket or upper stage-->
| BOL_mass           = <!--spacecraft mass in orbit at beginning of operational life, after LEOP phase-->
| dry_mass           = Approx. 450 kg <ref name= 'Hazumi 2012'>[https://www.spiedigitallibrary.org/conference-proceedings-of-spie/8442/844219/LiteBIRD--a-small-satellite-for-the-study-of-B/10.1117/12.926743.short?SSO=1 LiteBIRD: a small satellite for the study of B-mode polarization and inflation from cosmic background radiation detection]. M. Hazumi; J. Borrill; Y. Chinone; M. A. Dobbs; H. Fuke; A. Ghribi, aetal. ''Proceedings'' Volume 8442, Space Telescopes and Instrumentation 2012: Optical, Infrared, and Millimeter Wave; 844219 (2012). Event: SPIE Astronomical Telescopes + Instrumentation, 2012, Amsterdam, Netherlands 21 September 2012. {{doi|10.1117/12.926743}}</ref>
| payload_mass       = <!--Mass of cargo carried by spacecraft (eg. for Space Shuttle), or total mass of instrumentation/equipment/experiments for mission-->
| dimensions         = <!--body dimensions and solar array span-->
| power              = < 500 W <ref name= 'Hazumi 2012'/> <!--end-of-life power, in watts-->

<!--Launch details-->| launch_date        = 2032 (planned)<ref name="dsbt-20230703" />
| launch_rocket      = [[Engineering:H3 (rocket)|H3]]
| launch_site        = Tanegashima LA-Y2
| launch_contractor  = [[Company:Mitsubishi Heavy Industries|Mitsubishi Heavy Industries]]

<!--Telescope parameters-->| instrument_type    = <!--converts telescope fields to suit a camera or other similar instrument-->
| telescope_name     = <!--name, if different to the satellite-->
| telescope_type     = <!--type of telescope, mirror arrangement, etc-->
| telescope_diameter = LFT: 40 cm<ref name='Suzuki 2018'/><br/> HFT: 20 cm<ref name='Suzuki 2018'/>
| telescope_focal_length = ~1,100 mm <ref name='Matsumura 2013'>[https://arxiv.org/abs/1311.2847 Mission design of LiteBIRD]. T. Matsumura, Y Akiba, J. Borrill, etal. arXive repository. Filed: 12 November 2013.</ref>
| telescope_area     = <!--collecting area-->
| telescope_wavelength = <!--wavelengths at which the telescope operates-->
| telescope_resolution = <!--resolution of telescope-->
| instruments        = Superconducting [[Physics:Polarimetry#Astronomical polarimetry|polarimeters]] <!--a list of instruments on the satellite-->

<!--transponder parameters-->| trans_band         = <!--Transponder frequency bands-->
| trans_frequency    = <!--specific frequencies-->
| trans_bandwidth    = <!--bandwidth-->
| trans_capacity     = 10 Gb/day <ref name= 'Hazumi 2012'/> <!--capacity of the transponders-->
| trans_coverage     = <!--area covered-->
| trans_TWTA         = <!--TWTA output power-->
| trans_EIRP         = <!--equivalent isotropic power-->
| trans_HPBW         = <!--half-power beam width-->

<!--Only use where a spacecraft/mission is part of a clear programme of sequential missions. 
If in doubt, leave it out-->| programme          = Large-class Missions
| previous_mission   = [[Astronomy:Martian Moons Exploration|MMX]]
| next_mission       = 
}}

'''''LiteBIRD''''' ('''Lite''' ('''Light''') '''satellite for the studies of B-mode polarization and Inflation from cosmic background Radiation Detection''') is a planned small space observatory that aims to detect the footprint of the primordial gravitational wave on the [[Astronomy:Cosmic microwave background|cosmic microwave background]] (CMB) in a form of polarization pattern called [[Astronomy:Cosmic microwave background#B-modes|B-mode]].
 
''LiteBIRD'' and [[Astronomy:OKEANOS|OKEANOS]] were the two finalists for Japan's second Large-Class  Mission.<ref name='Sekimoto 2018'>[https://www.spiedigitallibrary.org/conference-proceedings-of-spie/10698/106981Y/Concept-design-of-the-LiteBIRD-satellite-for-CMB-B-mode/10.1117/12.2313432.short Concept design of the LiteBIRD satellite for CMB B-mode polarization]. Y. Sekimoto; P. Ade; K. Arnold; J. Aumont; J. Austermann, etal. Proceedings Volume 10698, Space Telescopes and Instrumentation 2018: Optical, Infrared, and Millimeter Wave; 106981Y (2018) {{doi|10.1117/12.2313432}} Event: SPIE Astronomical Telescopes + Instrumentation, 9 August 2018, Austin, Texas, United States.</ref><ref name='Iwata 2018'>[https://www.hou.usra.edu/meetings/lpsc2018/pdf/1870.pdf INVESTIGATION OF THE SOLAR SYSTEM DISK STRUCTURE DURING THE CRUISING PHASE OF THE SOLAR POWER SAIL MISSION.] (PDF). T. Iwata, T. Okada, S. Matsuura, K. Tsumura, H. Yano, T. Hirai, A. Matsuoka, R. Nomura, D. Yonetoku, T. Mihara, Y. Kebukawa, M. ito, M. Yoshikawa, J. Matsu-moto, T. Chujo, and O. Mori. 49th Lunar and Planetary Science Conference 2018 (LPI Contrib. No. 2083).</ref> In May 2019, LiteBIRD was selected by the [[Organization:JAXA|Japanese space agency]].<ref name="Asahi2019">{{cite news |last=Goda |first=Roku |date=May 22, 2019 |title=宇宙最古の光、捉えられるか ＪＡＸＡ、衛星打ち上げへ |url=https://www.asahi.com/articles/ASM5P5QS9M5PULBJ00M.html |language=ja |newspaper=The Asahi Shimbun |access-date=2017-05-30}}</ref> ''LiteBIRD'' is planned to be launched in 2032 with an [[Engineering:H3 (rocket)|H3 launch vehicle]] for three years of observations at the Sun-Earth [[Astronomy:Lagrangian point|Lagrangian point]] L2.<ref name="dsbt-20230703">{{cite web |url=https://www.d-sbt.fr/en/Pages/News/2023_Thomas-Prouve.aspx |title=The origin of the Universe will be unveiled by the LiteBIRD cryogenic satellite |work=[[Organization:Grenoble Alpes University|Grenoble Alpes University]] |date=3 July 2023 |access-date=26 December 2023}}</ref><ref name="in2p3-2019">{{cite web |last=Montier |first=L. |url=https://indico.in2p3.fr/event/19378/sessions/12141/attachments/54391/71180/20190710_LBDay_Overview.pdf |title=LiteBIRD Overview |work=IN2P3 |date=10 July 2019 |access-date=29 April 2021}}</ref>

==Overview==

[[Astronomy:Inflation (cosmology)|Cosmological inflation]] is the leading theory of the first instant of the [[Astronomy:Universe|universe]], called the Big Bang theory. Inflation postulates that the universe underwent a period of rapid expansion an instant after its formation, and it provides a convincing explanation for cosmological observations.<ref name='Suzuki 2018'>[https://arxiv.org/abs/1801.06987 The LiteBIRD Satellite Mission – Sub-Kelvin Instrument]. A. Suzuki, P. Ade, Y. Akiba, etal. arXive repository. Submitted: 15 March 2018.</ref> Inflation predicts that primordial gravitational waves were created during the inflationary era, about 10<sup>−38</sup> second after the beginning of the universe.<ref name='LiteBIRD Home'>[http://litebird.jp/eng/?page_id=2 LiteBird Science] {{Webarchive|url=https://web.archive.org/web/20200212145351/http://litebird.jp/eng/?page_id=2 |date=2020-02-12 }}. JAZA/ISAS. Accessed 6 October 2018.</ref> The primordial gravitational waves are expected to be imprinted in the CMB polarization map as special patterns, called the [[Astronomy:Cosmic microwave background#B-modes|B-mode]].<ref name='LiteBIRD Home'/> Measurements of [[Physics:Polarization (waves)|polarization]] of the CMB radiation are considered as the best probe to detect the primordial gravitational waves,<ref name='Matsumura 2016'>[https://link.springer.com/article/10.1007/s10909-016-1542-8 LiteBIRD: Mission Overview and Focal Plane Layout]. T. Matsumura, Y. Akiba, K. Arnold, J. Borrill, R. Chendra, etal. ''Journal of Low Temperature Physics''. August 2016, Volume 184, Issue 3–4, pp 824–831.</ref> that could bring a profound knowledge on how the Universe began, and may open a new era of testing theoretical predictions of [[Physics:Quantum gravity|quantum gravity]], including those by the [[Physics:Superstring theory|superstring theory]].<ref name='LiteBIRD Home'/>
 
The science goal of ''LiteBIRD'' is to measure the CMB polarization over the entire sky with the sensitivity of δr <0.001, which allows testing the major single-field slow-roll inflation models experimentally.<ref name='Hazumi 2012'/><ref name='Matsumura 2014'>[https://www.spiedigitallibrary.org/conference-proceedings-of-spie/9143/91431F/LiteBIRD-mission-overview-and-design-tradeoffs/10.1117/12.2055794.short LiteBIRD: mission overview and design tradeoffs]. T. Matsumura; Y. Akiba; J. Borrill; Y. Chinone, etal. Proceedings Volume 9143, Space Telescopes and Instrumentation 2014: Optical, Infrared, and Millimeter Wave; 91431F (2014) {{doi|10.1117/12.2055794}} Event: SPIE Astronomical Telescopes + Instrumentation, 2 August 2014, Montréal, Quebec, Canada.</ref> The design concept is being studied by an international team of scientists from Japan, U.S., Canada and Europe.<ref name='Sekimoto 2018'/><ref>[http://litebird.jp/eng/?page_id=10 LiteBIRD - Team Members] {{Webarchive|url=https://web.archive.org/web/20181007073758/http://litebird.jp/eng/?page_id=10 |date=2018-10-07 }}. JAXA/ISAS. Accessed: 8 October 2018.</ref>

==Telescopes==

In order to separate CMB from the galactic emission, the measurements will cover 40&nbsp;GHz to 400&nbsp;GHz during a 3-year full sky survey using two telescopes on ''LiteBIRD''.<ref name='Suzuki 2018'/><ref name='Sekimoto 2018'/> The Low Frequency Telescope (LFT) covers 40&nbsp;GHz to 235&nbsp;GHz, and the High Frequency Telescope (HFT) covers 280&nbsp;GHz to 400&nbsp;GHz. LFT has a 400&nbsp;mm aperture
Crossed-Dragone telescope, and HFT has a 200&nbsp;mm aperture on-axis refractor with two silicon lenses.<ref name='Suzuki 2018'/><ref name='Sekimoto 2018'/><ref name=Instrumentation/> The baseline design considers an array of 2,622 superconducting [[Physics:Polarimeter|polarimetric]] detectors.<ref name='Suzuki 2018'/><ref name=Instrumentation>[http://litebird.jp/eng/?page_id=8 LiteBIRD instrumentation] {{Webarchive|url=https://web.archive.org/web/20181007073743/http://litebird.jp/eng/?page_id=8 |date=2018-10-07 }}. JAXA/ISAS. Accessed: 6 October 2018.</ref> The entire optical system will be cooled down to approximately {{convert|5|K|C F}} to minimize the thermal emission,<ref name='Sugai 2016'>[https://www.spiedigitallibrary.org/conference-proceedings-of-spie/9904/99044H/Optical-designing-of-LiteBIRD/10.1117/12.2232008.short Optical designing of LiteBIRD]. Hajime Sugai; Shingo Kashima; Kimihiro Kimura; Tomotake Matsumura; Masanori Inoue; Makoto Ito; Toshiyuki Nishibori; Yutaro Sekimoto; Hirokazu Ishino; Yuki Sakurai; Hiroaki Imada; Takenori Fujii. Proceedings Volume 9904, Space Telescopes and Instrumentation 2016: Optical, Infrared, and Millimeter Wave; 99044H (2016) {{doi|10.1117/12.2232008}} Event: SPIE Astronomical Telescopes + Instrumentation, 2016, Edinburgh, United Kingdom. 29 July 2016.</ref> and the focal plane is cooled to 100 mK with a two-stage sub-Kelvin cooler.<ref name='Suzuki 2018'/>

==See also==
*[[Astronomy:POLARBEAR|POLARBEAR]]
*[[Physics:BICEP and Keck Array|BICEP and Keck Array]]

==References==
{{reflist}}

==External links==
*[http://litebird.jp/eng/ LiteBIRD Official home page] {{Webarchive|url=https://web.archive.org/web/20201111162731/http://litebird.jp/eng/ |date=2020-11-11 }}
*[https://www.isas.jaxa.jp/en/missions/spacecraft/future/litebird.html ISAS/JAXA LiteBIRD page]
*[https://pcos.gsfc.nasa.gov/physpag/presentations/physpag-meeting4/Hazumi_IPSAG_WedPM.pdf LiteBird System Overview] from 2012

{{Space observatories}}
{{CMB experiments}}
{{Future spaceflights}}

{{DEFAULTSORT:LiteBIRD}}
[[Category:Proposed spacecraft]]
[[Category:Space telescopes]]
[[Category:Physical cosmology]]
[[Category:Cosmic microwave background experiments]]

{{Sourceattribution|LiteBIRD}}