空间机器人主从遥操作的自抗扰控制

目前基于模型的控制方法是空间机器人遥操作控制的主流方法,但该方法不可避免地会引入运动的累积误差,甚至造成控制失稳。针对这一问题,基于自抗扰控制方法为空间机器人主从遥操作设计了一类单关节控制器,并采用计算机仿真方法研究了其基本性能,结果表明所设计的自抗扰控制器能够实现稳定的遥操作控制,且具有良好的抗扰性和鲁棒性。特别是由于自抗扰控制方法不依赖于机器人的数学模型,因此十分适合作为现行基于模型控制的有益补充。     

船载多目标模拟器的构建与应用

船载统一S频段（USB）测控系统是我国航天测控网的重要组成部分,承担着一箭单星或一箭多星的海上测控任务。从航天测量船执行多目标测控任务的特点出发,分析了测量船船载飞行目标模拟器的现状以及对多目标模拟器的需求。提出了在船载USB联试应答机的基础上,通过改造应答机的部分模块,构成多目标模拟器的方法,并成功地在某次实战任务中得到了应用。     

CCSDS航天器在轨接口业务标准化工作综述

介绍了CCSDS(空间数据系统咨询委员会)SOIS(航天器在轨接口业务领域)的各工作组工作现状以及开展的标准建议书情况,分析了已经完成的和正在开展的标准化工作,并研究了该领域的体系结构发展、无线通信标准以及即插即用标准的技术内容。     

航天发射场选址条件与场址勘选方法

航天发射场场址的选择。是发射场规划建设的基础和先决条件,是一门综合性、多学科的复杂系统工程,其选择结果对发射场的综合发射能力、发射场系统和测量控制系统建设难度与投资经费、技术经济效益和可持续发展能力等有着重大影响。本文从我国的国情和航天发射场建设实际情况出发,对发射场选址基本原则、选址条件、勘选程序与基本方法等内容,进行了比较详细的分析论述。     

Planetary penetrators: Their origins,history and future

Penetrators, which emplace scientific instrumentation by high-speed impact into a planetary surface, have been advocated as an alternative to soft-landers for some four decades. However, such vehicles have yet to fly successfully. This paper reviews in detail, the origins of penetrators in the military arena, and the various planetary penetrator mission concepts that have been proposed, built and flown. From the very limited data available, penetrator developments alone (without delivery to the planet) have required ∼$30M: extensive analytical instrumentation may easily double this. Because the success of emplacement and operation depends inevitably on uncontrollable aspects of the target environment, unattractive failure probabilities for individual vehicles must be tolerated that are higher than the typical ‘3-sigma’ (99.5%) values typical for spacecraft. The two pathways to programmatic success, neither of which are likely in an austere financial environment, are a lucky flight as a ‘piggyback’ mission or technology demonstration, or with a substantial and unprecedented investment to launch a scientific (e.g. seismic) network mission with a large number of vehicles such that a number of terrain-induced failures can be tolerated.     

Results of measurements of the response of a delta-doped CCD to neutral and charged particle beams

We report the measurements of the response of a delta-doped Charge Coupled Device (CCD) in imaging mode to beams of charged and neutral particles. That is, the detector imaged the incident beam over its 1024 × 1024 pixels, integrating the number of particles counted in each pixel during the exposure period. In order to count individual particles the exposure time would have had to be reduced considerably compared to the typical ?5 s used in these studies. Our CCD thus operated in a different manner than do conventional particle detectors such as the CEM and MCP that normally are used in a particle counting mode. The measurements were carried out over an energy range from 0.8 to 30 keV. The species investigated include H, H⁺, He⁺, N⁺, N₂⁺, and Ar⁺. The energy and ion mass covered wider ranges than previous measurements for the CCD. The results of these measurements show, as in the case of the previous measurement, for a given ion the CCD response increases with energy and for a given particle energy the response decreases with increasing mass of the particle. These results are in agreement with predictions of the theory of the range of ions in solids. The results also show the possibility for the application of the delta doped CCD as a detector for low energy particle measurements for space plasma physics applications.     

Plants + soil/wetland microbes: Food crop systems that also clean air and water

The limitations that will govern bioregenerative life support applications in space, especially volume and weight, make multi-purpose systems advantageous. This paper outlines two systems which utilize plants and associated microbial communities of root or growth medium to both produce food crops and clean air and water. Underlying these approaches are the large numbers and metabolic diversity of microbes associated with roots and found in either soil or other suitable growth media. Biogeochemical cycles have microbial links and the ability of microbes to metabolize virtually all trace gases, whether of technogenic or biogenic origin, has long been established. Wetland plants and the rootzone microbes of wetland soils/media also been extensively researched for their ability to purify wastewaters of a great number of potential water pollutants, from nutrients like N and P, to heavy metals and a range of complex industrial pollutants. There is a growing body of research on the ability of higher plants to purify air and water. Associated benefits of these approaches is that by utilizing natural ecological processes, the cleansing of air and water can be done with little or no energy inputs. Soil and rootzone microorganisms respond to changing pollutant types by an increase of the types of organisms with the capacity to use these compounds. Thus living systems have an adaptive capacity as long as the starting populations are sufficiently diverse. Tightly sealed environments, from office buildings to spacecraft, can have hundreds or even thousands of potential air pollutants, depending on the materials and equipment enclosed. Human waste products carry a plethora of microbes which are readily used in the process of converting its organic load to forms that can be utilized by green plants. Having endogenous means of responding to changing air and water quality conditions represents safety factors as these systems operate without the need for human intervention. We review this research and the ability of systems using these mechanisms to also produce food or other useful crops. Concerns about possible pathogens in soils and wastewater are discussed along with some methods to prevent contact, disease transmission and to pre-screen and decrease risks. The psychological benefits of having systems utilizing green plants are becoming more widely recognized. Some recent applications extending the benefits of plants and microbes to solve new environmental problems are presented. For space applications, we discuss the use of in situ space resources and ways of making these systems compact and light-weight.     

Improved orbit predictions using two-line elements

The density of orbital space debris constitutes an increasing environmental challenge. There are two ways to alleviate the problem: debris mitigation and debris removal. This paper addresses collision avoidance, a key aspect of debris mitigation. We describe a method that contributes to achieving a requisite increase in orbit prediction accuracy for objects in the publicly available two-line element (TLE) catalog. Batch least-squares differential correction is applied to the TLEs. Using a high-precision numerical propagator, we fit an orbit to state vectors derived from successive TLEs. We then propagate the fitted orbit further forward in time. These predictions are validated against precision ephemeris data derived from the international laser ranging service (ILRS) for several satellites, including objects in the congested sun-synchronous orbital region. The method leads to a predicted range error that increases at a typical rate of 100 m per day, approximately a 10-fold improvement over individual TLE’s propagated with their associated analytic propagator (SGP4). Corresponding improvements for debris trajectories could potentially provide conjunction analysis sufficiently accurate for an operationally viable collision avoidance system based on TLEs only.     

Charged particles on the Earth–Jupiter–Europa spacecraft trajectory

Charged particle fluxes on the trajectory of future Russian space research mission to Jupiter and its satellite Europa are investigated. The existing experimental data and models of Jupiter’s main magnetic field and radiation belts are summarized. Preliminary results of computations of energetic particle fluxes and radiation doses for each stage of the flight are given. Special attention is paid to estimation of radiation conditions in Europa’s orbit and on its surface; influence of the satellite on spatial distribution of the fluxes of charged particles of various energies is studied.