火星太阳电池翼除尘方法综述

“萤火一号”火星探测器即将发射升空,标志着我国火星探测计划实施的开始。然而,火星尘埃在范德华力和静电力的作用下积聚在太阳电池翼的表面,使其转换效率下降,影响火星探测器的寿命。因此,开展火星太阳电池翼除尘技术的研究是非常有意义的。文章主要介绍了火星太阳电池翼的除尘方法,特别是目前最受关注的电帘除尘方法,并对其基本结构、除尘原理、除尘效率和透光性做了详细的描述,对开展火星太阳电池翼除尘技术的研究具有一定的参考作用。     

Practical guidelines for electro-dynamic tethers to survive from orbital debris impacts

Japan Aerospace Exploration Agency (JAXA) has proposed an active debris removal using electro-dynamic tether to reduce large space debris in the low-Earth orbit. However, a tether strand is thin but long enough to have a large area so that it is vulnerable to small particles. This vulnerability might be the weakest point of a tether system against orbital debris. In order to overcome this weakest point, a double tether system, in which two tether strands are tied together at even intervals to form equally spaced loops, has been suggested as one of the promising candidates. This paper provides a mathematical approach to estimate the survival probability of a double tether system and then apply the approach to evaluate the mission success rate of the active debris removal using electro-dynamic tether that JAXA has proposed. It can be concluded the countermeasure to get enough success rate can be obtained. The result is simulated for Advanced Earth Observing Satellite II (ADEOS-II) re-entry from 800 km sun synchronized orbit to atmosphere. The simulation shows that mission success rate over 90% can be obtained with number of loops over 1000 and 10 mm clearance between two strands.     

Fuzzy multi-criteria decision-making approach to prioritization of space debris for removal

As private companies and government space agencies begin to seriously consider the task of active space debris removal, it is becoming increasingly more important to determine the highest priority objects to deorbit. This work sets forth an approach for prioritization of space debris through the utilization of Multi-Criteria Decision-Making methodologies and fuzzy logic, as well as both quantitative and qualitative criteria. The proposed debris prioritization approach considers various criteria including the orbit, size, mass, pairwise and total collision probabilities, and decay timeframe of each debris object. The means of assigning attributes to each assessment criterion is discussed in detail. To determine the weighting scheme for the criteria, a questionnaire was prepared and shared with experts in the field of space situational awareness. The work examines over two thousand critical debris objects selected from the existing debris catalog with respect to these criteria. The quantified attributes for each debris object are then aggregated through the fuzzy versions of the Analytic Hierarchy Process and the Technique for Order Preference by Similarity to Ideal Solution. The results of the analysis identify high-priority debris objects for removal from Earth-bound orbits.     

忆阻细胞神经网络及图像去噪和边缘提取中的应用

结合忆阻器的记忆特征和细胞神经网络高效并行处理能力,将忆阻器作为可编程连接权值,提出了一种具有忆阻器特性的细胞神经网络.计算机仿真验证了提出的忆阻细胞神经网络用于图像去噪和边缘提取的有效性.     

中小企业质量管理体系建立方案初探

目的 中小企业为确保产品质量，就必须建立起科学的质量管理体系。方法 将影响质量管理的各个要素和工作流程通过科学、严密的程序加以控制，持续改进。结果 通过各种控制增强全员的质量意识，品牌意识。结论 产品质量维系着企业的生命，只有建立起科学的质量管理体系，企业才能发展和壮大。     

产品数字化设计中的标准化工作

介绍洪都集团在产品数字化设计中开展基础标准化工作情况,说明基础标准化工作的重要性,提出了今后标准化工作目标。     

Approaching control for tethered space robot based on disturbance observer using super twisting law

Approaching control is a key mission for the tethered space robot to perform the task of removing space debris. But the uncertainties of the TSR such as the change of model parameter have an important effect on the approaching mission. Considering the space tether and the attitude of the gripper, the dynamic model of the TSR is derived using Lagrange method. Then a disturbance observer is designed to estimate the uncertainty based on STW control method. Using the disturbance observer, a controller is designed, and the performance is compared with the dynamic inverse controller which turns out that the proposed controller performs better. Numerical simulation validates the feasibility of the proposed controller on the position and attitude tracking of the TSR.     

A deorbiter CubeSat for active orbital debris removal

This paper introduces a mission concept for active removal of orbital debris based on the utilization of the CubeSat form factor. The CubeSat is deployed from a carrier spacecraft, known as a mothership, and is equipped with orbital and attitude control actuators to attach to the target debris, stabilize its attitude, and subsequently move the debris to a lower orbit where atmospheric drag is high enough for the bodies to burn up. The mass and orbit altitude of debris objects that are within the realms of the CubeSat’s propulsion capabilities are identified. The attitude control schemes for the detumbling and deorbiting phases of the mission are specified. The objective of the deorbiting maneuver is to decrease the semi-major axis of the debris orbit, at the fastest rate, from its initial value to a final value of about 6471?km (i.e., 100?km above Earth considering a circular orbit) via a continuous low-thrust orbital transfer. Two case studies are investigated to verify the performance of the deorbiter CubeSat during the detumbling and deorbiting phases of the mission. The baseline target debris used in the study are the decommissioned KOMPSAT-1 satellite and the Pegasus rocket body. The results show that the deorbiting times for the target debris are reduced significantly, from several decades to one or two years.     

Feasibility analysis of LEO and GEO large space debris de/re-orbiting taking into account launch mass of spacecraft-collector and its configuration layout

Analysis of the efficiency of two basic strategies for de/re-orbiting large space debris objects to disposal orbits (DO) is given. Large objects in LEO are classified into groups with similar orbital inclinations and comprise primarily last stages of launch vehicles, in GEO vicinity the paper studies upper stages. Under the first de/re-orbiting variant, it is assumed a spacecraft-collector is equipped with several thruster de/re-orbiting kits (TDKs); one of them can be fixed on an object and is capable of de/re-orbiting an object to a DO independently of the collector. In the second variant, a collector operates as a space tug: transfers objects to a DO and then returns to the next objects in line. The authors study possible configuration layouts of collectors in LEO and near GEO. The available analogous projects are analyzed. The efficiency of both de/re-orbiting variants can be properly compared using the estimations of collector's dry mass and having at one's disposal the parameters of the maneuvers required for transfers between all objects in the group. As reasonable criteria of effectiveness, one can consider (separately or jointly) the launch mass of an equipped collector, its ΔV budget, and the required number of such active spacecraft. Two de/re-orbiting variants are compared in terms of these criteria via mass-energy diagrams constructed for each group of objects in both altitude regions. Analysis of these diagrams shows that low Earth orbits can be more efficiently cleaned under the first de-orbiting variant by using a two-stage space system consisting of an active spacecraft carrying TDKs. For GEO, it is expedient to choose the second re-orbiting variant using a single-stage spacecraft. Our analysis shows that LEO cleaning is an order of magnitude more expensive than that for GEO, hence the problem of LEO population should be given increased attention.     

Exploration life support technology challenges for the Crew Exploration Vehicle and future human missions

As NASA implements the U.S. Space Exploration Policy, life support systems must be provided for an expanding sequence of exploration missions. NASA has implemented effective life support for Apollo, the Space Shuttle, and the International Space Station (ISS) and continues to develop advanced systems. This paper provides an overview of life support requirements, previously implemented systems, and new technologies being developed by the Exploration Life Support Project for the Orion Crew Exploration Vehicle (CEV) and Lunar Outpost and future Mars missions. The two contrasting practical approaches to providing space life support are (1) open loop direct supply of atmosphere, water, and food, and (2) physicochemical regeneration of air and water with direct supply of food. Open loop direct supply of air and water is cost effective for short missions, but recycling oxygen and water saves costly launch mass on longer missions. Because of the short CEV mission durations, the CEV life support system will be open loop as in Apollo and Space Shuttle. New life support technologies for CEV that address identified shortcomings of existing systems are discussed. Because both ISS and Lunar Outpost have a planned 10-year operational life, the Lunar Outpost life support system should be regenerative like that for ISS and it could utilize technologies similar to ISS. The Lunar Outpost life support system, however, should be extensively redesigned to reduce mass, power, and volume, to improve reliability and incorporate lessons learned, and to take advantage of technology advances over the last 20 years. The Lunar Outpost design could also take advantage of partial gravity and lunar resources.