HELSINKI — Debris from a large Chinese rocket stage fell into the Indian Ocean late May 8 Eastern as people around the world watched for signs of the fiery reentry event in the skies.
Remnants from the roughly 30-meter-long, five-meter-wide empty core stage of the Long March 5B fell into the Indian Ocean at 10:24 p.m. Eastern close to longitude 72.47 degrees east and latitude 2.65 degrees north, China’s human spaceflight agency, CMSEO, announced.
Data from the U.S. Space Force’s 18th Space Control Squadron space tracking later confirmed reentry occurred at approximately 10:15 p.m. Eastern over the Arabian Peninsula, adding that “It is unknown if the debris impacted land or water.
Sightings and videos were posted on social media platforms May 8 as the rocket begin its last orbits around the Earth.
The Long March 5B successfully launched China’s first space station module directly into low Earth orbit April 28 Eastern.
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 size of the stage, travelling at 7.8 kilometers per second and orbiting once every 90 minutes between 41.5 degrees north and 41.5 degrees south latitude, quickly became a matter of both space industry and public interest.
Claimed observation from Oman which if genuine would imply the reentry was underway with impact over the Indian Ocean https://t.co/Ix6nqUv20d
— Jonathan McDowell (@planet4589) May 9, 2021
The U.S. Space Force’s 18th Space Control Squadron (18 SPCS), EU Space Surveillance and Tracking (EU SST), the Aerospace Corporation and others provided regular reentry prediction updates as the orbit of the rocket stage decayed.
Variables such as atmospheric fluctuations meant reentry prediction windows spanned days earlier in the week, and narrowed in a two-hour window around four before expected reentry. While most of the stage was likely to burn up, components made of heat resistant materials, such as tanks and thrusters made stainless steel or titanium, can reach the ground.
Rocket stage fallout
Major media covered the story intensely in the days before the reentry, reporting on aspects including potential timing and location, international law, previous large uncontrolled reentries such as Skylab and Salyut 7, with the uncertainty of timing and location likely a factor in the widespread interest.
White House press secretary, Jen Psaki, said Wednesday that the “United States is committed to addressing the risks of growing congestion due to space debris and growing activity in space and we want to work with the international community to promote leadership and responsible space behaviors.”
Chinese media remained largely silent on the event until after a May 7 foreign ministry press conference in which spokesperson Wang Wenbin said China is following the event closely and stated that the likelihood of damage to aviation or ground facilities was “extremely low.”
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.
The false equivalence was also echoed in online comments by some displeased with the coverage of the reentry, juxtaposing headlines from the Chinese 5B first stage coverage with reports following the reentry of a SpaceX Falcon 9 second stage over Washington state in March after a Merlin engine was unable to restart and effect a reenter over the Pacific Ocean.
Most expendable rocket first stages do not reach orbital velocity, instead reentering the atmosphere soon after launch and falling within a predefined, uninhabited reentry zone. Smaller upper stages often perform deorbit burns to lower altitude to reduce time in orbit and lower chances of collisions with other spacecraft or to immediately reenter the atmosphere.
Global Times, a Beijing tabloid under the auspices of the People’s Daily, an official newspaper of the Central Committee of the Chinese Communist Party, decried “Western” coverage. It claimed that characterizations of “out of control” wreckage was an “invented concept,” citing space experts. “In Western media’s standard, Space X’s Falcon 9 is also out of control wreckage,” the article claimed.
One interviewee for the article said the continuous hype was “an old trick used by hostile powers every time they see technological breakthroughs in China, as they are nervous.”
Next space station launches
China is planning two further Long March 5B launches in 2022 to send two experiment modules, named Wentian and Mengtian, to join Tianhe in orbit. If and how China will respond to this situation, which has detracted from the successful Tianhe launch, remains to be seen.
China’s Tiangong-1 made a high-profile, uncontrolled reentry in 2018, burning up over the South Pacific, two years after losing contact with the spacecraft. Tiangong-2 was deorbited in a controlled manner in 2019 after hosting crew and refuelling in microgravity verification tests.
The Long March 5B reentry could result in a call for action on increasingly pressing issues of space traffic management and space debris. The apparent acrimony over the event however suggests hurdles to constructive discussion.
Brian Weeden of the Secure World Foundation told SpaceNews that while there is an emerging international norm towards controlled de-orbiting of rocket stages, it’s definitely not universal.
“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’s next space station related launch is expected within weeks, with a Long March 7 rocket to launch the Tianzhou-2 cargo spacecraft to join Tianhe in orbit. The crewed Shenzhou-12 mission is likely to follow in June. Neither mission will involve uncontrolled reentries of first stages.