On May 8, debris from a Chinese Long March 5B rocket landed in the Indian Ocean west of the Maldives. The rocket was launched on April 29 to carry the Tiangong space station’s core capsule into orbit. There are no reports that any of the debris fell on land.
NASA criticized China for the rocket’s uncontrolled and unpredictable reentry, claiming the country’s space program was “failing to meet responsible standards regarding their space debris.”
In response, Chinese Foreign Ministry spokesperson Hua Chunying tweeted:
“There's no surface damage reported for #China's rocket. Burning rocket remnants of #US rocket crashing on a farm in March were described by some US media as ‘leaving comet-like trails’.”
A follow-up tweet read:
“But when it comes to #China, the tune is completely different. Some people may be forgetful, but the Internet has a long memory. No #DoubleStandard.”
Those tweets are misleading.
While it is true that no debris from the Long March rocket fell on land, it well could have happened due to the rocket’s design.
Normally, booster rockets are constructed to fall to Earth quickly, on a predicted path over the ocean, or are aimed at a “graveyard” or disposal orbit, where they may remain for decades. In contrast to rocket designs used by other countries, however, the Long March 5B was designed to remain in a low and uncontrolled orbit.
The Long March 5B consists of a core unit and four booster rockets. After the April 29 launch successfully put the Tianhe space station capsule into orbit, the main rocket body went out of control. Weighing in at some 18 metric tons, this was one of the largest man-made objects ever to have fallen out of orbit to Earth.
But this wasn’t China’s first time: There were two similar incidents in 2018 and 2020. In 2018, part of the Tiangong 1 station's prototype lab fell uncontrolled to Earth and landed in the Pacific Ocean. The 2020 incident was more serious, when debris from the main section of another Long March rocket fell on some inhabited areas of the Ivory Coast. Property damage was reported but no casualties.
The Chinese Foreign Ministry spokesperson’s comparison to a U.S. rocket referred to a SpaceX Falcon 9 that burned up over the states of Oregon and Washington while re-entering Earth’s atmosphere in March.
The Falcon 9 rocket's second stage, which is much smaller than the Long March 5B core rocket, is designed to make a controlled deorbit and burn up without presenting a danger. The controlled re-entry failed due to a technical problem in March, however, and a piece of the Falcon 9 was found on the property of a Washington farmer.
Chinese officials have asserted that it is normal practice to let rockets burn up in the atmosphere, but the comparison is a false equivalence, according to a report in Space News. Normally, it is the smaller, upper stages of rockets that are allowed to burn up on re-entry after performing a controlled deorbit burn, while the larger first stage does not reach orbit and falls back to Earth soon after launch.
Space News reported:
Unusually for a first stage the rocket body had entered and remained in orbit following launch, and would become one of the largest instances of uncontrolled reentry of a spacecraft in decades. While the 22.5-ton Tianhe core module used its own propulsion to raise its orbit, the orbit of the first stage began to decay due to atmospheric drag.
The story further cited a May 7 news conference and comments by Foreign Ministry spokesman Wang Wenbin:
Wang stated that it was 'common practice across the world for upper stages of rockets to burn up while reentering the atmosphere,' either intentionally or otherwise obfuscating between first and upper stages. In the case of the Long March 5B core stage it is, exceptionally, both.