China’s Long March 5B rocket makes splash, but good news burns up in the atmosphere
- Casualties avoided, but China is criticised for failing to plan a ‘targeted re-entry’ to determine where debris would land
- The rocket and its predecessor – debris from which landed in Africa – have made the largest uncontrolled descents in 30 years, amid differing views on the risks
As the rocket was re-entering the Earth’s atmosphere on Sunday, US space agency Nasa said China had failed to “meet responsible standards”, before China hit back, saying the operation was conducted within international law.
Space operation experts said that the criticism of China was based on established space practice, but the descent of the Long March 5B highlighted differences between Chinese and US views, magnified on this occasion by the giant size of the launcher rocket and China’s failure to plan a “targeted re-entry” of its debris.
China announced that the “great majority” of the debris had burned up before it reached the Indian Ocean near the Maldives – confirming its earlier prediction that it was unlikely to cause any harm.
Debris from China’s Long March rocket lands in Indian Ocean, drawing criticism from Nasa
Before the announcement, Nasa administrator Bill Nelson said that all spacefaring nations should minimise risks to people and property on Earth, and maximise transparency.
“It is clear that China is failing to meet responsible standards regarding [its] space debris,” he said in a statement. “It is critical that China and all spacefaring nations and commercial entities act responsibly and transparently in space to ensure the safety, stability, security and long-term sustainability of outer-space activities.”
His remarks were rejected by Chinese foreign ministry spokeswoman Hua Chunying, who said on Monday that Western nations had adopted double standards over China’s mission. She said it had adhered to international law and Beijing was willing to expand cooperation with other nations on space matters.
Jonathan McDowell, an astrophysicist at the Harvard-Smithsonian Centre for Astrophysics, said the concern about safety was triggered by damage caused in Africa last year by the first Long March 5B rocket.
“Each launch of the CZ-5B, unless its design is changed, will carry the same risk of debris hitting the ground,” McDowell said, noting that the two Long March 5Bs had made the largest uncontrolled re-entries in 30 years.
“[This] second CZ-5B was lucky; it went in the Indian Ocean. The first one was less lucky; it caused damage in West Africa. Will the third be lucky or unlucky? It could go either way. The problem is that China and the West have different perspectives on what small level of risk to the public is acceptable.”
McDowell said China should avoid putting objects weighing 10 tonnes or more in orbit without a plan to dispose of them safely in a specific location.
“There has been a general practice that objects above about 5 metric tonnes in low Earth orbit should be safely disposed of, since about 1990,” he said.
In 2000, Nasa redirected the Compton Gamma Ray Observatory satellite when the spacecraft entered the Earth’s atmosphere, and its debris fell in a remote area of the Pacific Ocean.
China Space News, an official media outlet under the Chinese space administration, said on Tuesday that designing a “targeted” re-entry would have reduced the weight the rocket could carry, so China opted against it, given the low probability of debris endangering people.
The Long March 5B is 53.7 metres (176 feet) in length. The rocket stage that de-orbited was 33 metres long and weighed more than 20 tonnes, making it the sixth-largest object to re-enter the Earth’s atmosphere, according to the Aerospace Corporation, a government-funded research organisation in California.
Very little of the rocket stage’s mass survived re-entry, with the majority burning up as it entered the Earth’s dense atmosphere at about 8km (five miles) per second.
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Nick Brown, a space systems specialist and director of research and analysis at defence publisher Janes, said the fate of China’s previous 5B rocket had added to global interest this time.
“International legislation on the liability for damage caused by space objects is imperfect, and there is ambiguity around definitions of what constitutes negligence, but if debris from the second 5B had also made landfall and caused damage – or loss of life – that would no doubt have exacerbated accusations that China was being irresponsible with its space delivery systems,” Brown said.
The Long March 5B re-entry also brought renewed attention to congestion in space. It is believed that there are more than 2,000 rocket bodies orbiting Earth, all technically uncontrolled.
According to CelesTrak, which monitors orbital objects, 1,035 of them are Russian, including some from the Soviet era, while 546 are American and 170 Chinese.