NASA在1962年到1971年间发射了被称为“轨道太阳观测台”的一系列共8个轨道观测卫星。

NASA launched a series of eight orbiting observatories known as the orbiting Solar Observatory between 1962 and 1971.

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与之对应，直线段的钢轨通常打磨成与车轮有几点接触的形状，车轮与轨道之间是非共形接触，从而减少轮对不正常的摆动。

Tangent track, on the other hand, may be ground to several contact points to promote non-conformal contact and thus reduce wheelset hunting.

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美国宇航员杰夫·威廉姆斯成了美国在轨道内最长时间纪录的保持者——算上这次任务，他一共参加了四次不同的任务，在太空中待了534天。

American astronaut Jeff Williams became the U. s. record-holder for most time spent in orbit after this mission brought him up to 534 days spent in space across four separate missions.

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