Space Debris Research Progress of China

LIU Jing JIANG Hai YANG Xu LI Fen ZHAO Nanying

Space Debris Research Progress of China

LIU Jing1,2,3JIANG Hai1,2YANG Xu1,2,3LI Fen1,2ZHAO Nanying1,2

1 (100101) 2 (100101) 3 (100049)

The rapid increase of space debris population has posed serious threaten to the safety of human space activities and became a global issue. How to enhance the technical capabilities of space debris threat coping ability is of great significance to the sustainable development of space activities, the further development, and utilization of outer space. In this paper, we describe space debris research progress of China on observation, collision avoidance, protection, mitigation, regulation, and standard during the last twenty years, and look forward to the future development direction of space debris.

Space debris, Observation, Collision avoidance, Protection, Mitigation

1 Introduction

Since the first space launch in 1957, a total of 7985 space launch activities has been conducted by the end of July 2020, 9900 spacecraft and 6121 rockets have been successfully launched into Earth orbit. As a result of these space activities, the Earth orbit space has been filled with space objects. Most of them are space debris except for some operational spacecraft. So far, there have been more than 500 on-orbit bre-a-k-up events, which are the main source of space debris, and the defunct spacecraft are another important source of space debris, the other sources of debris include the wreckage of launch vehicle, mission related debris, tiny paint spots on the exterior of spacecraft, and rocket components,.

According to the European Space Agency, the number of space debris larger than 10 cm has exceeded 34000, larger than 1 cm has exceeded 900000, and larger than 1 mm is hundreds of millions(https://www.esa.int/Safety_Security/Space_Debris/ Space_debris_by_the_numbers). Because of the high speed of space debris up to 8 kms–1, a collision with even a 1 cm space debris can damage or even destroy a spacecraft. In addition, according to statistic data published by the United States, there are about 400 debris reentered into the atmosphere each year, the maximum exceeds 1000. The reentry of large space objects also poses serious threat to the safety of human beings and ground properties (https://www.space-track.org/#decay)

2 Current Research Status

Space debris poses serious threat to the on-orbit space activities and has become an international focus and hot issue. To ensure the long-term sustainability of outer space activities, space debris research has been carried out by the major spacefaring nations in observation, collision avoidance, protection, mitigation, and regulation and standard to improve technical capabilities over the past few years. United States has established a global Space Surveillance Network, which can fully catalog space debris larger than 10 cm. Russia also has its own network, and plays a leading role in high-earth-orbit object observation. ESA proposed its space situation awareness program in 2009 and formed an observation network composed of several radars and telescopes, which can observe space debris larger than 5 cm in Low-Earth- Orbit (LEO) and 50 cm in high-Earth-orbit. In addi-tion, Surrey Space Center of United Kingdom and many European research institutions successfully launched a test satellite from International Space Station to implement the RemoveDEBRIS project in 2018.

Since 1995, China National Space Administration officially joined Inter-Agency Space Debris Coordination Committee (IADC), continuously conducted space debris research work and actively participated in international cooperation, has achieved a series of important and influential results, laid a solid technical foundation to effectively respond to space emergent events and support international cooperation. Based on the above mentioned, this paper sum-marizes the main progress of space debris research in China during the last twenty years on observation, collision avoidance, protection, mitigation, and regul-ation and standard, and looks forward to the future works.

3 Space Debris Research Achievements

Since China National Space Administration (CNSA) launched the Space Debris Research Project in 2000, China has achieved a series of important results in five aspects, observation, collision avoidance, protection, mitigation, regulation, and standard, respec-tively.

3.1 Observation

China draws lessons from the international advanced experience and actively promotes the research and development of observation architecture, infrastruc-ture, and technology. We have finished the demonstration of space and ground-based observation network, studied the key technologies for small-size debris observation, high-precision detection and imag-ing, developed prototypes, preliminarily established the space debris emergency observation network, as shown in Figure 1. Based on the above mentioned, we have developed a reliable space debris observation facility performance evaluation model, which can accurately evaluate the performance of space debris facilities of the network, and optimize scheduling the network timely. We have broken th-r-ough key technologies on telescope remote operation, optimal scheduling of joint observation network, and cooperative emergency observation network, which can efficiently improve the response to space debris emergency events.

Fig. 1 Space debris emergency observation network of China

3.2 Collision Avoidance

Space Debris Observation and Data Application Ce-n-ter (SDOAC) of CNSA was established in the Chinese Academy of Sciences in June 2015. SDOAC is responsible for the operation and management of space debris and near-Earth object observation facilities, space debris observation database maintenance, as well as on-orbit conjunction analysis and collision avoidance, space debris mitigation policy, standard and regulation research, and international cooperation activities on space debris and near-Earth object research.

The center established a collision avoidance model based on independent data, conducted in-depth research on risk assessment methods, formed an auto-nomous collision avoidance procedure (Figure 2), and established a space debris application and service system (Figure 3), which can be used to evaluate space debris impact of spacecraft’s entire lifetime, support space events observation and response, and conduct mission planning and performance evaluation for the joint space and ground-based observation facilities and network, and can provide launch collision avoidance, on-orbit collision avoidance maneuver design, mission design and performance evaluation for post mission disposal, reentry safety analysis, and space debris events identification. SDOAC independently developed China’s first space debris long-term evolution model-SOLEM[1], continuously participates in IADC cooperative research, has rea-ched an advanced international level, can provide analysis support for mitigation measures, and plan and design missions to actively remove debris. The key technologies have been broken through during the development and application of the system, laying the foundation for the formulation of technical standards for space debris collision avoidance.

SDOAC has provided services for many space events, successfully eliminated two times of false alarm of Venezuelan 1 remote sensing satellite based on our analysis results, efficiently coordinated the SJ-11 satellite to avoid the threat of collision, achieved excellent results in IADC joint reentry campaigns, such as TG-1 reentry campaign, provided de-orbits mission design and post evaluation service to CHINASAT 5A. In addition, SDOAC provides consulting services for satellite and constellation mission design, evaluates space debris mitigation measures, and supports space emergency event analysis and satellite failure analysis.

3.3 Protection

China Academy of Space Technology has researched the method of Meteoroid/Orbital Debris (M/OD) risk assessment and developed the Meteoroid and Orbital Debris Assessment and Optimization Sy-s-tem Tools (MODAOST), which has been successfully applied in China’s Manned Spacecraft and acce-pted by international counterparts. The results have been published in the Protection Manual of IADC[2].

Fig. 2 Workflow of joint collision avoidance

Fig. 3 Typical scenarios of the space debris application and service system

Fig. 4 Resistance sail of BP-1B

Harbin Institute of Technology (HIT) has led the development of the spacecraft survivability assessment system S3DE[3], which is compatible with data formats of typical space debris engineering models (ORDEM, MASTER, and SDEEM), and has the preliminary capability to evaluate and calculate the spacecraft survivability. Besides, HIT has analyzed the generation, evolution, and spatial-temporal distribution of space debris, developed the LEO-to- GTO space debris environment engineering model, built the LEO-to-GTO spacecraft environment ana-l-ysis system on space debris and meteoroids[4].

Fig. 5 Deorbit sail of Taurus

3.4 Mitigation

In 2016, China Academy of Launch Vehicle Te-chnology conducted the first on-orbit active debris removal experiment with AL-1 spacecraft (https://www.guancha.cn/Science/2016_06_26_365454.shtml). HIT has studied the folding and unfolding active control technology for the inflation resistance increase device, verified the compatibility of the device to the space environment, and provided a reliable deorbit method for LEO micro-satellites and satellite constellations which may out of control[5].

In order to meet the requirements of IADC Space Debris Mitigation Guidelines, Beijing Institute of Technology (http://www.bit.edu.cn/xww/zhxw/ 173330.htm) and Shanghai Institute of Aerospace Technology (http://www.chinanews.com/gn/2019/ 09-12/8954806.shtml) added drag sail and deorbit sail devices to spacecraft as shown in Figure 4 and Figure 5, and successfully verified the reliability of the LEO fast deorbit technology and the deorbit device, which provides practical experience for the small satellites and satellite constellations to efficiently conduct post- mission disposal.

3.5 Regulation and Standard

China has also actively participated in the compilation of the IADC Space Debris Mitigation Guidelines, and issued the Chinese Space Debris Mitigation and Protection Management Measures[6]. The Measures stipulate the subjects and requirements involved in the entire process of spacecraft development, design, development and production, on-orbit operations, and post-mission disposal, detailed the seven requirements of the United Nations Space Debris Mitigation Guidelines, and presented the implementation requirements. Now, the Measures is a national regulation of China’s space development and operational departments, which is a critical element to pass the review of the spacecraft launch license.

China’s space debris standard system has been preliminarily established with the support of China’s space debris research projects, which includes standards for management, protection, mitigation, obse-r-vation, and collision avoidance as shown in Figure 6, and nearly 50 draft standards have been formed. In 2020, the Subcommittee 5 on Space debris of National Technical Committee 425 on Space Technology and Operation of Standardization Administration of China has been established, with members from government, industries, academies, universities, and commercial entities, including space activity managers, spacecraft producers, satellite operators, scientific researchers and space data users,. The extensive coverage of the Subcommittee members also lays a personnel foundation for the integrity of the space debris standard system and the feasibility of standard specification formulation. As the National Space Debris Standardization Technical Organization, the Subcommittee will carry out the formulation and revision of national standards in the aspects of space debris observation, collision avoidance, protection and mitigation, and will connect with the ISO/TC20/SC14, meet the international space debris mitigation requirements, and facilitate the long-term sustainability of outer space activities.

Fig. 6 Diagram of China’s space debris standard system

4 Future Works

In recent years, with the continuously development of space technology, various giant constellation plans have been proposed. In the future, more spacecraft will enter space and the collision probability will greatly increase. The safety of space assets will face more severe challenges. Therefore, in response to the increasingly complex requirements of the space environment, the development of space debris observation should take our current status into consideration, develop a space-ground coordinated observation system, and develop miniaturized, low-cost space-based observation facility to gradually improve the small debris observation capability. At the same time, we will coordinate existing technical foundation in the aspects of observation, collision avoidance, protection, and mitigation, strengthen research on new technologies related space debris, and establish a reliable dynamic database of space debris environment to support the safe, rapid and sustainable development of space activities, and support China’s deep participation in the international cooperation on space debris.

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LIU Jing, JIANG Hai, YANG Xu, LI Fen, ZHAO Nanying. Space Debris Research Progress of China., 2020, 40(5): 956-961. DOI:10.11728/cjss2020.05.956

August 25, 2020

E-mail: liujing@bao.ac.cn