The most feature of the orbits of Near Earth Asteroids(NEAs) is that the semi major axes of the orbits are nearly equal to that of the Earth or the perihelia distances are approximate to or even less than the mean distance between the Sun and the Earth,thus they could move into inside of the Earth s orbit,so that th.
近地小行星轨道的最大特点是其轨道半长径与地球轨道半长径相近 ,或近日距离接近甚至小于日地平均距离 ,其运动可深入到地球轨道的内部 ,这将导致该类小行星与地球 (还有金星、火星等 )十分靠近甚至发生碰撞 。
The unscented Kalman filter(UKF) was applied for geomagnetism autonomous navigation in LEO satellite in this paper when the magnitude of the geomagnetic field vector was served as observed value.
以地磁场强度矢量的模为观测量,将Unscented卡尔曼滤波(UKF)用于近地卫星的磁测自主导航。
The process in which the LEO satellite deviates from the nominal orbit can be considered the relative motion between two satellites, i.
近地卫星偏离标称轨道的过程可以表示为该卫星和一个在标称轨迹上运行的"虚"卫星的相对运动,服从Hill方程。
Near Earth Asteroid Rendezvous spacecraft
近地小行星会合航天器
The NEAR-Shoemaker probe touched down after studying the asteroid Eros for the past year.
“近地小行星约会”外太空探测器在对厄罗斯小行星研究了一年后才进行着陆。
Eros is one of the planetoids which passes near the earth every now and then.
爱神星是一个时常靠近地球的小行星。
Mars and Jupiter are the closest in of the superior planets.
火星和木星是最靠近地球轨道外侧的行星。
Strictly speaking, the earth is a nearly spherical planet.
严格地讲，地球是一个近似球体的行星，
The Earth is a nearly spherical planet.
地球是一个近似球体的行星。
The Approximate Formular about The Speed of The Artificial Satellite Moving at Some Spot;
关于人造卫星绕地球运行的近似公式
The Characteristics of Near Asteroid Orbital Dynamics and its Implication to Mission Analysis
飞行器近小行星轨道动力学的特点及研究意义
From the astronomical point of view, this asteroid was very close to the Earth because the moon is only 402,000 kilometers away from the Earth.
从天文学的角度来说这颗小行星是非常靠近地球的，因为月亮距离地球40万2000公里。
Study of the Maneuver Flying Guidance Techniques for Small Satellite Autonomous Proximity Operations;
小卫星自主临近作业机动飞行制导技术研究
Relativity research on near-ground and satellite remote sensing reflectance of wheat stripe rust
小麦条锈病卫星与近地光谱反射率的比较
she works nearby; the planets orbiting nearby are Venus and Mars.
她在附近工作；在附近运行的行星是金星和火星。
one of the largest asteroids being studied.
比如，NEAR（近地行星聚集点）中一艘监视Eros的太空船，
Alternatively, if the star were small, the life-supporting planet would have to have a close orbit round it,
反之，如果恒星很小，维持生命的行星就要在离恒星很近的轨道上运行，
Mercury, less than half as far from the sun as the Earth, is the planet closest to the sun.
水星是离太阳最近的行星，它离太阳还不到地球离太阳的一半。
To put it simply, the earth is a small planet.
简而言之，地球是个小行星。
Oh, thank goodness we're coming out of the asteroid field.
谢天谢地我们总算离开小行星群了
Gargantuan asteroid to pass near Earth this fall.
大量小行星今秋将与地球错身而过。