在轨建造中的关键力学问题

The key mechanical problems of on-orbit construction

在轨建造是指在空间轨道或者地外天体上就地取材或者利用携带的材料、组件通过加工、组装形成航天器及其部组件的过程.由于无需经历发射段苛刻的力学环境,不受运载火箭整流罩空间的限制,因此,在轨建造能够有效降低航天器结构的重量,实现百米甚至千米级空间设施的建设.本文首先分析了在轨建造的技术优势和航天领域的工程需求.其次,分析了空间微重力、高真空和极端温度环境下加工过程中材料的受力和运动行为,以及对制件特性的影响;再次,分析了空间超大型结构在轨建造全过程的激励和扰动源、动力学分析与控制的力学问题;最后,梳理了面向在轨建造的空间大型结构设计的力学约束,给出多级空间桁架结构在轨建造的优化设计模型.

On-orbit construction is an space mission to construct spacecraft and modules on spatial orbits or objects outside the Earth,which would be manufactured and assembled with the local or carry-on materials.Since it is not necessary to undergo the severe mechanical environment during the rocket launching and not constrained by the limit room in rocket dome,on-orbit construction can reduce the weight of the spacecraft effectively and complete the construction of ultra- large space facility in hundreds or even thousands meters.It shows the tremendous potential for human space exploration.However,some challenging mechanical factors need to be considered for this exciting plan.In this paper some key mechanical problems were discussed about the concept and process of on-orbit construction with the complete concept on demand,material requirements,space environment,dynamics,and mechanical constrains.The technical advantages and the practical demand are introduced for the on-orbit construction in the aerospace engineering.And the methodology on material processing were proposed.Some unique chareacteristics of space enviroment were considered, e.g.microgravity,high vacuum and extrame temperature conditions,along with the change on physical properties.The material property is fundamental and challenging for the construction.Furthermore,the dynamic analysis and control strategy were analyzed in all fabricating process for ultra-lage structures.The possilbe exciters and source of fluctuation were discussed.At last,the mechanical constrains were clarified for large space sturcture in on-obrit construction.And a two steps optimization model was defined for structure topology and construction path.Some suggestions were given on the key mechanical problems in the field of on-orbit construction.