China's Tiangong-1 (or Heavenly Palace) space station made a fiery return to Earth, crashing into the South Pacific on April 1 and ending its 6½-year sojourn through space. The mission was a milestone in China's space program and a stepping stone in its off-world ambitions. Tiangong's end is also an important reminder of the need for an international regime to deal with space debris. The vital importance of outer space to modern economies demands cooperation among governments here on Earth.

The 9.4-ton spacecraft, about 12 meters long with a volume of 15 cubic meters, was launched Sept. 29, 2011, into an orbit about 350 km above Earth. Its main purpose was to help China develop and polish the skills and technologies necessary to sustain an ambitious space program. An unmanned spacecraft docked with the space station in November 2011, less than two months after it was launched. In June 2012, a crew of three taikonauts — Chinese astronauts — traveled to the station for two weeks; a second crewed mission rendezvoused for another two-week stay in June 2013.

Tiangong-1's mission was a success. Its anticipated life span was just two years, but it continued to transmit data to Earth until March 2016, when it went silent for reasons not yet disclosed by the Chinese government. The space station's orbit gradually decayed — as anticipated — until its re-entry earlier this week.