In the remote Pilbara region, in Western Australiaa was found 500 kg space debris still engulfed in flames: the report arrived around 2pm on Saturday 18 October, when some miners reported seeing a “space ball” falling from the sky. As confirmed byAustralian Space Agency in a post about X, this detritus of space junk it could be “a propellant tank or pressure vessel from a space launch vehicle.” According to several experts, it is likely that the debris in carbon fiber comes from a Chinese rocket, although this version has not yet been officially confirmed.
Even though it caused no damage, the fall of this space debris has put the spotlight back on the possible risks associated with it uncontrolled return of space objects, bringing to mind some precedents, such as that of the Long March rocket – also from the Chinese space agency – which fell to Earth in 2022.
What we know about the dynamics of the fall
Space debris was found burning near an iron mine in Western Australia, about 30 km from the city of Newmanin the Pilbara region: the photographs released by the police also seem to confirm from the shape that it is indeed a tank.
Although the Australian Space Agency has confirmed the launch of new ones technical analyses to identify the origin of the debris, according to various experts – including Jonathan McDowellastronomer specializing in space launches – it would seem to be part of the last stage of the Chinese rocket Jielong-3 (in English Smart Dragon 3) launched on September 24, 2024. Indeed, the tracking of the space object’s trajectory (seen below) is perfectly compatible with a passage over the Pibara region in the early hours of October 18.
To underline, then, there is the fact that the tank was in carbon fibera material capable of resisting very high temperatures: the possibility was therefore foreseen that the object would not completely disintegrate during re-entry into the atmosphere.
The issue of uncontrolled returns
The affair once again raises a theme that arose with the “Long March question” of three years ago, that is, the uncontrolled return of some Chinese rockets: unlike Western space agencies, in fact, Beijing’s does not provide for the controlled return of all the rockets it launches into orbit.
Among the most recent examples there is certainly the episode of the Chinese Long March 5B rocket, which returned to Earth in an uncontrolled manner in 2022, without however causing damage and ending up in the sea between Malaysia and the Philippines. The issue also raised controversy because Beijing’s space activity is under the control of the Military Department, therefore covered by military secrecy: this means that many details of their activity are not revealed to the international community.
But what does it mean for a rocket to return in a controlled manner? For years now it has been the practice to return as much material launched into orbit as possible, to avoid the accumulation of space junk. When returning, however, to prevent it from ending up in inhabited areas or causing damage, it is placed on a spiral trajectory previously calculated so as to end up in safe areas. Often the point chosen by space agencies is the Nemo Pointin the heart of the Pacific Ocean, the furthest place from any landmass.
This procedure, however, was not put into practice in the case of the Long March, and this raised some concerns – although largely unfounded – about a real danger that some debris could fall on someone’s head or cause damage to property.
Western Australia is no stranger to impacts of large space debris, even in the case of controlled re-entry: in 2022 a farmer found a 3 meter high fragment of the trunk of the capsule used by SpaceX to carry 4 astronauts on the International Space Station during the Crew-1 mission in 2020. That episode was one of the most emblematic in the area after the return of the Skylab space station in 1979, whose debris ended up between Australia and the Indian Ocean, but without causing any damage.
