# Shiyan (satellite)

Shiyan (SY, simplified Chinese: 实验; traditional Chinese: 實驗; pinyin: Shíyàn; lit. 'experiment') is a Chinese experimental satellite program consisting of a variety of test satellites. Given the classified nature of the satellites, Chinese government statements regarding the missions of Shiyan satellites follow the common refrain of agricultural monitoring and space environment observation — the same offered for other classified programs such as the Tongxin Jishu Shiyan, Yaogan, and Shijian programs. Alternatively named Tansuo satellites, Shiyan satellites occupy varying orbits including low Earth, polar Sun-synchronous, geosynchronous, and highly-elliptical orbits and are believed to accomplish a diverse set of missions from rendezvous proximity operations (RPO) to earth imaging. Though similarly named, the Shiyan satellite program is not to be confused with the separate Shijian satellite program.

## Notable satellites
### Shiyan 7

Shiyan 7 was launched from Taiyuan Satellite Launch Center (TSLC) on 19 July 2013 aboard a Launch March 4C rocket into low Earth, Sun-synchronous orbit, accompanied by the Shijian 15 (of unknown mission) and Chuangxin 3. Three weeks after launch, from 6–9 August 2013, Shiyan 7 performed rendezvous operations with its companion payload, Chuangxin-3, supporting speculations of a robotic arm-wielding satellite tasked with rendezvous proximity operations (RPO). Later, Shiyan 7 shifted to rendezvous with Shijian 7 (of unknown mission) with whom it maintained proximity from 19 to 20 August 2013 until it maneuvered into a 5 km lower orbit. Drawing further suspicion, around 19 October 2013, Shiyan 7 maneuvered to a 1 km higher orbit and released a previously untracked object, designated Shiyan 7B which many believe to be a subsatellite to RPO experiments. Such operations, which the Chinese government does not comment on, has sparked debate around the nature of Chinese experimental satellites.

## Satellites

| Name | Launch | Orbit | Orbital apsis | Inclination | SCN | COSPAR ID | Launch site | Launcher | Status |
| Shiyan 1 | 18 April 2004 | SSO | 559.8 km × 572.9 km | 98.0° | 28220 | 2004-012A | XSLC | Long March 2C | Operational |
| Shiyan 2 | 18 November 2004 | SSO | 678.9 km × 702.5 km | 98.1° | 28479 | 2004-046A | XSLC | Long March 2C | Operational |
| Shiyan 3 | 5 November 2008 | SSO | 788.6 km × 809.7 km | 98.7° | 33433 | 2008-056A | JSLC | Long March 2D | Operational |
| Shiyan 4 | 20 November 2011 | SSO | 781.6 km × 816.2 km | 98.7° | 37931 | 2011-068B | JSLC | Long March 2D | Operational |
| Shiyan 5 | 25 November 2013 | SSO | 747.5 km × 770.0 km | 98.2° | 39455 | 2013-068A | JSLC | Long March 2D | Operational |
| Shiyan 6-01 | 19 November 2018 | SSO | 448.8 km × 541.0 km | 97.4° | 43711 | 2018-094B | JSLC | Long March 2D | Operational |
| Shiyan 6-02 | 4 July 2020 | SSO | 609.0 km × 799.1 km | 98.2° | 45859 | 2020-043A | JSLC | Long March 2D | Operational |
| Shiyan 6-03 | 8 April 2021 | SSO | 1,001.4 km × 1,126.5 km | 99.5° | 48157 | 2021-028A | TSLC | Long March 4B | Operational |
| Shiyan 7A | 19 July 2013 | SSO | 665.3 k × 679.0 km | 98.0° | 39208 | 2013-037A | TSLC | Long March 4C | Operational |
| Shiyan 7B (subsat) | 19 July 2013 | SSO | 670 km × 660 km | 98.0° | 39357 | 2013-037J | TSLC | Long March 4C | Operational |
| Shiyan 9 | 11 March 2021 | GTO | 35,738.5 km × 35,852 km | 19.4° | 47851 | 2021-019A | WSLC | Long March 7A | Operational |
| Shiyan 10 | 27 September 2021 | Molniya | 1,422.3 km × 38,950.6 km | 63.7° | 49258 | 2021-087A | XSLC | Long March 3B | Partially operational |
| Shiyan 10-02 | 29 December 2022 | GTO | (Not yet announced) | (Not yet announced) | 54878 | 2022-178A | XSLC | Long March 3B | Operational |
| Shiyan 11 | 24 November 2021 | SSO | 488.9 km × 502.0 km | 97.5° | 49501 | 2021-112A | JSLC | Kuaizhou 1A | Operational |
| Shiyan 12-01 | 23 December 2021 | GEO | 35,751.6 km × 35,758.8 km | 0.2° | 50321 | 2021-129A | WSLC | Long March 7A | Operational |
| Shiyan 12-02 | 23 December 2021 | GEO | 35,749.1 km × 35,773.1 km | 0.2° | 50322 | 2021-129B | WSLC | Long March 7A | Operational |
| Shiyan 13 | 17 January 2022 | SSO | 371.3 km × 1,272.0 km | 98.6° | 51102 | 2022-004A | TSLC | Long March 2D | Operational |
| Shiyan 14 | 24 September 2022 | SSO | 492.1 km × 514.7 km | 97.5° | 53884 | 2022-118A | TSLC | Kuaizhou 1A | Operational |
| Shiyan 15 | 24 September 2022 | SSO | 491.8 km × 510.5 km | 97.5° | 53885 | 2022-118B | TSLC | Kuaizhou 1A | Operational |
| Shiyan 16A | 26 September 2022 | SSO | 509.1 km × 528.0 km | 97.5° | 53948 | 2022-121A | TSLC | Long March 6 | Operational |
| Shiyan 16B | 26 September 2022 | SSO | 509.6 km × 526.8 km | 97.5° | 53949 | 2022-121B | TSLC | Long March 6 | Operational |
| Shiyan 17 | 26 September 2022 | SSO | 508.1 km × 527.0 km | 97.5° | 53950 | 2022-121C | TSLC | Long March 6 | Operational |
| Shiyan 19 | 15 March 2023 | SSO | 500.1 km × 520.9 km | 97.5° | 55861 | 2023-034A | JSLC | Long March 11 | Operational |
| Shiyan 20A | 12 December 2022 | LEO | 800.3 km × 806.6 km | 60.0° | 54699 | 2022-169A | JSLC | Long March 4C | Operational |
| Shiyan 20B | 12 December 2022 | LEO | 798.5 km × 808.1 km | 60.0° | 54700 | 2022-169B | JSLC | Long March 4C | Operational |
| Shiyan 20C | 29 October 2022 | LEO | 799.5 km x 816.0 km | 60.0° | 54214 | 2022-142A | JSLC | Long March 2D | Operational |
| Shiyan 21 | 16 December 2022 | LEO | 480.8 km × 498.5 km | 36.0° | 54752 | 2022-172A | XSLC | Long March 11 | Operational |
| Shiyan 22A | 13 January 2023 | LEO | 504.3 km × 521.9 km | 43.2° | 55242 | 2023-006A | JSLC | Long March 2D | Operational |
| Shiyan 22B | 13 January 2023 | LEO | 510.6 km × 526.3 km | 43.2° | 55243 | 2023-006B | JSLC | Long March 2D | Operational |
| Shiyan 23 | 11 May 2024 | SSO | 624.6 km × 633.8 km | 97.8° | 59728 | 2024-089A | JSLC | Long March 4C | Operational |
| Shiyan 24A | 7 June 2023 | SSO | | | | | JSLC | Kinetica 1 | Operational |
| Shiyan 24B | 7 June 2023 | SSO | | | | | JSLC | Kinetica 1 | Operational |
| Shiyan 24C-01 | 25 December 2023 | SSO | 583.9 km × 589.3 km | 97.3° | 58650 | 2023-206A | Bo Run Jiu Zhou platform, South China Sea | Long March 11 | Operational |
| Shiyan 24C-02 | 25 December 2023 | SSO | 584.4 km × 588.5 km | 97.3° | 58651 | 2023-206B | Bo Run Jiu Zhou platform, South China Sea | Long March 11 | Operational |
| Shiyan 24C-03 | 25 December 2023 | SSO | 584.7 km × 587.9 km | 97.3° | 58652 | 2023-206C | Bo Run Jiu Zhou platform, South China Sea | Long March 11 | Operational |
| Shiyan 25 | 20 June 2023 | SSO | 272.5 km × 288.2 km | 96.5° | 57047 | 2023-087A | TSLC | Long March 6 | Operational |
| Shiyan 26A | 11 November 2024 | SSO | | | | | JSLC | Kinetica 1 | Operational |
| Shiyan 26B | 11 November 2024 | SSO | | | | | JSLC | Kinetica 1 | Operational |
| Shiyan 26C | 11 November 2024 | SSO | | | | | JSLC | Kinetica 1 | Operational |
| Sources: NASA, US Space Force, CelesTrak ||||||||||