And considering the comet's nearly parabolic orbit, experts said, that first visit may have been its last.
专家们表示，鉴于其近抛物形轨道，鹿林彗星的第一次造访也可能是最后一次。
After the first stage burns out it falls back to earth along a parabolic path while the engines of the second stage fire to thrust the rocket into an earth orbit.
当第一级烧毁后，沿抛物线的轨道落到地球，而第二级的发动机点火把火箭发射到地球轨道。
The radiant cooler used in the sun synchronous orbit is always designed two stages with a W-shaped parabolic reflector.
在太阳同步轨道卫星上应用的辐射制冷器都采用两级抛物面w型的结构形式。
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