* @param arr 待排序数组
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The idea is to gain valuable near-term flight experience before attempting a moon landing with astronauts on board. With Artemis III under its belt, NASA hopes to launch two moon landing missions in 2028, Artemis IV and V, using one or both landers, and to continue with one moonshot per year thereafter.
Author(s): Marco Seiz, Tomohiro Takaki