My nine-year-old son has never known a time without humans living in space. In fact, my son has never known a time when the benefits of space exploration haven’t had a direct impact on the quality of his life here on Earth.

never和without在一起构成双重否定。明白是双重否定后，句义就容易理解多了。(个人意见，仅供参考)

忽然有一种被世界抛弃了的感觉