L׳ADROIT – A spaceborne ultraviolet laser system for space debris clearing

Small (1–10 cm) debris in low Earth orbit (LEO) are extremely dangerous, because they spread the breakup cascade. Pulsed laser active debris removal using laser ablation jets on target is the most cost-effective way to re-enter the small debris. No other solutions address the whole problem of large (~100 cm, 1 t) as well as small debris. Physical removal of small debris (by nets, tethers and so on) is uneconomical because of the energy cost of matching orbits. In this paper, we present a completely new proposal relative to our earlier work. This new approach uses rapid, head-on interaction in 10–40 s rather than 4 minutes, using 20–40 kW bursts of 100 ps, 355 nm UV pulses from a 1.5 m diameter aperture on a space-based station in LEO. The station employs “heat-capacity” laser mode with low duty cycle to create an adaptable, robust, dual-mode system which can lower or raise large derelict objects into less dangerous orbits, as well as clear out the small debris in a 400-km thick LEO band. Time-average laser optical power is less than 15 kW. The combination of short pulses and UV wavelength gives lower required fluence on target as well as higher momentum coupling coefficient. An orbiting system can have short range because of high interaction rate deriving from its velocity through the debris field. This leads to much smaller mirrors and lower average power than the ground-based systems we have considered previously. Our system also permits strong defense of specific assets. Analysis gives an estimated cost less than $1 k each to re-enter most small debris in a few months, and about 280 k$ each to raise or lower 1-ton objects by 40 km. We believe it can do this for 2000 such large objects in about four years. Laser ablation is one of the few interactions in nature that propel a distant object without any significant reaction on the source.     

ICAN: A novel laser architecture for space debris removal

The development of a fiber based laser architecture will enable novel applications in environments which have hitherto been impossible due to size, efficiency and power of traditional systems. Such a new architecture has been developed by the International Coherent Amplification Network (ICAN) project. Here we present an analysis of utilizing an ICAN laser for the purpose of tracking and de-orbiting hyper-velocity space debris. With an increasing number of new debris from collisions of active, derelict and new payloads in orbit, there is a growing danger of runaway debris impacts. Due to its compactness and efficiency, it is shown that space-based operation would be possible. For different design parameters such as fiber array size, it is shown that the kHz repetition rate and kW average power of ICAN would be sufficient to de-orbit small 1–10 cm debris within a single instance via laser ablation.     

激光驱动接力移除空间碎片的小卫星星座及可行性研究

在众多空间碎片移除技术中,天基激光烧蚀驱动是一种高效的、有广阔应用前景的移除技术,特别是针对移除海量的、尺寸在1~10 cm的危险碎片而言,更是具有独特优势。然而,这一技术对高能激光器单脉冲能量、光束质量、发射镜口径等要求很高,目前的硬件水平还达不到实用指标要求,制约了其天基应用。为了克服这些硬件技术障碍,本文另辟蹊径,利用小卫星概念,提出了由不同轨道高度小卫星平台组成小卫星星座,通过在每个小卫星平台上的激光驱动接力来逐步降低碎片轨道高度,最终达到移除空间碎片的小卫星接力移除星座的构想。基于现有的激光器性能参数,根据激光烧蚀驱动碎片动力学模型计算了单个卫星平台的移除能力,结果显示,10 J单脉冲能量激光器和0.5 m直径发射镜,能够对20 km范围内、尺寸小于10 cm碎片进行有效驱动。进而,针对空间碎片密集度高而应用最广的800 km轨道高度区域,设计了由分布在不同轨道高度的30颗小卫星组成接力驱动移除星座系统方案,通过仿真模拟计算验证了星座系统的移除碎片的可行性。该研究利用目前热门的小卫星星座,降低了天基激光移除空间碎片技术对硬件的性能要求,为该技术的应用提供了新的思路和途径,所提出的小卫星接力驱动星座系统方案也有工程参考价值。     

A laser-optical system to re-enter or lower low Earth orbit space debris

Collisions among existing Low Earth Orbit (LEO) debris are now a main source of new debris, threatening future use of LEO space. Due to their greater number, small (1–10 cm) debris are the main threat, while large (>10 cm) objects are the main source of new debris. Flying up and interacting with each large object is inefficient due to the energy cost of orbit plane changes, and quite expensive per object removed. Strategically, it is imperative to remove both small and large debris. Laser-Orbital-Debris-Removal (LODR), is the only solution that can address both large and small debris. In this paper, we briefly review ground-based LODR, and discuss how a polar location can dramatically increase its effectiveness for the important class of sun-synchronous orbit (SSO) objects. With 20% clear weather, a laser-optical system at either pole could lower the 8-ton ENVISAT by 40 km in about 8 weeks, reducing the hazard it represents by a factor of four. We also discuss the advantages and disadvantages of a space-based LODR system. We estimate cost per object removed for these systems. International cooperation is essential for designing, building and operating any such system.     

天基照相跟踪空间碎片批处理轨道确定研究

随着国内外天基观测空间碎片研究的展开,文章提出了利用跟踪卫星的CCD(Charge
Coupled Device)相机对空间碎片进行轨道探测的方法,首先建立了CCD照相观测模型和基于 照相观测 的空间碎片批处理轨道确定模型。通过对CCD相机底片归算方法的分析可知,利用
CCD相机所获得的观测数据与跟踪卫星的姿态无关,且其精度只与测量和坐标转换计算的精 度有关,在测量和计算中可获得较高的精度。分别对分布密度较高的低轨道和地球同步 轨道区域的空间碎片进行了定轨分析。仿真结果表明,定轨时采用两个跟踪弧段的照相数据 定轨精度大大高于一个弧段照相数据的定轨精度;跟踪卫星距离空间碎片越近,定轨精度越 高;低轨道空间碎片的定轨精度高于地球同步轨道上的空间碎片定轨精度。
     

Space debris and the need for space traffic control

This report summarises the presentations which took place at the ‘Space Traffic Control – Is the Space Debris Problem Solvable?’ conference hosted by the Royal Aeronautical Society on the 2nd July 2013. The conference sought to promote discussion over methods to deal with the issue of space debris in particular and speakers included representatives from the European Space Agency, the United Kingdom Space Agency, practitioners and academia. Themes which emerged during the conference included the urgency of the problem of space debris, the need for short-term and long-term solutions, the necessity for the development and implementation of space debris remediation technologies to complement existing mitigation efforts and, last but not least, the wider applications of space traffic control. Regarding the sub-title of the conference, ‘is the space debris problem solvable?’, it would appear from the presentations that while there is the potential for future management of the issue through debris remediation and harmonised mitigation efforts, no comprehensive solutions exist at the time of writing.     

天基激光驱动空间碎片降轨效果仿真研究

在当前天基激光移除碎片方案设计中,通常采用k J级高能激光器、100 m/s大速度增量和简单降轨模型计算移除系统参数,然而k J级天基高能激光器尚未实现。文章基于目前实验室现有的J级激光器水平,参考现阶段碎片移除方案,针对特定区域的目标空间碎片,结合碎片轨道特性信息建立降轨模型,仿真研究目标碎片在低能量天基激光驱动下的运动过程和降轨效果,分析了影响目标碎片降轨效果的因素。对部署在500 km轨道高度的天基平台移除附近碎片的仿真结果表明,速度增量和降轨高度的变化具有累积效应,提高频率、增大有效作用距离等可延长激光烧蚀驱动时间,进而增强碎片降轨效果。分析表明,J级小能量激光器通过长时间的烧蚀,也可有效驱动和移除1~10 cm碎片。     

Investigation of national policy shifts to impact orbital debris environments

Low earth orbit has become increasingly congested as the satellite population has grown over the past few decades, making orbital debris a major concern for the operational stability of space assets. This congestion was highlighted by the collision of the Iridium 33 and Cosmos 2251 satellites in 2009. This paper addresses the current state of orbital debris regulation in the United States and asks what might be done through policy change to mitigate risks in the orbital debris environment. A brief discussion of the nature of orbital debris addresses the major contributing factors including size classes, locations of population concentrations, projected satellite populations, and current challenges presented in using post-mission active debris removal to mitigate orbital debris. An overview of the current orbital debris regulatory structure of the United States reveals the fragmented nature of having six regulating bodies providing varying levels of oversight to their markets. A closer look into the regulatory policy of these agencies shows that, while they all take direction from The U.S. Government Orbital Debris Mitigation Standard Practices, this policy is a guideline with no real penalty for non-compliance. Various policy solutions to the orbital debris problem are presented, ranging from a business as usual approach to a consolidated regulation system which would encourage spacecraft operator compliance. The positive aspects of these options are presented as themes that would comprise an effective policy shift towards successful LEO conservation. Potential economic and physical limitations to this policy approach are also addressed.     

利用等离子体加速器发射超高速 微小空间碎片的研究

文章介绍了国内外微小空间碎片超高速撞击地面模拟实验研究的现状,描述了国内等离子体微小空间碎片加速器的研制进展和初步实验结果,分析了该加速器在空间碎片防护研究工作中的应用。在初步调试阶段,在系统设计满负荷储能6%和35%的条件下,分别将100 ?m和200 ?m的玻璃微粒加速至5.5 km/s和9.3 km/s。利用该加速器可以模拟研究10～1 000 ?m的微小空间碎片对卫星功能材料的撞击损伤特性,可以加速模拟研究卫星关键部件或分系统在大量微小空间碎片撞击下的失效机理和失效模式,为卫星防护微小空间碎片的设计提供技术支持。该加速器还能为国内发展星载空间微小碎片探测仪器的设计和标定提供模拟实验条件。     

天基监测空间碎片有效载荷效能评估方法研究

介绍了用于天基空间碎片监测的主要载荷,包括可见光监测相机、微波雷达和激光雷达。根据评价指标体系,按照评价指标设计的原则,设计出评价指标的体系结构,建立基于AHP（采用层次分析法）的综合指标评估模型。利用评估模型实现对三种监测载荷进行评价分析,选择出效能最优的有效载荷。为天基监测载荷评估提供科学依据与评估方法。     

Debris dispersion effect in N-shape configuration

Spacecraft shields play an important role in shielding against the impact of space debris. Increasing the dispersion degree of the debris produced by the impact of the space debris on the bumper of configuration is able to lower the concentration of debris impacting on the rear plate and thus to reduce the risk of debris perforating the rear plate. In order to improve the dispersion degree, the N-shape configuration is proposed and studied by hypervelocity impact test with the velocity of 4.80 km/s and numerical simulation with the velocities ranging from 3.0 km/s to 7.0 km/s. As a comparison, the distribution of debris impacting on the rear plate is also investigated for the parallel triple-wall configuration with the same areal density. It is found that this degree is increased in the N-shape configuration due to the oblique plate, and therefore the risk of debris perforating the rear plate is reduced compared to the case of parallel triple-wall configuration.     

对欧空局轨道碎片模型的评价

文章评价了颗粒大于1cm的碎片模型,它包含大于10cm的一组粒子和介于1～10cm之间的粒子,它们是由空间暴露模拟得到的。接着讨论了尺寸范围介于0.1～10mm之间的小粒子束流。假定这些粒子主要是由小粒子与卫星碰撞产生的。这种碰撞主要发生在450～500kin的高度范围内(空间站高度),碰撞与否还取决于轨道高度和离心率。     

天基雷达观测空间碎片的研究现状及关键技术分析

文章针对空间碎片观测中尚未得到确切观测数据的危险碎片的观测需求,综合分析了国内外的研究水平和现状,对天基雷达观测的需求和关键技术开展研究,提出了天基空间碎片观测有三个关键技术需要解决,即如何确定雷达工作体制和平台轨道以提高观测效率,如何有效探测尺度只有几个毫米-几个厘米的细小目标,如何对观测到的空间碎片进行分类和精确定轨。     

低地球轨道航天器的轨道碎片环境

文章介绍了一种适用于低地球轨道航天器的轨道碎片环境模型。对建立这个模型的数据源及设计标准进行了详细的叙述。并评价这个数据模型对未来空间环境的预测和测量中的不确定性。     

天基光学传感器的视线测量误差分析

针对天基光学传感器的视线测量误差分析问题,提出一种基于多因素分析的视线测量误差分析方法。利用目标到光学传感器像平面的转换关系,建立目标观测模型。分析视线测量过程中的各种误差源,从理论上推导地惯坐标系下的视线测量误差与卫星轨道误差、卫星姿态误差、传感器指向误差以及像元分辨率的关系。Monte Carlo仿真试验验证了该理论分析方法的有效性,分析结论可以为工程应用提供参考。
     

Will space run out of space? The orbital debris problem and its mitigation

An appraisal of current and future risks from space debris is presented with the aid of calculations carried out by the MASTER model. The efficacy of various technical options -- such as fuel venting, de-orbiting and use of a graveyard orbit -- for counteracting the problem is discussed. The article then focuses on governmental and international cooperative measures and looks at the recent work done by subcommittees of the UN COPUOS.     

Conceptualizing an economically,legally, and politically viable active debris removal option

It has become increasingly clear in recent years that the issue of space debris, particularly in low-Earth orbit, can no longer be ignored or simply mitigated. Orbital debris currently threatens safe space flight for both satellites and humans aboard the International Space Station. Additionally, orbital debris might impact Earth upon re-entry, endangering human lives and damaging the environment with toxic materials. In summary, orbital debris seriously jeopardizes the future not only of human presence in space, but also of human safety on Earth. While international efforts to mitigate the current situation and limit the creation of new debris are useful, recent studies predicting debris evolution have indicated that these will not be enough to ensure humanity?s access to and use of the near-Earth environment in the long-term. Rather, active debris removal (ADR) must be pursued if we are to continue benefiting from and conducting space activities. While the concept of ADR is not new, it has not yet been implemented. This is not just because of the technical feasibility of such a scheme, but also because of the host of economic, legal/regulatory, and political issues associated with debris remediation. The costs of ADR are not insignificant and, in today?s restrictive fiscal climate, are unlikely/to be covered by any single actor. Similarly, ADR concepts bring up many unresolved questions about liability, the protection of proprietary information, safety, and standards. In addition, because of the dual use nature of ADR technologies, any venture will necessarily require political considerations. Despite the many unanswered questions surrounding ADR, it is an endeavor worth pursuing if we are to continue relying on space activities for a variety of critical daily needs and services. Moreover, we cannot ignore the environmental implications that an unsustainable use of space will imply for life on Earth in the long run. This paper aims to explore some of these challenges and propose an economically, politically, and legally viable ADR option. Much like waste management on Earth, cleaning up space junk will likely lie somewhere between a public good and a private sector service. An international, cooperative, public-private partnership concept can address many of these issues and be economically sustainable, while also driving the creation of a proper set of regulations, standards and best practices.     

空间望远镜的热设计和热光学分析综述

文章对国内外典型空间望远镜的热设计进行综述 ,并详细介绍了空间望远镜热光学分析的概念 ,讨论了热设计和热光学分析的关系 ,提出了将卫星热控制技术与光学波像差理论相结合 ,以光学指标作为热设计的最终评价标准 ,并应用于我国空间太阳望远镜(SST)的热设计和热光学分析之中     

空间碎片环境现状与主动移除技术

概述了空间碎片环境现状和对航天活动的影响,讨论了空间碎片主动移除对保持空间碎片环境稳定的必要性。空间碎片研究重心先从防护转向减缓,再转到主动移除,最终是清洁空间。评述了空间碎片主动移除技术现状,指出天基激光主动移除空间碎片技术具有很好的工程应用潜力。     

Debris area distribution of spacecraft under hypervelocity impact

Cross-sectional area is an important parameter for spacecraft breakup debris as it is the directly measured data in space observation. It is significant for observing and analysing the spacecraft breakup event to accurately modelling the area distribution of the breakup debris. In this paper, experimental study has been performed on debris area distribution characteristics of spacecraft under hypervelocity impact. The tests are carried out at the ballistic ranges of CARDC. Aluminium projectiles are launched to normally impact the simulated spacecrafts at about 3.0 km/s. The simulated spacecrafts are made up of aluminium plates, filled with some simulated electronics boxes, each of which was installed with a circuit board. “Soft-catch” devices are used to recover the breakup fragments. The test results show that: 1) the relationship between the cross-sectional area and the characteristic length of debris, which can be obtained in the logarithmic coordinates by linear fitting, represents the debris shape characteristic in a certain extent; 2) the area-to-mass ratios of fragments show normal distributions in the logarithmic coordinates; 3) debris made of different materials can be distinguished by different peaks on the distribution curves; 4) the area-to-mass ratio distributions can be expressed by a linear superimposition of several normal functions which represent the main materials of the spacecraft.