小行星Icarus激光测距空间任务科学价值的研究  

A Study of the Scientific Value of the Asteroid Icarus Laser Ranging

作　　者：罗永杰[1,2] 夏炎[1,2] 李广宇[1] 

机构地区：[1]中国科学院紫金山天文台,南京210008 [2]中国科学院研究生院,北京100049

出　　处：《天文学报》2009年第2期197-205,共9页Acta Astronomica Sinica

基　　金：国家自然科学基金(10503013)资助项目

摘　　要：小行星Icarus激光测距空间任务是在第1566号小行星上放置激光反射器、定时器并与地面站之间进行激光干涉测距,对PPN参数γ和β、太阳四极矩J_2、万有引力常数的时间变化率G/G和太阳系天体的质心引力常数进行精确测量.随着激光技术的发展,10ps(用测距量表示是3mm)的计时精度是可以实现的.2015年Icarus与地球接近,为Icarus着陆器提供了良好的发射窗口.本文采用PMOE 2003行星历表框架,从2015年9月25日起,对地面站和小行星之间的激光测距进行了为期800天的模拟,应用Kalman滤波方法,得到18个参数的不确定度,其中γ、β、J_2和■/G的不确定度分别为7.8×10^(-8)、9.0×10^(-7)、9.8×10^(-11)和7.0×10^(-15)yr^(-1),均高于现有实验的精度1—3个数量级.模拟结果表明,这个空间任务对相对论的检验、太阳系基本参数的测定、以及时空基本定律的检验等都有重要的科学意义.The asteroid Icarus laser ranging mission includes to place a set of laser reflector, timer onto Icarus and to range between the Icarus and the Earth ground stations, which will precisely measure PPN parameters γ and β, the solar quadruple moment J2, the temporal variation of the gravitational constant GIG , and the barycentric constants of the solar-system bodies. With the advances in laser technology, a timing accuracy of 10 picoseconds （3mm in terms of ranging） can be realized. The Icarus will approach to Earth in the year 2015, which provides a good launch window for an Icarus lander. There is a simulation of the laser ranging between the ground station and the Icarus for a period of 800 days starting from September 25, 2015 by using PMOE 2003 planetary ephemeris framework, and obtained the uncertainties of 18 parameters after making a fit of them with Kalman filter method. From this simulation, the uncertainties for γ, β, J2 and GIG are determined to be 7.8×10^-8、9.0×10^-7、9.8×10^-11 and 7.0×10^-15yr^-1 respectively, which are 1--3 orders of magnitude more accurate than the results from the empirical experiments to date. The result of this simulation also makes much sense for the test of relativity, the measurement of the solar-system fundamental parameters, and the test of fundamental laws of space and time.

关 键 词：天体测量学 激光测距 小行星 个别 相对论 

分 类 号：P124[天文地球—天体测量]