The moon at all times lies somewhere on that small ellipse which moves along with the earth in its orbit 月亮永远处于这个小小的椭圆上，而这个椭圆随地球的轨道运动而移动。
When people run around and around in circles we say they are crazy . when planets do it we say they are orbiting 人绕着圈子没完没了地跑的时候，我们说他抓狂。行星这样做时，我们管这叫做绕轨道运动。
In the first part , the biology study evolvement of molecular motor are introduced , including their categories , structure features and motion properties 第一部分介绍了分子马达的生物学研究进展，包括马达的种类、结构特征和沿轨道运动的性质。
The body travels in an ellipse , the fixed point being at on focus . the speed is greatest when body is near the focus , less when it is farther away 物体沿着固定点在一个焦点上的椭圆轨道运动。当运动物体靠近这一焦点时其速度最大，而当它远离时则速度变小。
Hence , for the most part , observations of accretion disks and orbital motions merely indicate that there is a compact object of a certain mass , and says very little about the nature of that object 因此大体上，增大圆盘片和轨道运动的观察只指示有某个质量紧凑的物体,而且有关那个物体的性质说得非常少。
Orbiting satellites were better at spying on enemies than wayward reconnaissance drones , and rockets destroyed targets more reliably than temperamental flying bombs did 按轨道运动的卫星比难以驾驭且以监控为主的无人驾驶飞机更好地侦查敌情，而且相对于我行我素的自动导航导弹而言，用火箭来毁灭目标更具可靠性。
Galileo was further hobbled by an erratic tape recorder . after the craft began orbiting jupiter in 1995 , repeated zappings from the planet ' s intense radiation belts damaged other instruments 伽利略号又被一个漂浮在太空的磁带录音机所拖累。在飞船1995年后围绕木星轨道运动时，从行星的强辐射带发射的循坏的跳过节目的辐射损坏了其他一些仪器。
If einstein is right , scientists say , the satellite should detect that small bits of time and space are actually missing from each orbit , something indiscernible to orbiting astronauts but measurable nonetheless 科学家说:如果爱因斯坦是对的,那么这个人造卫星应该能探测到少量的时间和空间确实从每个轨道上丢失了,这些丢失的时间和空间虽然随轨道运动的宇航员看不到,但确实能测量
Since its launch in 1990 the hubble space telescope has captured beautiful images of the universe , such as the birth of stars in stellar nurseries , while conducting rigorous science , such as the recent detection of planets orbiting stars near the centre of the milky way 自从1990年发射后，哈勃望远镜已经捕捉到很多宇宙的美丽景象，比如在星的托儿所恒星的诞生，还有最近对围绕银河中心附近的恒星做轨道运动的星球的侦测。
Case 1 : when there is no relative measurement , each satellite uses its own on - board attitude sensors to determine its attitude , and exchange the information through the communication link between formation satellites , and then the relative attitude is determined through simple mathematical operation . case 2 : based on the range measurements of gps like sensors , using two - point measurement of the relative orbit state to establish relative orbit and attitude kinematics and measuring equations . and state estimation is achieved through the extended kalman filter technology and unscented kalman filter technology , respectively 方案一,在星间无相对测量时,由卫星自身携带的姿态敏感器实现单星高精度姿态确定,利用星间通信链路进行信息交互,通过简单的数学计算获得星间相对姿态;方案二,利用类gps相对测量,建立了编队卫星相对轨道运动和相对姿态运动模型及相对距离测量方程,推导了两点相对轨道运动模型,设计了扩展卡尔曼滤波器及uscented卡尔曼滤波器,对相对位置、速度和姿态进行估计。
