A Long March 5B rocket lifts off with the Tianhe space station module. Credit: Xinhua
For the second time in a year, a large spent Chinese rocket stage intentionally left in orbit is heading for an unguided plunge back into Earth’s atmosphere Saturday or Sunday somewhere between 41.5 degrees north and south latitude.
The heavy-lift Long March 5B rocket stage took off April 28 with the Tianhe core module for China’s space station. The Long March 5B — one of the most powerful rockets in the world — tracked downrange to the southeast from the Wenchang launch base on Hainan Island, China’s southernmost province.
The launcher shed its four strap-on boosters about three minutes into the mission, but the two engines on the Long March 5B’s core stage continued firing for about eight minutes, doing all the work to place the 54.4-foot (16.6-meter) Tianhe space station module into orbit.
Most rockets have an upper stage to finish the job of deploying payloads into orbit. On those launchers, the first stage does not attain enough velocity to orbit the Earth. SpaceX recovers its first stages for reuse, while other launchers have booster stages that fall back to the ground hundreds of ...