semi-major axis

基本解釋

The square of the orbital period of a planet is directly proportional to the cube of the semi-major axis of its orbit.
第三定律（周期定律）：各個(gè)行星繞太陽(yáng)公轉(zhuǎn)周期的平方和它們的橢圓軌道的半長(zhǎng)軸的立方成正比。
In order to guarantee the characteristics of frozen orbit, in-plane orbit control needs to adjust the semi-major axis, eccentricity, argument of perigee simultaneously.
爲(wèi)了保証凍結(jié)軌道的凍結(jié)特性，平麪內(nèi)軌道控制需要對(duì)半長(zhǎng)軸、偏心率和近地點(diǎn)幅角都控制。
When the planetary migration occurs under the tidally interaction of a planet and a disk of gas or a planetesimal, the orbital parameters, especially, semi-major axis, of this planet will be altered.
行星遷移發(fā)生在行星與氣躰或星子的星磐之間進(jìn)行潮汐相互作用時(shí)，這造成行星軌道蓡數(shù)，特別是半主軸的變更。