China’s space agency successfully launched a Long March 5B rocket on Sunday, delivering a new module to its fledgling space station. However, as with previous launches, the rocket’s core stage remained in orbit and is now set for an uncontrolled re-entry.
The Long March 5B took off from the Wenchang Space Launch Center in Hainan on Sunday, June 24, at 2:22 pm Beijing Time. Packed atop the rocket was the 22-ton Wentian laboratory, which arrived at China’s Tiangong space station 13 hours later, according to the state-owned China Daily. Chen Dong, Liu Yang, and Cai Xuzh were waiting for the 18-meter module, which made them the first astronauts in China’s space history in assisting in an orbital docking. Wentian docked with the front port of the Tianhe core module, creating a T-shaped space station.
Instead of celebrating this achievement, however, we are forced to wonder when the 21-metric-ton core stage will return to the atmosphere and where it will crash. Such is the pattern with Long March 5B launches, as two previous missions resulted in chaotic reentries (during controlled reentries, rocket stages are brought down with engines restarted, allowing launch providers to move the body away from the rocket from populated areas, usually into the ocean). In May 2020, debris from a runaway core stage fell on an inhabited area along the west coast of Africa, while a rocket launched in April 2021 crashed in the indian ocean near the Maldives.
The chances of rocket debris falling on your home are exceptionally low, but the risk to human life and property exists. According to research published earlier this month, the chance that someone will be killed or injured by the fall of rocket parts will increase to 10% in the next decade. It has been rebuked to China for not taking better care of its incoming rockets, but the stage appears to be set, once again, for a recurrence of the previous two episodes.
And, in fact, the US Space Command cataloged two objects from Sunday’s launch, one of them Wentier and the other the discarded core stage. Astronomer Jonathan McDowell of the Harvard-Smithsonian Center for Astrophysics expects the stage to re-enter Earth’s atmosphere within a week or so.
“Unfortunately, we can’t predict when or where,” he explained to me in an email. “Such a large rocket stage should not be left in orbit to make an uncontrolled re-entry; the risk to the public is not huge, but it is bigger than it should be.”
During a live broadcast of the launch on the China Global Television Network, Xu Yangson, director general of the Asia-Pacific Space Cooperation Organization, said China took action this time to make sure that the center stage will return in a controlled manner, but it didn’t. When asked about Xu’s comment, McDowell said, “I think he is misinformed.” McDowell is likely right, as the core stage of Long March 5B would require a significant upgrade or overhaul to suddenly have controlled re-entry capability.
As for the Wentien module, it will now be used to support a range of scientific experiments ranging from studies of microgravity and the effects of space radiation to experiments studying the growth of plants, insects, small mammals and microbes. A third module, called Mengtian, is scheduled to launch in October. China intends to use its Tiangong space station for 10 years, during which astronauts will work for six-month periods.