On Friday, China’s foreign ministry acknowledged the imminent uncontrolled reentry of the Long March 5B as the orbit of the first stage continued to lose altitude.
On May 7 at a Foreign Ministry regular news conference, spokesperson Wang Wenbin responded to a question stating that it is “common practice across the world for upper stages of rockets to burn up while reentering the atmosphere.”
The second Long March 5B rocket successfully launched the Tianhe core module for China’s space station late April 28 Eastern. It soon became apparent, that the first stage had also reached orbit and was slowly returning to Earth.
The latest prediction from the Aerospace Corporation shows blue and yellow ground tracks over which the rocket body will pass during the predicted window between 10:13 a.m. Eastern Saturday, May 8, and 4:13 a.m. Sunday, May 9.
China Ministry spokesperson on the issue
Wang said, “China is following closely the upper stage’s re-entry into the atmosphere. To my knowledge, the upper stage of this rocket has been deactivated, which means that most of its parts will burn up upon reentry, making the likelihood of damage to aviation or ground facilities and activities extremely low. The competent authority will release relevant information on time”. Wang acknowledged there was risk associated with the reentry but that this was “extremely low,” an assessment shared by space debris modeling experts.
The “upper stage” referred to by Wang is also the first and the largest stage of the Long March 5B. While most upper stages enter orbit and eventually reenter due to atmospheric drag, the first stages of most expendable rockets do not reach orbital velocity and reenter the atmosphere and land in a pre-defined reentry zone.
The Long March 5B core stage’s orbital inclination of 41.5 degrees means the rocket body passes a little farther north than New York, Madrid, and Beijing and as far south as southern Chile and Wellington, New Zealand, and could make its reentry at any point within this area.
Governed by voluntary guidelines
As per Christopher Newman, a professor of space law and policy at Northumbria University, there are no international laws that dictate how the re-entry of space objects is supposed to be accomplished.
According to Hugh Lewis, a professor at the University of South Hampton, “there are numerous spent rocket bodies in orbit that will make an uncontrolled re-entry.
Holger Krag, head of the Space Safety Programme Office for the European Space Agency, said last week that an average mass of about 100 tons is re-entering in an uncontrolled way through 50-60 individual events per year.
In the case of damage, Newman says The Liability Convention of 1972 provides a little more clarity on this, with Article II of the 1972 convention making a State absolutely liable should a space object or part of a space object be shown to cause damage on Earth or to an aircraft in flight. Significantly, in practical terms, engaging the Liability Convention is as much a foreign policy decision as a legal one, says Newman. “The ‘victim’ state may be heavily dependent on the ‘liable’ state for infrastructure or investment and might not wish to rock the boat. So it is by no means certain that the 1972 Convention will be invoked.”
“It’s not hard law that’s binding on countries, only a voluntary guideline, and that’s because countries like the United States did not want to create a binding law as they sometimes need to deviate from it themselves,” says Weeden. China is planning two further Long March 5B launches in 2022 to send two experiment modules to join Tianhe in orbit. How China will respond to this situation, which has detracted from the successful Tianhe launch, remains to be seen.
Ultimately, Weeden says, mission requirements, in absence of hard law, may win out.