Helium is used to pressurize tanks and help push fuel into the engines. Without proper helium flow, the rocket cannot safely fly. Because the upper stage is hard to reach at the launchpad, NASA rolled the stacked rocket back into the Vehicle Assembly Building, the sky-scraping hangar where it was originally put together.
; RETF (protected mode) — execution flows DOWN this listing
。关于这个话题，搜狗输入法下载提供了深入分析
// 易错点3：跨度计算公式写反（stack[...]-i）→ 结果为负数，完全错误
NZDT — 3 a.m. (Feb. 28)