Taiji Program in Space

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The Taiji Program in Space, or Taiji, is a proposed Chinese satellite-based gravitational-wave observatory. [1] [2] It is scheduled for launch in 2033 [3] to study ripples in spacetime caused by gravitational waves. The program consists of a triangle of three spacecraft orbiting the Sun linked by laser interferometers.

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There are two alternative plans for Taiji. One is to take a 20 percent share of the European Space Agency's LISA project; the other is to launch China's own satellites by 2033 to authenticate the ASE project. [4] Like LISA, the Taiji spacecraft would be 3 million kilometers apart, making them sensitive to as similar range of frequencies, [5] [6] although Taiji would perform better in some of that range. [7]

Program Goal

'Taiji Program' is the ELISA Program proposed by ESA, and the predecessor of the ELISA Program is the LISA Program cooperated by ESA and NASA. Similar to the configuration of the three networking satellites in the LISA Program, the three satellites in the Taiji Program also rotate around their centroid. The centroid also revolves in orbit around the Sun. The difference is that the phases of the LISA system, Earth system and Taiji system are different. With the Earth as the reference, the phase of the LISA system is 20 degrees behind that of the Programet, and the phase of the Taiji system is 20 degrees ahead of that of the Earth. [8] In addition, the Tai Chi Program is part of the proposed space-based gravitational wave observatories Program, the other parts of which are the Chinese Academy of Sciences (CAS) Tianqin Program and the European Space Agency (ESA) Laser Interferometer Space Antenna (LISA) and the Decimal Hertz Interferometer Gravitational-Wave Observatory (DECIGO) led by the Japan Aerospace Exploration Agency (JAXA). [9] In December 2021, a study pointed out that the gravitational wave detection network combined with Taiji and LISA will accurately measure the Hubble constant greater than 95.5% within ten years. [10] Moreover, The LISA-Taiji network has the potential to detect more than twenty stellar binary black holes (sBBHs), for which the error in luminous distance measurement is in the range of 0.05−0.2, and the relative error in sky positioning is in the range of 1−100deg2 In the range. [11]

The main scientific goal of the Taiji Program is to measure the mass, spin and distribution of black holes through the precise measurement of gravitational waves, to explore how intermediate-mass seed black holes develop if dark matter can produce black seed holes, and how enormous and supermassive black holes grow from black seed holes; Look for traces of the earliest generation of stars' genesis, development, and death, give direct restrictions on the intensity of primordial gravitational waves, and detect the polarization of gravitational waves, providing direct observational data for revealing the nature of gravity. [12] Gravitational waves can provide a clear picture of the universe because they are weakly linked to matter, and the information provided can be used in conjunction with information from telescopes and particle detectors. [13] The precise measurement of gravitational waves allows for in-depth and thorough investigation of the universe's large-scale structure, the birth and development of galaxies, and other topics; Better develop and establish a quantum theory of gravity beyond Einstein's general theory of relativity, reveal the nature of gravity, and help understand dark matter, the nature of energy, the formation of black holes, and cosmic inflation, [14] Gravitational waves can transmit information that electromagnetic waves cannot. [15] At the same time, the forward-looking technology developed from this is of great significance for improving the technical level of space science and deep space exploration; It will also play a positive role in applications such as inertial navigation, Earth science, global environmental change, and high-precision satellite platform construction. [16]

Program history

In 2008, the Chinese Academy of Sciences began demonstrating the feasibility of space gravitational wave detection, proposing the "Taiji Program" for China's space gravitational wave detection, and establishing the "single satellite, dual satellite, three satellites" and "three steps" development strategy and road map； and in August 2018, the "Taiji Program" single-satellite program was implemented in the Space Science (Phase II) Strategic Pilot Science and Technology Special Neutral Program and the first step in the three-step process was launched, that is, the Taiji-1 satellite. [17]

On August 31, 2019, Taiji-1 satellite was launched from the Jiuquan Satellite Launch Center. [18] In July 2021, "Taiji-1" has completed all the preset experimental tasks and achieved the highest precision space laser interferometry in China. It has achieved the first full performance verification of the two types of micro-push technology of Microbull-level radiofrequency ion and Hall, and took the lead in realizing the breakthrough of two non-drug control technologies in China. [19]

The optical metrology system and the non-resistance control system, both of which are part of Taiji-2 satellites, were confirmed by the Taiji-1 satellite mission; The mission's success also gave sufficient backing for the creation of Taiji-2 satellite; However, because Taiji-1 satellite only has one satellite, there is no way to test the inter-satellite laser link; The relevant unit expects to launch two satellites (Taiji-2) in 2023-2025 to clear obstacles for Taiji-3 satellites. [20] And it is expected to launch an equilateral triangle gravitational wave detection star group composed of three satellites around 2030. [21]

Program responsibility unit

The scientific application unit and user of Taiji-1 in this Program is UCAS. The Taiji Program and the ground support system are managed by China's National Space Science Center, while the satellite system is developed by the Chinese Academy of Sciences' Institute of Microsatellite Innovation; the Institute of Precision Measurement Science and Technology Innovation, Chinese Academy of Sciences, Institute of Mechanics, Chinese Academy of Sciences, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Changchun Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Singapore University of Science and Technology, Singapore Nanyang Technological University, and the Institute of Precision Measurement Science and Technology Innovation, Chinese Academy of Sciences are among the cooperative units involved in payload development. [22] In addition, the Chinese Academy of Sciences established the gravitational wave cosmic polar laboratory in Hangzhou in April 2021. [23]

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References

  1. ↑ Zhang, Yuan-Zhong; Cai, Rong-Gen; Guo, Zong-Kuan; Ruan, Wen-Hong (2018-07-25). "Taiji Program: Gravitational-Wave Sources". arXiv: 1807.09495v2 [gr-qc].
  2. ↑ China plans gravitational wave project by CHENG YINGQI, in "China Daily" (2016)
  3. ↑ Chinese gravitational-wave hunt hits crunch time - The pressure is on to choose between several proposals for space-based detectors. by David Cyranoski in "Nature" 531, 150–151 doi:10.1038/531150a (2016)
  4. ↑ China Proposes Gravitational Wave Research Projects in "TECH & MILITARY BREAKING NEWS" (2016)
  5. ↑ China plans project on gravitational wave Archived March 11, 2016, at the Wayback Machine by Cheng Yingqi, in "China Watch" (2016)
  6. ↑ "China unveils plans for two new gravitational-wave missions". Physics World. 2018-07-11. Retrieved 2019-09-20.
  7. ↑ Wu, Yue-Liang; Hu, Wen-Rui (2017-09-01). "The Taiji Program in Space for gravitational wave physics and the nature of gravity". National Science Review. 4 (5): 685–686. doi: 10.1093/nsr/nwx116 . ISSN   2095-5138.
  8. ↑ 高; 刘; 罗; 靳 (2019). "太极计划激光指向调控方案介绍". 中国光学. 12 (3): 7. doi:10.3788/CO.20191203.0425. S2CID   208090926.
  9. ↑ Yungui Gong, Jun Luo & Bin Wang (15 September 2021). "Concepts and status of Chinese space gravitational wave detection projects". Nature Astronomy. 5 (9): 881–889. arXiv: 2109.07442 . Bibcode:2021NatAs...5..881G. doi:10.1038/s41550-021-01480-3. S2CID   237513499 . Retrieved 2022-03-15.
  10. ↑ The Taiji Scientific Collaboration (24 February 2021). "China's first step towards probing the expanding universe and the nature of gravity using a space borne gravitational wave antenna". Communications Physics. 4 (1): 34. Bibcode:2021CmPhy...4...34T. doi: 10.1038/s42005-021-00529-z . S2CID   257115954.
  11. ↑ Ju Chen (陈举)1,2, Chang-Shuo Yan (闫昌硕)1,2, You-Jun Lu (陆由俊)1,2, Yue-Tong Zhao (赵悦同)1,2 and Jun-Qiang Ge (葛均强)1 (December 2021). "On detecting stellar binary black holes via the LISA-Taiji network". Research in Astronomy and Astrophysics. 21 (11): 285. arXiv: 2201.12516 . Bibcode:2021RAA....21..285C. doi:10.1088/1674-4527/21/11/285. S2CID   245574764 . Retrieved 2022-03-15.{{cite journal}}: CS1 maint: multiple names: authors list (link) CS1 maint: numeric names: authors list (link)
  12. ↑ Wen-Hong Ruan, Zong-Kuan Guo, Rong-Gen Cai and Yuan-Zhong Zhang (June 20, 2020). "Taiji program: Gravitational-wave sources". International Journal of Modern Physics A. 35 (17). arXiv: 1807.09495 . Bibcode:2020IJMPA..3550075R. doi:10.1142/S0217751X2050075X. S2CID   119488616 . Retrieved 2022-03-15.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  13. ↑ Vitor Cardoso & Paolo Pani (5 September 2017). "Tests for the existence of black holes through gravitational wave echoes". Nature Astronomy. 1 (9): 586–591. arXiv: 1707.03021 . Bibcode:2017NatAs...1..586C. doi:10.1038/s41550-017-0225-y. S2CID   256726079 . Retrieved 2022-03-15.
  14. ↑ "【科技日报】太极计划：去太空捕捉时空涟漪". China Academy of Science.
  15. ↑ Yichen Tian (November 1, 2021). "Research on the analytical development and progress of gravitational wave detection technology". Journal of Physics: Conference Series. 2083 (2): 022043. Bibcode:2021JPhCS2083b2043T. doi: 10.1088/1742-6596/2083/2/022043 . S2CID   244838691.
  16. ↑ Wen-Hong Ruan, Chang Liu, Zong-Kuan Guo, Yue-Liang Wu & Rong-Gen Cai (3 February 2020). "The LISA–Taiji network". Nature Astronomy. 4 (2): 108–109. arXiv: 2002.03603 . Bibcode:2020NatAs...4..108R. doi:10.1038/s41550-019-1008-4. S2CID   256713218 . Retrieved 2022-03-15.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  17. ↑ 科技日报 (September 24, 2019). ""太极一号"：我国空间引力波探测迈出第一步". China National Space Administration. Retrieved 2022-03-15.
  18. ↑ Xinhua News (October 29, 2019). "China plans more space science satellites". The State Council The People Republic's of China. Retrieved 2022-03-15.
  19. ↑ Wu, Yue-Liang; Luo, Zi-Ren; Wang, Jian-Yu; Bai, Meng; Bian, Wei; Cai, Rong-Gen; Cai, Zhi-Ming; Cao, Jin; Chen, Di-Jun; Chen, Ling; Chen, Li-Sheng (2021-02-24). "China's first step towards probing the expanding universe and the nature of gravity using a space borne gravitational wave antenna". Communications Physics. 4 (1): 34. Bibcode:2021CmPhy...4...34T. doi: 10.1038/s42005-021-00529-z . ISSN   2399-3650. S2CID   232042193.
  20. ↑ The Taiji Scientific Collaboration (April 3, 2021). "The pilot of Taiji program — From the ground to Taiji-2". International Journal of Modern Physics A. 36 (11n12). Bibcode:2021IJMPA..3602001T. doi:10.1142/S0217751X21020012. S2CID   240970299 . Retrieved 2022-03-15.
  21. ↑ Ziren Luo, Yan Wang, Yueliang Wu, Wenrui Hu, Gang Jin (5 May 2021). "The Taiji program: A concise overview". Progress of Theoretical and Experimental Physics. 05A108 (5). doi: 10.1093/ptep/ptaa083 .{{cite journal}}: CS1 maint: multiple names: authors list (link)
  22. ↑ "Taiji-1 Satellite Released the Scientific Achievements of the First Stage". ICTP-AP. Retrieved 2022-03-15.
  23. ↑ "【中国新闻网】引力波宇宙太极实验室落户杭州 为太极计划提供技术支撑----中国科学院". www.cas.cn. Retrieved 2022-03-15.
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