Chinese Deep Space Network

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Chinese Deep Space Network is located in China
Kashi
Kashi
Jiamusi
Jiamusi
Kunming
Kunming
Ürümqi
Ürümqi
Miyun
Miyun
FAST
FAST
Qitai
Qitai
21CMA
21CMA
CSRH
CSRH
Tian Ma
Tian Ma
Sheshan
Sheshan
Chinese Deep Space Network and radioastronomy facilities in China   in use ·   planned ·   radioastronomy facility

The Chinese Deep Space Network (CDSN) is a network of large antennas and communication facilities that are used for the interplanetary spacecraft missions of China. It is managed by the China Satellite Launch and Tracking Control General (CLTC).[1][2] They also deal with radio-astronomical and radar observations.

The network was first needed for the lunar mission Chang'e 1,[3][4]and since has been used to support future missions to the Moon and Mars such as Chang'e 5, and Tianwen-1 missions. Similar deep space networks are run by the United States, Russia, European countries, Japan, and India.

Introduction[edit]

Nanshan 25-meter radio telescope at Xinjiang Astronomical Observatory (XAO), Chinese Academy of Sciences.

In principle, a Chinese deep space network has existed since 1993 with the commissioning of the Nanshan 25-meter telescope in the mountains south of Ürümqi. The 25-meter antenna of the Shanghai Astronomical Observatory was then not only able to participate in the Southern Hemisphere VLBI Experiment program, but also to form its own Chinese baseline together with Ürümqi and observe and measure distant objects.

All stations are equipped with high-precision hydrogen maser clocks and connected via powerful communication networks. All stations comply with the provisions of the Consultative Committee for Space Data Systems (CCSDS), so data exchange with the systems of other space agencies is possible despite different technical equipment.

The antennas of Sheshan, Ürümqi, Miyun, Kunming and Tianma can be interconnected to form a national association and in this way form the Chinese VLBI Network (CVN), a VLBI telescope the size of China. The evaluation of the data from the CVN takes place in the VLBI observation base Sheshan of the Shanghai Astronomical Observatory. The facilities in Shanghai and Ürümqi are also integrated into the European VLBI Network (EVN).

Network[edit]

Tianma 65-meter radio telescope at Shanghai Astronomical Observatory (SHAO), Chinese Academy of Sciences.

In 2007, the network consisted of:

  • Ground control stations in Kashgar and Qingdao (in the Shandong province).
  • 18-meter antennas in Qingdao and Kashgar
  • A 50-meter antenna at Miyun (~116°E), near Beijing.
  • A 40-meter antenna in Yunnan (~101°E).

In 2012, improvements were made to support Chang'e 3 and Chang'e 4 Moon missions, including:[5]

  • Upgrades to the ground facilities at Kashgar and Qingdao, and a deep-space ground control station at Jiamusi.
  • A new 35-meter antenna at the Kashgar station.
  • A 64-meter antenna in Jiamusi. (~130°E)
The Neuquén ground station of the Chinese Deep Space Network.

In 2014, China and Argentina signed an agreement allowing China to construct the Espacio Lejano Station in South America.[6] The station was built in Neuquén Province, Argentina (~70°W), with a 50 million-dollar investment. The facility, a part of Chinese Lunar Exploration Program,[7][8] was inaugurated in October 2017.[9] The station is seen by some as a symbol of China's increased role in South America's politics and economy.[10]

Since 2018, China Satellite Launch and Tracking Control General (CLTC) was a customer of the Swedish Space Corporation (SSC), which provided CLTC services, including TT&C for pre-defined civilian satellites within research, Earth observation and weather data as well as for other scientific spacecraft.[11] It was reported by Reuters on 21 September 2020 that SSC decided not to renew its contracts with China to help operate Chinese satellites from SSC's ground stations, or seek new business with China.[12]

In late 2020, the Kashgar ground station was upgraded from one single 35-meter antenna to an antenna array consisting of four 35-meter antennas. The capacity of the new system was equivalent to a 66-meter antenna.[13]

Systems for radio astronomy[edit]

Five-hundred-meter Aperture Spherical Telescope (FAST) as seen from above in 2020.
Primeval Structure Telescope (PaST), also called 21 Centimeter Array (21CMA).

Radio astronomy, despite using similar large antennas, is a very different field than spacecraft communication. There is no need to transmit, and the receiving bands are chosen for scientific interest.

  • The 15-meter radio telescope in Miyun was built in 1992 and used to study pulsars, but was dismantled around 2002 in favor of the 50-meter radio telescope.[14]
  • The Miyun Synthesis Radio Telescope (MSRT) is a telescope for observing solar activity and examines the frequency range of 232 MHz. It consists of 28 antennas with a diameter of 9 meters each with baselines between 18 m and 1164 m at intervals of 6 m and has been in operation since 1998.[15]
  • The Five-hundred-meter Aperture Spherical Telescope (FAST) is the radio telescope with the world's largest primary mirror. The total diameter of the immovable spherical main mirror is 500 meters; signals can be effectively received over an area with a diameter of 300 meters (aperture). FAST is mainly used for radio astronomy. However, FAST will play an important role in the China's 2020 Mars mission, because of the frequency range of its receivers (70 MHz to 3 GHz). Any Mars landing, such as will be attempted by Tianwen-1, must decelerate from many times the speed of sound to 0 within 6–8 minutes,[16] so the frequency of the carrier wave of the telemetry signals in the X-band changes rapidly due to the Doppler effect. In the event of the sudden braking caused by opening the parachute, the regular deep-space stations will most likely lose contact with the probe. For backup, Mars landings therefore enlist the cooperation of radio astronomy facilities that can receive decimeter band (UHF) communication.[17][18][19][20]
  • Primeval Structure Telescope (PaST), also called 21 Centimetre Array (21CMA), in Ulastai, Xinjiang was completed in 2006. It was expanded in 2009 with new, low-noise amplifiers and better computer technology for evaluation. This remote valley array studies the low level emissions of neutral hydrogen from the hydrogen line.[21] The array consists of 81 groups (pods) with a total of 10287 antennas. These are arranged in two mutually perpendicular arms, one 6.1 km long in an east-west direction, the other 4 km long in a north-south direction. Each antenna has 16 dipoles with lengths between 0.242 and 0.829 meters and covers a frequency range from 50 to 200 MHz.[22]

Planned or under construction stations[edit]

  • The Qitai Radio Telescope (QTT) is a planned 110-meter radio telescope to be built in Qitai County in Xinjiang, China. Upon completion, which is scheduled for 2023,[23] it will be the world's largest fully steerable single-dish radio telescope. It is intended to operate at 300 MHz to 117 GHz. The fully steerable dish of the QTT will allow it to observe 75% of the stars in the sky at any given time.[24] The QTT and the FAST, also located in China, can both observe frequencies in the "water hole" that has traditionally been favored by scientists engaged in the search for extraterrestrial intelligence (SETI), meaning that each observatory could provide follow-up observations of putative signals from extraterrestrials detected in this quiet part of the radio spectrum at the other observatory.[25]

Relay satellites[edit]

China has several relay satellites of the Tianlian series (currently consisting of the Tianlian I and Tianlian II series) in geostationary orbits, which can relay data to each other and to the ground, thus enabling communication with spacecraft that have no direct contact with ground stations. The technology of the relay satellites enables intermediate storage of data, a higher bandwidth of data connections, and greater sky coverage. These satellites were originally placed in orbit as of 2008 for communication with the Shenzhou spacecraft of the manned space program. But they are also used for deep-space missions, for example in 2020 for the Mars mission Tianwen-1, where the satellites Tianlian 1B and Tianlian 2A were parked for orbit tracking and the transmission of telemetry data from the probe.[26]

Moon missions[edit]

Main article: Chinese Lunar Exploration Program

Planetary missions[edit]

Main article: Planetary Exploration of China

See also[edit]

References[edit]

  1. ^ "China Satellite Launch and Tracking Control General (CLTC)". Nuclear Threat Initiative. 31 January 2013. Retrieved 23 June 2021.
  2. ^ Dinatale, Martín (8 September 2014). "Preocupa el eventual uso militar de un área espacial de China en el Sur". La Nación (in Spanish). Retrieved 23 June 2021.
  3. ^ Xie, Renjiang (14 February 2007). "Gearing up for Chang'e". Astronomy. Retrieved 23 June 2021.
  4. ^ Yan, Jianguo; Ping, Jing-Song; Li, Fei (2008). Precise orbit determination of Smart-1 and Chang'E-1. 37th COSPAR Scientific Assembly. Bibcode:2008cosp...37.1381J.
  5. ^ "China Builds Deep Space Network" (PDF). China Science and Technology Newsletter. No. 606. 10 January 2011. Archived from the original (PDF) on 27 September 2011. Retrieved 21 June 2011.
  6. ^ Watson-Lynn, Erin (9 June 2020). "The gravity of China's space base in Argentina". The Interpreter. Lowy Institute. Retrieved 23 June 2021.
  7. ^ "Chinese space station is "for exclusively scientific and civilian purposes": Argentine gov't". Xinhua News Agency. 30 June 2015. Archived from the original on 2 July 2015.
  8. ^ Lee, Victor Robert (24 May 2016). "China Builds Space-Monitoring Base in the Americas". The Diplomat. Retrieved 23 June 2021.
  9. ^ Dinatale, Martín (28 January 2018). "Tras la polémica por su eventual uso militar, la estación espacial de China en Neuquén ya empezó a funcionar". Infobae (in Spanish). Retrieved 2 June 2018.
  10. ^ Londoño, Ernesto (28 July 2018). "From a Space Station in Argentina, China Expands Its Reach in Latin America". The New York Times. Retrieved 23 June 2021.
  11. ^ "Appendix for SSC's Chinese customers" (PDF). Swedish Space Corporation. Archived from the original (PDF) on 18 June 2020. Retrieved 21 September 2020.
  12. ^ Ahlander, Johan; Barrett, Jonathan (21 September 2020). "Swedish space agency halts new business helping China operate satellites". Reuters. Archived from the original on 21 September 2020. Retrieved 21 September 2020.
  13. ^ Li, Guoli; Lü, Binghong (18 November 2020). "我国首个深空天线组阵系统正式启用" (in Chinese). Xinhua News Agency. Retrieved 29 May 2021.
  14. ^ Jin, C.; Cao, Y.; Chen, H.; Gao, J.; Gao, L.; Kong, D.; Su, Y.; Wang, M. (2006). "The Miyun 50 m Pulsar Radio Telescope". Chinese Journal of Astronomy and Astrophysics. 6: 320. doi:10.1088/1009-9271/6/S2/59. S2CID 120782642.
  15. ^ Zhang, X.Z.; Piao, T.Y.; Kang, L.S.; Pang, L. (2002). Pramesh Rao, A.; Suiarup, G.; Gopal-Krishna (eds.). "Solar Observation with Miyun Radio Telescope". The Universe at Low Radio Frequencies IAU Symposium. 199: 430–431. Bibcode:2002IAUS..199..430Z. doi:10.1017/S0074180900169517.
  16. ^ 2020中国火星探测计划（根据叶院士报告整理）. spaceflightfans.cn (in Chinese). 14 March 2018. Retrieved 23 June 2021.
  17. ^ Sarkissian, John (6 August 2012). "The Parkes MSL EDL Track". CSIRO Parkes Observatory. Retrieved 23 June 2021.
  18. ^ Esterhuizen, S.; Asmar, S. W.; De, K.; Gupta, Y.; Katore, S. N.; Ajithkumar, B. (March 2019). "ExoMars Schiaparelli direct-to-earth observation using GMRT". Radio Science. 54 (3): 314–325. doi:10.1029/2018RS006707.
  19. ^ Dong, Guangliang; Li, Haitao; Hao, Wanhong; Wang, Hong; Zhu, Zhiyong; Shi, Shanbin; Fan, Min; Zhou, Huan; Xu, Dezhen (April 2018). "中国深空测控系统建设与技术发展" [Development and Future of China's Deep Space TT&C System]. Journal of Deep Space Exploration (in Chinese). 5 (2): 99–114. doi:10.15982/j.issn.2095-7777.2018.02.001.
  20. ^ Morabito, David D.; Schratz, Brian; Bruvold, Kris; Ilott, Peter; Edquist, Karl; Cianciolo, Alicia Dwyer (15 May 2014). "The Mars Science Laboratory EDL Communications Brownout and Blackout at UHF" (PDF). The Interplanetary Network Progress Report. 42–197: 1–22. Bibcode:2014IPNPR.197A...1M.
  21. ^ "The 21 CentiMeter Array (21CMA)". National Astronomical Observatories, Chinese Academy of Sciences. Retrieved 23 June 2021.
  22. ^ Zheng, Qian; Wu, Xiang-Ping; Johnston-Hollitt, Melanie; Gu, Jun-Hua; Xu, Haiguang (1 December 2016). "Radio Sources in the NCP Region Observed with the 21 Centimeter Array". The Astrophysical Journal. 832 (2): 190. arXiv:1602.06624v3. doi:10.3847/0004-637X/832/2/190.
  23. ^ O'Callaghan, Jonathan (17 January 2018). "China To Build The World's Largest Steerable Radio Telescope By 2023". IFLScience. Retrieved 11 February 2018.
  24. ^ Atkinson, Nancy (24 January 2018). "China Plans to Build the World's Largest Steerable Radio Telescope". Seeker. Retrieved 11 February 2018.
  25. ^ Mack, Eric (17 January 2018). "New biggest radio telescope to help detect alien signals". CNET. Retrieved 23 June 2021.
  26. ^ Li, Guoli; Wang, Ran (21 July 2020). "我国天基测控系统团队完成多项技术状态准备静待天问一号发射" (in Chinese). Xinhua News Agency. Retrieved 23 June 2021.
  27. ^ "Chang'e-1 – new mission to Moon lifts off". European Space Agency. 24 October 2007. Retrieved 24 October 2007.
  28. ^ "China's second moon orbiter Chang'e-2 sends data from 1.7 mln km away". Xinhua News Agency. 21 September 2011. Archived from the original on 26 September 2011. Retrieved 23 June 2021.
  29. ^ Gray, Bill (25 August 2012). "Chang'e 2: The Full Story". The Planetary Society. Archived from the original on 26 August 2012.
  30. ^ Jones, Andrew (23 July 2020). "Tianwen-1 launches for Mars, marking dawn of Chinese interplanetary exploration". SpaceNews. Retrieved 23 July 2020.
  31. ^ Roulette, Joey (5 February 2021). "Three countries are due to reach Mars in the next two weeks". The Verge. Retrieved 7 February 2021.

External links[edit]

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