摘要
激光天文动力学空间计划概念是一个多目标的空间实验,使用在太阳轨道上无拖曳航天器和地日间L1(L2)点附近无拖曳航天器/地球卫星/地面站,以激光干涉测距的方法相互测距,精确地探讨天文动力学,检测相对论与时空基本定律,改进探测引力波的灵敏度以及更准确地测定太阳、行星和小行星的参数;其精确度将比现在提高3到5个数量级。一个简单的方案是使用一个航天器和地面站相互激光测距,是激光天文动力学空间计划的第一步,称为单航天器激光天文动力学空间计划ASTROD Ⅰ,可改进相对论检测3个数量级与太阳系参数1-3个数量级。我们要求ASTROD Ⅰ加速度计的加速度噪声在0.1mHz时小于10^(-13)ms^(-2)Hz^(-1/2)。要设计ASTROD Ⅰ的有效载核和航天器,对干扰和噪声要求的研究是不可避免的。在此论文中,我们估计可能的加速度干扰和讨论对ASTROD Ⅰ无拖曳航天系统的要求。我们的讨论包括保证质量的磁化率可接受的大小、保证质量和航天器温度控制的可接受的大小、保证质量和航天器耦合可接受的大小、对加速度计读出灵敏度和航天器控制环增益的要求等。和LISA(欧美的引力波空间任务,计划于2014年发射)相比,ASTROD Ⅰ的要求可以相对的宽松。这将使ASTROD Ⅰ为了满足无拖曳航天的要求所需的技术开发较易进行。
ASTROD (Astrodynamical Space Test of Relativity using Optical Devices) has been proposed as a multipurpose space-borne experiment, which aims at testing relativistic gravity, measuring the solar-system parameters with a high precision and detecting gravitational waves from massive black holes and galactic binary stars. A simple version of ASTROD, ASTROD I, has been proposed as the first step to ASTROD. The accelerometer of ASTROD I is required to satisfy the acceleration noise level better than 10^(-13) ms^(-2) Hz^(-1/2) at 0.1 mHz. To design the experimental facilities for ASTROD I, investigation of possible disturbances is inevitable. In this paper, we focus on the disturbances related to the ASTROD I accelerometer. We estimate the possible acceleration disturbances and discuss the drag -free requirements for the accelerometer and experimental facilities. The discussion includes, for instance, the acceptable level of magnetic susceptibility of the proof-mass and the required level of temperature control for the proof -mass and the spacecraft. Also, we compare the requirements with another space - borne gravitational experiment, LISA (Laser Interferometer Space Antenna).
