An out-of-control piece of a Chinese rocket booster crash-landed in the Pacific Ocean Friday morning — scattering tons of metal across the water’s surface as the world watched nervously, according to space officials. The 23-ton hunk of space junk re-entered the atmosphere in a south-central section of the ocean just after 6 a.m., United States Space Command said in a tweet. China left it to luck where the charred spacecraft stage would fall after it blasted off Monday — the third time in two years the country had an uncontrolled rocket reentry, experts and officials said. “The thing I want…