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Mission typeSpace observatory
OperatorJAXA / ISAS
Mission durationProposed: 3 years
Spacecraft properties
ManufacturerInstitute of Space and Astronautical Science
Dry massApprox. 450 kg [1]
Power< 500 W [1]
Start of mission
Launch date2020s
RocketH3 rocket
DiameterLFT: 40 cm[2]
HFT: 20 cm[2]
Focal length~1,100 mm [3]
Capacity10 Gb/day [1]
Superconducting polarimeters
Large-class Missions

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 cosmic microwave background (CMB) in a form of polarization pattern called B-mode.

LiteBIRD and OKEANOS were the two finalists for Japan's second Large-Class Mission.[4][5] In May 2019, LiteBIRD was selected by the Japanese space agency.[6] LiteBIRD is planned to be launched in the 2020s with an H3 launch vehicle for three years of observations at a Sun-Earth Lagrangian point L2.[4]


Cosmological inflation is the leading theory of the first instant of the 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.[2] Inflation predicts that primordial gravitational waves were created during the inflationary era, about 10−38 second after the beginning of the universe.[7] The primordial gravitational waves are expected to be imprinted in the CMB polarization map as special patterns, called the B-mode.[7] Measurements of polarization of the CMB radiation are considered as the best probe to detect the primordial gravitational waves,[8] that could bring a profound knowledge on how the Universe began, and may open a new era of testing theoretical predictions of quantum gravity, including those by the superstring theory.[7]

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.[1][9] The design concept is being studied by an international team of scientists from Japan, U.S., Canada and Europe.[4][10]


In order to separate CMB from the Galactic emission, the measurements would cover 40 GHz to 400 GHz during a 3-year full sky survey using two telescopes on LiteBIRD.[2][4] The Low Frequency Telescope (LFT) covers 40 GHz to 235 GHz, and the High Frequency Telescope (HFT) covers 280 GHz to 400 GHz. LFT has a 400 mm aperture Crossed-Dragone telescope, and HFT has a 200 mm aperture on-axis refractor with two silicon lenses.[2][4][11] The baseline design considers an array of 2,622 superconducting polarimeter detectors.[2][11] The entire optical system would be cooled down to approximately 5 K (−268.15 °C; −450.67 °F) to minimize the thermal emission,[12] and the focal plane is cooled to 100 mK with a two-stage sub-Kelvin cooler.[2]

See also[edit]


  1. ^ a b c d 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
  2. ^ a b c d e f g The LiteBIRD Satellite Mission – Sub-Kelvin Instrument. A. Suzuki, P. Ade, Y. Akiba, etal. arXive repository. Submitted: 15 March 2018.
  3. ^ Mission design of LiteBIRD. T. Matsumura, Y Akiba, J. Borrill, etal. arXive repository. Filed: 12 November 2013.
  4. ^ a b c d e 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.
  5. ^ 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).
  6. ^ Goda, Roku (May 22, 2019). "宇宙最古の光、捉えられるか JAXA、衛星打ち上げへ". The Asahi Shimbun (in Japanese). Retrieved 2017-05-30.
  7. ^ a b c LiteBird Science. JAZA/ISAS. Accessed 6 October 2018.
  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.
  9. ^ 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.
  10. ^ LiteBIRD - Team Members. JAXA/ISAS. Accessed: 8 October 2018.
  11. ^ a b LiteBIRD instrumentation. JAXA/ISAS. Accessed: 6 October 2018.
  12. ^ 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.

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