It’s been a mixed month for China’s space programme.
The spacefaring nation scored a stunning achievement over the weekend when it successfully landed a rover on Mars, becoming the third country after the United States and the Soviet Union to pull off the challenging feat.
Less than a week before, though, China’s space programme was grabbing headlines for a far less impressive development. One of its Long March rockets that had transported the first piece of the country’s new space station into orbit had an uncontrolled re-entry into Earth’s atmosphere. Most of it burned up, but bits and pieces of it crashed into the Indian Ocean near the Maldives.
Fortunately, the debris did not hit a populated area. But experts were guessing for several days just where it could touch down. According to space debris trackers, the rocket could have fallen anywhere on Earth between New York City and New Zealand.
Chinese officials downplayed the mishap, but this is not the first time that a piece of Chinese space hardware has made an uncontrolled landing, and the latest incident highlights the need to mitigate a larger space debris issue.
A space station launches
The Long March 5B is one of China’s largest rockets, capable of lifting heavy payloads into orbit, namely segments of the country’s planned space station. The first of those pieces, named “Tianhe”, or “Harmony of the Heavens”, launched into orbit on April 29, blasting off from the Wenchang Space Launch Center on the southern island of Hainan.
The module contains living quarters for a three-person crew on the country’s planned permanent space station that is expected to be complete by the end of 2022.
It’s one of three main components of the newly commissioned orbital outpost, similar to the International Space Station (ISS).
China was barred from participating in the ISS programme with the US but is in potential talks with Russia on a future space partnership.
It will take several launches to complete the burgeoning outpost, but the country plans on launching its first set of astronauts to the new module sometime in June. A trio of astronauts will help set up the living quarters and perform a variety of research investigations during a planned three-month mission.
Typically after a launch, the re-entry of rocket hardware is normal, landing in a controlled fashion either in the ocean or on a barge, as was the case with SpaceX.
However, this wasn’t the case following the Tianhe launch last month. The massive launcher that delivered it to space was, for the most part, expected to burn up during its fiery entry into the Earth’s atmosphere.
However, no other launcher in the world leaves such a massive component to fall back to Earth in an uncontrolled manner. It’s also unclear whether the rocket even had the capability to deorbit itself safely to begin with.
The US military warned it would be difficult to predict where the rocket would land and when and how much material might hit the ground, but kept a close eye on its trajectory.
The Chinese government, on the other hand, insisted that the risk of the hardware landing in a populated area was low.
“The probability of causing harm to aviation activities or [on people and activities] on the ground is extremely low,” a spokesperson for the Chinese foreign ministry said.
The Earth is made up of roughly 70 percent ocean, so it makes sense that whatever remnants were left would most likely splash down in water. However, the incident represents a growing issue in space as more and more countries and government agencies join the space sector.
This isn’t the first time that a piece of Chinese hardware has made an uncontrolled landing. In July 2019, China’s previous space station, called Tiangong-2, began to make its descent back to Earth after being decommissioned.
The Chinese government also downplayed the risk to populated areas, as it was able to target a specific landing area in the Pacific Ocean thanks to minimal onboard fuel reserves. (Its predecessor, Tiangong-1 also made an uncontrolled splashdown in the Pacific Ocean.)
That incident was followed by another piece of space junk, a different Long March 5B rocket, which slammed into the Ivory Coast after re-entering the Earth’s atmosphere over a metropolitan area in May 2020.
That rocket’s uncontrolled re-entry path was largely determined by space weather, Jonathan McDowell, an astrophysicist with the Harvard Center for Astrophysics, told Al Jazeera.
“Particles streaming from the sun can create drag and perturb the path of such a fast-moving piece of debris in ways that make its passage difficult to predict,” McDowell explained.
Hanspeter Schaub, a professor in the aerospace engineering sciences department at the University of Colorado Boulder, agrees, saying that impacts from these types of uncontrolled landings in populated areas are uncommon.
“It’s really rare to see something the size of this Chinese rocket come down,” Schaub told Al Jazeera.
“Satellites and other objects in space do come down, sometimes within months, sometimes within years or decades after being launched. Most are designed to burn up in the atmosphere so that very few parts make it to the ground,” Schaub added.
Bill Nelson, NASA’s newly appointed administrator, criticised China, saying the country acted irresponsibly.
“Spacefaring nations must realise the risks to people and property on Earth of re-entries of space objects and maximise transparency regarding those operations,” he said in a statement.
Nelson also warned that with more Chinese launches on the horizon, this type of incident could happen again.
“It’s clear that China is failing to meet responsible standards regarding their space debris,” he added.
The issue of space debris is not new but is expected to grow as more nations build space programmes and more objects are launched into space.
“Space debris has been known for a while, but now you have more competition in space,” Joanne Gabrynowicz, a professor at the National Center for Remote Sensing, Air, and Space Law at the Mississippi School of Law, told Al Jazeera.
“You don’t just have two spacefaring nations – the Chinese are becoming very significant, as is the European Space Agency, among others. When you have more actors and more stuff, it gets more complicated,” she added.
There’s no law on the books currently that forbids pieces of rockets from crashing to Earth’s surface. But there are rules in place that say who is responsible when it comes to damage or injury from space junk.
But most of the rules governing outer space were created decades ago when the space race first began, and as such do not account for the growing number of players and hardware. The Outer Space Treaty, which came into force in 1967, remains the basic framework on international space law.
It defines what international players are legally allowed to do in space, while another piece of legislation — called the Liability Convention — specifies who is responsible for space objects that cause damage or harm.
This means that if part of this particular Long March 5B rocket caused any sort of physical damage in one of the countries that supports the Liability Convention, that country could hold China financially responsible.
But it’s not quite that simple. Invoking the convention could prove to be more of a political move than a legal move. Unless the rocket debris specifically impacted infrastructure or government property, chances are that a country wouldn’t do anything about it.
In this case, the rocket landed safely in the Indian Ocean without causing any damage, but that won’t always be the case. That’s why scientists say new policies are needed to help mitigate the growing problem of space junk.