Chinese deep space network

The Chinese Deep Space Network , CDSN for short, ( 中國 深 空 網  /  中国 深 空 网 , Zhōngguó Shēnkōng Wǎng  - "Chinese Deep Space Network ") is a conglomerate of parabolic antennas that are used for communication with space probes as well as for radio astronomy and in various networks are interconnectable. In the People's Republic of China, “Deep Space” or 深 空 is defined as anything that is beyond 80,000 km, i.e. beyond the maximum orbit of the communication and reconnaissance satellites supervised by the Xi'an satellite control center. The best-known use is in the Chinese moon missions .

Kashi Giyamusi Kunming Urumqi Miyun NEARLY Qitai 21CMA CSRH Tian Ma Sheshan

Stations of the Chinese deep space network in China (red = stations of the CVN; green = militarily administered; blue = planned or under construction, black = radio astronomical station)

Tian Ma Sheshan

Stations in Shanghai. With this scale, both stations appear on one point

description

The expression "Deep Space Network" or 深 空 网 comes from the vocabulary of the People's Liberation Army and appears as an autochthonous term (not just as a translation of the American " Deep Space Network ") for the first time in 2009 during the discussion about the construction of our own deep space stations , which at the time was led under the responsibility of the Chinese lunar program. In principle, a Chinese deep space network has existed since 1993 with the commissioning of the 25 m telescope in the mountains south of Ürümqi . The 25 m 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 CCSDS , so data exchange with the systems of other space agencies is possible despite different technical equipment.

Since about the year 2000, China's space travel and radio astronomy have been booming and much has been invested. With the mission to the asteroid belt planned for 2022 , the orbit of a Jupiter moon and the flyby of Uranus , the Chinese deep space network still faces major challenges. The funding of its gradual expansion from funds from the funding program for new technologies (科技 创新 2030— 重大 项目) of the Ministry of Science and Technology is secured until 2030. This is not only about long-term goals such as titanium mining on the moon , but also about direct economic development. A position paper from 2009 explicitly states that the latest technology must be used in the construction of the Kashgar and Giyamusi deep-space stations in order to promote the development of the domestic electronics and IT industry (在 系统 设计 理念 和 技术 指标 上 国际 先进， 促进 国内 电子 信息 技术 发展).

Radio astronomical stations

Some of the antennas are used both for radio astronomy and to support space missions. These dual-use antennas are operated by institutes of the Chinese Academy of Sciences (CAS). At the time of supporting space missions, they are subordinate to the Center for Lunar Exploration and Space Projects of the National Space Agency , and there, for example, in the lunar program of the lunar exploration project leadership group (月球 探测 工程 领导 小组). The stations of the astronomical institutes only have receivers, but not their own transmitters.

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 or 中国 VLBI 网, Pinyin Zhōngguó VLBI Wǎng ), a VLBI telescope the size of China . The evaluation of the data of the CVN takes place in the VLBI observation base Sheshan (佘山 VLBI 观测 基地, Pinyin Shéshān VLBI Guāncè Jīdì ) of the Shanghai Astronomical Observatory . The facilities in Shanghai and Ürümqi are also integrated into the European VLBI Network . The Shanghai Astronomical Observatory acts in its capacity as operator of the VLBI observation base Sheshan as the spokesman for the civil radio observatories.

Military managed stations

The antennas, which are mainly used for space travel, are subordinate to the Xi'an satellite control center of the People's Liberation Army. In contrast to the stations of the astronomical institutes, the stations of the People's Liberation Army have both transmitters and receivers. The first two stations were built in Kashgar and Giyamusi and are primarily designed for the needs of space travel and from Chang'e-3 took over the tracking and control of the lunar probes. Both stations have Delta DOR for precise positioning of spacecraft and meet the standards of the Consultative Committee for Space Data Systems , so they can exchange data with other space agencies via defined interfaces. The Zapala station in Argentina is also under military control. The locations are chosen as far apart as possible, because a longer baseline enables a more precise position determination.

CVN stations until 2006

25-meter antenna from Ürümqi Nanshan

The Chinese VLBI Network (CVN or 中国 VLBI 网, Pinyin Zhōngguó VLBI Wǎng ) began with the two 25-meter radio telescopes in Sheshan and Ürümqi, which were built in the 1980s and 1990s. Four stations were used for the Chang'e-1 lunar mission (2007 to 2009). In the case of Kunming and Miyun, these were planned and financed jointly by the National Astronomical Observatories of the Chinese Academy of Sciences and the Lunar Program of the People's Republic of China - by the 39th and 54th Research Institute of the China Electronics Technology Group, which were then under the control of the People's Liberation Army Corporation built specifically for this mission and commissioned shortly beforehand. For the mission, ESA also needed support with the ESTRACK antenna network from the start phase to swinging into lunar orbit.

• 25 meters Sheshan (SH25) near Shanghai built in 1986 and operated by the Shanghai Astronomical Observatory . The station is only a few kilometers away from the new 65-meter Tianma radio telescope and can be operated together with it like a single telescope with better performance. The station in the Cassegrain beam waveguide design has six receivers with the frequency ranges 1.3, 3.6 / 13, 5, 6 and 18 cm and has been part of the European VLBI Network (EVN) since 1993 . 31 ° 5 ′ 57 "  N , 121 ° 11 ′ 58"  E

• 25 meters Nanshan near Ürümqi (UR25) has been in operation since 1993 and is operated by the Xinjiang Astronomical Observatory (XAO). It takes part in the European VLBI Network. In 2002 the system received a new receiver cooled to −253 ° C from the Australia Telescope National Facility of the Commonwealth Scientific and Industrial Research Organization . 43 ° 28 '16 "  N , 87 ° 10' 22.4"  E

• 50 meters Miyun (MRT50) near Beijing , commissioned in 2005. The system was implemented as a low-cost project, is primarily used for long-term observation of pulsars , is supposed to be able to detect gravitational waves and takes part in VLBI. The system was originally planned as an L-band radio telescope with a reflector made of metal grille and a design-dependent reception range up to a maximum of 15 GHz, but was initially equipped with S-band and X-band receivers for the moon missions, later with Ku-band and receivers for low frequencies like 300 and 610 MHz. The outer area of ​​the antenna dish consists of a metal grille that is reflective for the originally planned low frequencies, only the inner area with a diameter of 30 meters is lined with a smooth surface to receive the higher frequencies. 40 ° 33 '29.9 "  N , 116 ° 58' 36.1"  E

• 40 meters Kunming (KM40 or KRT40), operated by the Yunnan Astronomical Observatory (YNAO). Construction began in 2005 and commissioning in 2006. The station has receivers for S, C and X-band. and takes part in VLBI. 25 ° 1 '38.6 "  N , 102 ° 47' 44.9"  E

Stations in China since 2006

Additional antennas have been added since the Chang'e-1 lunar mission. The militarily managed deep space stations in Kashgar and Giyamusi took over the tracking and control of the lunar probes from Chang'e-3 (2013). During an exercise in July 2015, the technicians were able to use these two antennas to observe the flyby of NASA's New Horizons spacecraft over a distance of 4.76 billion kilometers and to determine its position. The newly built 65-m telescope in Tianma near Shanghai was also used for the Chang'e-3 mission. Since it, unlike the deep space stations Kashgar and Giyamusi, which are exclusively used for space travel, was only to be part of the lunar program for a time and was mainly used for radio astronomical observations , the lunar program was co- financed, as with Miyun and Kunming , here by the Chinese Academy of Sciences and the Shanghai City Government.

• 35-meter antenna in the desert 130 km south of Kashgar , S / X / Ka-band receiver, operated by the Kashgar deep-space station of the Xi'an satellite control center. 38 ° 25 '17 "  N , 76 ° 42' 51.8"  E
• 66 meter antenna in a wooded area 45 km southeast of Giyamusi , S / X band receiver, operated by the Giyamusi deep space station of the Xi'an satellite control center. 46 ° 29 '38 "  N , 130 ° 46' 14.2"  O .
• 65-meter Tianma radio telescope near Shanghai (SH65) operated by the Shanghai Astronomical Observatory. The antenna dish is fully movable and has adaptive adjustment of the surface with actuators for high geometric precision. The reception range is 1-50 GHz, and there are high-performance receivers for the frequency bands L, S, X, C, Ku, K, Ka, Q. Construction was decided in 2008, the foundation stone was laid at the end of 2009, construction began in 2010 Station at the end of 2012, the upper frequency bands were expanded by 2015. Height 79 meters, weight 2,700 tons. The station has Delta-DOR technology and takes part in VLBI. 31 ° 5 '31.6 "  N , 121 ° 8' 11.4"  E
• 40-meter radio telescope in Miyun (MRT40). The new radio telescope is right next to the 50-meter telescope. The telescope was tested and approved in 2017. Since then the facility has mainly been used for the Chang'e-5 mission and other astronomical observations. There are receivers for S, X and Ku bands. For the planned Mars mission, which is to be started in 2020, the two 40- and 50-meter antennas from Miyun with the future 70-meter antenna from Wuqing (WRT70) and the 40-meter antenna from Kunming (KRT40) for data reception can be interconnected to form an array.

The Chinese deep space network in 2013

The antenna network available for deep-space missions in 2013 looked like the sketch opposite. The 25-meter antenna in Sheshan was kept on standby for emergencies, but was no longer used. The military deep-space stations (green) with their transceivers have been in continuous use since the start of Chang'e-3 on December 1, 2013 and control the ultraviolet telescope onto the probe's lander, which is constantly used by the astronomers at the National Observatories. Since 2018, Chang'e-4 landers and rovers with their payloads have also been added.

According to the needs of the individual missions, the civil radio telescopes (blue) are switched on in individual cases. During the critical start phase, all of the stations shown on the map (including Zapala since Chang'e-4) in a VLBI network contribute to the precise location of the spacecraft. In 2018, only Kashgar and Giyamusi as well as Nanshan and Miyun were involved in placing the relay satellite “ Elsternbrücke ” in a halo orbit around the L ₂ point behind the moon. For receiving scientific data from the moon, the antennas are divided into Miyun and Kunming. While the civil and military networks were separate during the early moon missions, since 2013 all stations have been able to communicate directly with each other using the eVLBI software developed by the Shanghai Observatory .

Zapala deep space station in Argentina

Estación del Espacio Lejano

Station of the Chinese deep space network in Argentina

35 meter antenna of the Estación del Espacio Lejano

As early as 2010, the General Command for Satellite Starts, Track Tracking and Control (中国 卫星 发射 测控 系统 部), which was subordinate to the Central Office of the People's Liberation Army (since January 1, 2016, the Strategic Combat Support Force of the People's Republic of China ), the superior department of the Xi'an Satellite Control Center , had at the The Argentine Commission for Space Activities asked whether it would be possible to set up a ground station there, similar to the ESA station in Malargüe.

After the site was chosen, for tectonic reasons , among other things , the province of Neuquén on the northern edge of Patagonia . In 2012 the General Command for Satellite Launches signed a bilateral agreement with the Commission for Space Activities ( CONAE ) and a trilateral agreement with CONAE and the provincial government of Neuquén, in which it was agreed that the province of the People's Republic of China would have an area for the construction of a Would provide deep space station and the CONAE in return could use this large antenna for its own national and international projects and would be involved in the lunar program as well as the Mars program of the People's Republic of China .

On the basis of the agreement with the Neuquén Province, the Chinese Hafenbau GmbH (中国 港湾 工程 有限 责任 公司), a subsidiary of the China Communications Construction Company responsible for overseas projects , began excavation work on a 200 hectare site about 75 km north of the city at the end of 2013 Zapala . In China, the deep space station (Spanish estación del espacio lejano ) , which for technical reasons is far removed from any civilization, is named after this place (萨帕拉 深 空 站). In Argentina, Bajada del Agrio is usually used for the place name, a small place already in the Picunches department , which is about 20 km away from the station. Argentine public sources also use the term Estación de Espacio Profundo CLTC-CONAE-NEUQUÉN .

According to the final contract dated April 23, 2014, the station should only serve civil purposes, but is managed by the main department of satellite launches, trajectory tracking and control (中国 卫星 发射 测控 系统 部, Pinyin Zhōnggúo Wèixīng Fāshè Cèkòng Xìtǒng Bù , English China Satellite Launch and Tracking Control or CLTC ) of the Strategic Combat Support Force of the Chinese People's Liberation Army (中国人民解放军 战略 支援部队, Pinyin Zhōnggúo Rénmín Jiěfàngjūn Zhànlüè Zhīyuán Bùduì ) operated. Due to a lack of insight into the structures of Chinese space travel - there is no civil space travel in China, every television satellite and every lunar probe belongs to the People's Liberation Army - this leads to domestic political discussions in Argentina.

The construction work was largely completed in February 2017, and commissioning took place in April 2018. This station has extensive building complexes, its own power plant and is roughly on the opposite side of the world to China. Together with the stations on Chinese soil, the network has a sky coverage of 90%. The station has Delta-DOR technology for precise positioning of spacecraft together with the other deep space stations and is compatible with CCSDS.

The meeting on December 13, 2018. In the center left Major General Huang, right General Secretary Menicocci.

So far, two larger antennas have been implemented. 38 ° 11 ′ 27.3 ″  S , 70 ° 8 ′ 59.6 ″  W , 434 m

• 35 meter antenna, S / X / Ka-band receiver
• 13.5 meter antenna

The station was first used on the Chang'e 4 mission , which began on May 20, 2018 with the launch of the “ Elsternbrücke ” relay satellite .

The Zapala deep space station is operated by the Xi'an satellite control center and is primarily used for telemetry, orbit tracking and control of the lunar probes, and from 2020 also the Martian probe Tianwen-1 . In the contract of 2014, however, it was agreed that the Argentine Commission for Space Activities could use the antenna for 10% of the time for its own purposes, just as in the contract concluded by ESA with Argentina in 2009 for its ESTRACK station in Malargüe . Of course, only the time after the moonset in Argentina is available for this. On December 13, 2018, a Chinese delegation led by Major General Huang Qiusheng (黄秋生), the Political Commissar of the Department of Satellite Launches, Orbit Tracking and Control at the Strategic Combat Assistance Force of the People's Liberation Army, visited the CONAE headquarters in Buenos Aires to meet with Félix Menicocci, the Secretary General of the Commission for Space Activities to discuss the specific timetable (CONAE operates several reconnaissance satellites in orbit) and to explore possibilities for Argentina to participate in the Chinese lunar program.

Systems for radio astronomy

21 centimeter array (21CMA)

• The 15-meter radio telescope in Miyun was built in 1992 and used to study pulsars, but then dismantled around 2002 in favor of the 50-meter radio telescope.
• 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. It has been in operation since 1998. The system is located in the immediate vicinity of the 50-meter and 40-meter radio telescope. By activating the 50-meter antenna, the sensitivity can be increased by a factor of 2. 40 ° 33 '27.9 "  N , 116 ° 58' 36.1"  E

• FAST radio telescope , the radio telescope with the world's largest primary mirror. The total diameter of the immovable spherical main mirror is 500 meters; The signals can be effectively received over an area with a diameter of 300 meters (aperture). Due to its physical properties, this device can mainly be used for radio astronomy. However, FAST will play an important role in the 2020 Mars mission, not only because the telescope can receive the telemetry signals from interplanetary probes on its own due to its large aperture , but above all because of the frequency range of its receivers (70 MHz to 3 GHz). The Mars probe Tianwen-1 slows down with its landing from within 8 minutes of sonic velocity 14x to 0, which through the Doppler effect , the frequency of the carrier wave of the telemetry signals in the X-band changes greatly and rapidly. In the event of the sudden braking by opening the parachute, the regular deep-space stations will most likely lose contact with the probe and you will have to resort to decimeter wave communication, which is also not unproblematic . 25 ° 39 '11.5 "  N , 106 ° 51' 24.1"  E

• 21 Centimeter Array (21CMA) in Ulastai , Xinjiang . Completed in 2006, expanded in 2009 with new low-noise amplifiers and better computer technology for evaluation. Located in a remote valley, this array studies the low level emissions of neutral hydrogen from the HI line . The array consists of 81 groups (pods) with a total of 10287 antennas. These are arranged in two arms at right angles to each other, 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. All antennas are aimed at the ecliptic pole . 42 ° 55 '27.1 "  N , 86 ° 42' 57.6"  E

• Chinese Spectral Radio Heliograph (CSRH), renamed MUSER (MingantU SpEctral Radioheliograph) after completion. The CSRH is based on a joint evaluation of the data from 40 radio oteslescopes with a diameter of 4.5 m for the range 400 MHz to 2 GHz and 60 telescopes with a diameter of 2 meters for the range 2–15 GHz, arranged in three spiral arms. The location is in Inner Mongolia near Mingantu. The facility can create high-resolution radio astronomical maps in terms of time, space and spectra. Construction began in 2009 and the first light in 2013. 42 ° 12 ′ 38.2 ″  N , 115 ° 14 ′ 27 ″  E

Planned or under construction stations

• 110 meters Qitai , QTT radio telescope . When completed, it will be the world's largest fully articulated radio telescope and move the radio telescopes from Green Bank and Effelsberg into second and third place. 43 ° 36 '30.6 "  N , 89 ° 41' 5.3"  E
• 70 meters from Wuqing (WRT70) on the western outskirts of Tianjin . Specially built since 2018 to receive the payload data from the Mars probe Tianwen-1 via the X-band. Subordinate to the Beijing ground segment established in the main building of the National Astronomical Observatories of the Chinese Academy of Sciences for the Lunar Program of the People's Republic of China . The foundation stone was laid at the end of October 2018, and on April 25, 2020 the bowl was lifted onto the bogie.
• Kashi Station received three additional 35 m antennas for the Tianwen-1 Mars mission in 2020. These can be connected to an array, so that the antennas together achieve the performance of the 66-meter station from Giamusi. In July 2020, construction work on all three of the new antennas was completed. After adjustment and troubleshooting in the computer systems, the array is scheduled to start regular operation at the end of 2020.

Deep space antennas for space travel with a diameter of 30 m or more in comparison (as of Q3 2019)

	DSN (NASA)	CDSN	ESTRACK	Roscosmos	JAXA	ISTRAC
Existing plants	70 m 3 x 34 m 9 x	65 m 2 x 50 m 1 x 40 m 2 x 35 m 2 x	35 m 3 x	70 m 2 x 64 m 1 x	64 m 1 x 34 m 1 x	32 m 1x
Plants planned or under construction	34 m 2 x	110 m 1 x 70 m 1 x 35 m 3 x	32 m 1 x (Goonhilly) 35 m 1 x		54 m 1 x
Can be activated if required or backup systems	Parkes Observatory VLA Green Bank Arecibo	25 m 2 x NEARLY	national stations of the ESA states		30 m 1 x 20 m 1 x	18 m 1 x
Total (standard operation)	12	7th	3	3	2	1

Satellite tracking

In addition to the Chinese deep space network, there is also an extensive network of stations coordinated from the Xi'an satellite control center for fast tracking of satellites in low orbits and for spacecraft after launch such as Shenzhou 7 or manned space stations such as Tiangong 1 . The systems in it have smaller, fast-moving antennas in order to follow the objects moving quickly across the sky.

The following ground stations are currently (2019) active within the borders of China:

• Weinan , Shaanxi Province
• Changchun , Jilin Province
• Qingdao , Shandong Province
• Xiamen , Fujian Province
• Lushan , Sichuan Province
• Sanya , Hainan Province
• Nanning , Guangxi Autonomous Region
• Kashgar , Xinjiang Autonomous Region

The Minxi ground station in the province of Fujian, built in 1967, is normally no longer used for tracking purposes and is only kept as a reserve. Otherwise, Minxi is responsible for the connection work between the individual ground stations.

Tracking stations deployed on the return of a lunar probe

There are also stations in Jiuquan and Jinta, which is about 50 km northeast of it, as well as the Dongfeng ground station located directly at the Jiuquan Cosmodrome in Inner Mongolia , also known as the Alxa ground station after the aimag or Bund in which the cosmodrome is located . However, these are only activated during rocket launches and, above all, when tracking unmanned and manned return capsules on the approach to the Dörbed landing site north of Hohhot . The Wudan ground station in the Ongniud banner is also only activated temporarily .

In Qakilik , Xinjiang Autonomous Region, an X-band radar station with a phased array antenna was built for the return phase of the lunar program . The Sênggê Zangbo Astronomical Observatory in Ngari (Western Tibet) was also equipped with a beacon system and a mobile multi-beam remote monitoring and control device for the return phase of the lunar program . There are also two mobile surveillance teams, one of which is normally stationed at the Dörbed landing site, the other in Khotan in southern Xinjiang.

When rockets are launched from the Wenchang Cosmodrome , the tracking stations on Bronze Drum Mountain (铜鼓岭, Pinyin Tónggǔ Lǐng ) not far from the Cosmodrome and those on Duncan, one of the Paracel Islands , are activated. Outside of China, there are tracking stations in Karachi ( Pakistan ), Malindi ( Kenya ), Swakopmund ( Namibia ) and Santiago de Chile .

Tracking ships

The Yuan Wang 6 in 2011

In addition to the fixed stations, there are currently (2019) five tracking ships of the Yuan-Wang class (远望 号, Pinyin Yuǎn Wàng Hào , lit. "looking into the distance"), one of which is moored stationary at its home base in Jiangyin the satellite control center Xi'an , i.e. the main department of satellite launches, orbit tracking and control (卫星 发射 测控 系统 部, Pinyin Wèixīng Fāshè Cèkòng Xìtǒng Bù ) of the Strategic Combat Support Force of the People's Liberation Army . The track tracking ships are each equipped with three movable parabolic antennas that work like a single large dish via interferometry. It is mainly used for tracking rockets after launch and for satellites in low and medium (less than 2000 km or between 2000 km and 36,000 km) and geostationary (35,786 km) orbits. The tracking ships operate on the S and C bands of the microwave range . In order to increase the measurement accuracy, the tracking ships are equipped with fin stabilizers that limit the roll of the ship in wind and swell to 3 °. But as the ship still fluctuates, the devices are with a laser gyro - Inertial Navigation System features that automatically deducts these fluctuations. For example, during missions where constant data transmission between ship and satellite is necessary, for example operations with reconnaissance satellites of the Yaogan series (遥感 xx 号), one of the parabolic antennas can automatically remain aligned with the satellite.

In cooperation with the reconnaissance satellites, the tracking ships can detect the launch of ICBMs at an early stage.

Tracking ships

Surname	length	width	Draft	height	Standard displacement	Manufacturer	Launch	Commissioning	Deactivation	status
Yuan Wang 1	191 m	22.6 m	9 m	38 m	21,000 t	Jiangnan Shipyard	August 31, 1977	Early 1980	November 26, 2011	Donated to the Jiangnan Shipyard Museum in Shanghai .
Yuan Wang 2	191 m	22.6 m	9 m	38 m	21,000 t	Jiangnan Shipyard	October 1977	Early 1980		It has been moored to a quay at Base 23 ( Jiangyin ) since December 2010 , and acts there as a fixed ground station for monitoring and controlling the regular satellite functions.
Yuan Wang 3	180 m	22.2 m	8 m	37.8 m	17,000 t	Jiangnan Shipyard	April 26, 1994	May 18, 1995		Ocean service
Yuan Wang 4	156.2 m	20.6 m	7.5 m	39 m	12,000 t	Chengxi repair yard	August 1998	1999	January 2011	Sunk during a target exercise with a Dongfeng 21D medium-range missile.
Yuan Wang 5	222.2 m	25.2 m	8.2 m	40.85 m	25,000 t	Jiangnan Shipyard	September 2006	September 29, 2007		Ocean service
Yuan Wang 6	222.2 m	25.2 m	8.2 m	40.85 m	25,000 t	Jiangnan Shipyard	March 16, 2007	July 2008		Ocean service
Yuan Wang 7	224.9 m	27.2 m		44.2 m	27,000 t	Jiangnan Shipyard	15th October 2015	July 12, 2016		Ocean service

Relay satellites

China has several relay satellites of the Tianlian series (currently consisting of the Tianlian 1 and Tianlian 2 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 to have. 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 spaceships 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 the probe's telemetry data.

Individual evidence

1. ↑ 王 美 et al .: 深 空 测控 网 干涉 测量 系统 在 “鹊桥” 任务 中 的 应用 分析. In: http://jdse.bit.edu.cn/ . Retrieved May 23, 2019 (Chinese). 
2. ↑ 董光亮 、 李海涛 et al .: 中国 深 空 测控 系统 建设 与 技术 发展. In: http://jdse.bit.edu.cn/ . March 5, 2018, Retrieved May 23, 2019 (Chinese). 
3. ↑ 董光亮 、 李海涛 et al .: 中国 深 空 测控 系统 建设 与 技术 发展. In: http://jdse.bit.edu.cn/ . March 5, 2018, Retrieved May 20, 2019 (Chinese). 
4. ↑ Please note: While MT Mechatronics from Mainz, which was already involved in the construction of the 100 m radio telescope Effelsberg , tried to get the order for the 100 m telescope in Qitai and would of course have to pay in euros, the Most of the systems shown here are based on domestic technology. When assessing the costs, the exchange rate is not to be taken into account, but the purchasing power, where one yuan is about one euro. The Chinese government is really spending a lot of money here.
5. Jump up ↑ Andrew Jones: Mars, asteroids, Ganymede and Uranus: China's deep space exploration plan to 2030 and beyond. In: gbtimes.com. July 14, 2017, accessed June 22, 2019 . 
6. ↑ 科技 创新 2030— 重大 项目 （16 个 项目 ， 已 启动 4 个 项目）. In: sciping.com. September 5, 2018, Retrieved May 25, 2019 (Chinese). 
7. ↑ 董光亮 、 李海涛 et al .: 中国 深 空 测控 系统 建设 与 技术 发展. In: jdse.bit.edu.cn. March 5, 2018, Retrieved May 25, 2019 (Chinese).  This article was published in the Deep Space Exploration (深 空 探测 学报) magazine published by the Ministry of Industry and Information Technology (工业 和 信息 化 部). So it is an official government announcement.
8. ↑ 专家 人才 库 洪晓瑜. In: sourcedb.shao.cas.cn. Retrieved February 26, 2019 (Chinese). 
9. ↑ Introduction. In: http://radio-en.shao.cas.cn/ . Retrieved May 24, 2019 . 
10. ↑ 王 美 et al .: 深 空 测控 网 干涉 测量 系统 在 “鹊桥” 任务 中 的 应用 分析. In: jdse.bit.edu.cn. Retrieved May 23, 2019 (Chinese). 
11. ↑ 40 米 射 电 望远镜 介绍. In: ynao.cas.cn. January 6, 2012, accessed May 27, 2019 (Chinese). 
12. ↑ 陈云芬 、 张 蜀 新: “嫦娥奔月” 云南省 地面 主干 工程 已 基本 完成. In: news.sina.com.cn. March 17, 2006, Retrieved May 27, 2019 (Chinese). 
13. ↑ C. Jin et al .: An Introduction to the Miyun 50m Radio Telescope. (PDF) In: zmtt.bao.ac.cn. Retrieved July 12, 2019 . 
14. ^ Shanghai Astronomical Observatory. Retrieved November 17, 2017 . 
15. ^ The 25m Radio Telescope Observing Station - Shanghai Astronomical Observatory, Chinese Academy of Sciences. Retrieved November 25, 2017 . 
16. ^ Xinjiang Astronomy Observatory - Chinese Academy of Sciences. Retrieved November 19, 2017 . 
17. ^ Nanshan VLBI Station Report for 2005 . ( nasa.gov [PDF]).
18. ↑ Organization. In: https://www.evlbi.org/ . Retrieved April 6, 2019 . 
19. ↑ CSIRO Australia Telescope National Facility: Equipment Built At The Dish Goes To China. May 20, 2020, accessed on July 6, 2020 . 
20. ^ Na Wang: Large Radio Telescopes In China . ( atnf.csiro.au [PDF]).
21. ↑ C. Jin, H. Wang, X. Zhan: An Introduction to the Miyun 50m Radio Telescope . February 2003 ( zmtt.bao.ac.cn [PDF]).
22. ↑ Astronomy 2018. Retrieved October 19, 2019 . 
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30. ^ Lunar-based Ultraviolet Telescope (LUT). In: http://english.nao.cas.cn/ . Retrieved May 28, 2019 . 
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36. ↑ 吕炳宏 、 安普忠: 中国 深 空 测控 网 为 “天 问 一号” 探 火 之 旅 提供 全程 测控 支持. In: spaceflightfans.cn. July 24, 2020, accessed July 24, 2020 (Chinese).  The photos show, from top to bottom, the three military deep-space stations in Kashgar, Giyamusi and Zapala. The bottom photo was taken at the Xi'an Satellite Control Center .
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41. ↑ 王俊: 战略 支援部队 政工 部 副 主任 黄秋生 少将 已 转 任 航天 系统 部 副 政委. In: https://www.thepaper.cn/ . August 28, 2018, Retrieved May 27, 2019 (Chinese). 
42. ↑ According to the 2014 contract, Zapala should only serve civilian purposes. It must therefore be ensured that no photos of the Malvinas / Falkland Islands etc. taken by SAOCOM 1A are received via this station .
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50. ^ Qian Zheng, Xiang-Ping Wu, Melanie Johnston-Hollitt, Jun-hua Gu, Haiguang Xu: Radiosources in the NCP Region Observed with the 21 Centimeter Array. 2016, arxiv : 1602.06624v3 ( arxiv.org [PDF]).
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54. ↑ 刘建军: 中国 首次 火星 探测 任务 地面 应用 系统. In: jdse.bit.edu.cn. May 5, 2015, accessed July 8, 2019 (Chinese). 
55. ^ Lunar Exploration Program Ground Application System. In: english.nao.cas.cn. Accessed July 10, 2019 . 
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59. ↑ 吕炳宏 、 付毅飞: 中国 深 空 测控 网 将 全程 护送 “天 问 一号” 探 火. In: stdaily.com. July 24, 2020, accessed July 24, 2020 (Chinese).  The photo shows the finished array in July 2020.
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61. ↑ This includes the radio telescopes of astronomical institutes and national space organizations z. B. the RT Effelsberg , ground station Weilheim , Jodrell Bank , Sardinia Radio Telescope etc.
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Web links

• Development and Future of the Chinese Deep Space TT&C System (in Chinese with English summary)
• Official website of the European VLBI Network (in English)

 Map with all coordinates: OSM | WikiMap