Key Points
- A large mystery object washed ashore on a remote WA beach earlier this month.
- The Australian Space Agency determined it is likely part of a rocket.
- A growing amount of space debris is littering Earth's orbit.
The small coastal town of Green Head in Western Australia was thrown into the spotlight last week after a large mystery item floated in with the tides on the previous weekend.
After a couple of days of speculation and a police guard on the giant canister-like item measuring about 2.5 metres by three metres, the Australian Space Agency determined it is likely part of a rocket.
“The object is most likely a solid rocket motor casing. We're continuing the process of identifying the type of rocket & its origin through ongoing engagement with our global counterparts," the Australian Space Agency said on Twitter on Wednesday afternoon.
The odd find has sparked many questions about how it got there and who is responsible for it.
What is space debris?
Iver Cairns, a professor in space physics at the University of Sydney, said like the locals who found the item about 300 kilometres north of Perth, he was intrigued by it, having seen photographs of it.
“I did immediately think that looks like a pressure vessel that might be part of a rocket,” he said
Cairns explained that some parts of spacecraft are designed to detach and fall away from the main body once they are no longer required.
"If it's a two-stage or more than one-stage rocket, then at some stage it will run out of fuel in the first stage, and when that happens, the remainder of the rocket, so the second stage and whatever payload it has, becomes separated," he said.
Cairns said with the pull of gravity, the first stage would usually eventually fall to Earth.
Along with rocket parts, a growing amount of space debris, including old satellites or parts of satellites and non-functioning spacecraft, also remain in orbit around the Earth.
Who is responsible for space junk?
While no single global body has the power to regulate space, Cairns said many of the main spacefaring countries do have an agreement about taking responsibility for hardware sent into space.
"There's the Committee on the Peaceful Uses of Outer Space (COPUOS) treaty which is a United Nations Treaty, and that applies to the signatories," he said.
More than 100 nations, including Australia, have signed the treaty.
Cairns said the agreement outlined that those who send items into space are responsible for them and makes mention of "compensation associated with one nation state's material impacting another one and causing damage".
"I understand that Australia as a signatory has a line item in the budget [to deal with costs associated with incidents related to space debris] the annual budget for Australia, which is, I understand, $1 billion," he said.
Cairns said he was aware of just one attempt by a nation to make use of elements within the COPUOS treaty in regard to dealing with space-related debris that had fallen to Earth.
Parts of a Soviet nuclear-powered surveillance satellite, known as Kosmos 954, fell to Earth in 1978, landing in Canada.
Taking responsibility for debris in space
The Indian Space Research Organization has launched more than 100 space craft missions over the past few decades. Source: AAP / INDIAN SPACE RESEARCH ORGANIZATION HANDOUT/EPA
He said one of those was a United States regulatory group that had told operators based in that country that within the next few years, anybody putting something into orbit would need to have mechanisms for the safe disposal of their satellite or their object within a certain amount of time after it becomes non-operational.
Cairns said more operators were making efforts to at least recover their first-stage rockets, including Elon Musk's company SpaceX.
"SpaceX has found a way to control their first stage rockets so that they will come back down to earth and land safely on a barge, for instance," he said.
Although debris owned by the company did make its way to Earth without warning last year when
Should we be worried about all the man-made items floating in space?
Australian farmers in the NSW Snowy Mountains discovered debris from a SpaceX craft on their land last year. Source: AAP / Brad Tucker/Cover Images
"So we're going to expect more and more come down, and we're going to expect more rocket launches, so much more first stage rockets bodies," he said.
Although Cairns said considering the probabilities of space debris making its way to Earth in the first place were low and that it may fall on land even lower, the threat of space junk hitting people going about their everyday lives was not something people needed to fear.
"There's also the fact that so far, as far as I'm aware, nobody has been killed or significantly injured by material coming back to Earth from space during, let's say, the last 200 years," he said.
"And the groups that have control over their spacecraft or other objects reentering do try and dispose of them in what they call the satellite graveyard near Point Nemo in the South Pacific."
He pointed out that space debris had the potential to interfere with space travel and exploration as the amount of it in orbit around the Earth increased.
"These things (space debris) sometimes hit each other, and when they do so, they generally break apart, and you get a cascade down via mini collisions down to smaller and smaller objects, some as tiny as paint flecks," he said.
Cairns said NASA space shuttles had evidence of the impact of these small pieces of paint.
"They would occasionally find places on their viewing windows where there were little impact craters associated with just flecks of paint that hit the shuttle and vaporise a tiny amount of the glass," he said.
The Green Head space debris
Locals were intrigued by what the strange item that washed up on the beach could be. Source: Supplied / Ken Puls
Cairns said if such an item had fuel in it, it could have posed a danger to those coming in contact with it as it may be carcinogenic.
"One of the fuels, for instance, one that's quite often used in thrusters, is called hydrazine, and it's bad news. Others might just be hydrogen and oxygen, for instance, but under pressure, if someone pokes a hole in the pressure vessel, it's not going to be good," he said.
After consulting with state and national agencies with expertise in maritime, aviation, defence and space industries, police removed it from the beach, taking it to an undisclosed location.
The Australia Space Agency is working on the ongoing assessment and identification of the item.
