The collection of SpaceX debris from sheep and cattle farms NSW Snowy Mountains has begun, although space experts are asking why it hasn't happened sooner.

Pieces of the SpaceX Dragon capsule have been discovered in the region since July 9, after residents heard a loud bang believed to be from the spacecraft re-entering the Earth's atmosphere.  

Four separate fragments were found on farms near Dalgety, Jindabyne and Tumbarumba, which are now being secured by the Australian Space Agency. 

"The Australian Space Agency has begun collecting the space debris found in the Snowy Mountains region of NSW, inline with our international obligations," said a spokesperson from the Australian Space Agency. 

Confirmation that the pieces are being collected comes as no surprise to US astronomer at the Harvard--Smithsonian Centre for Astrophysics, Jonathan McDowell.

He has described it as a "reasonable approach" but has noticed it has been a process.

"It's taken a while and I think part of that is probably from figuring out whose job is it to do that," Mr McDowell said. 

"To have the Australian Space Agency, which is a pretty new agency, let's remember, go out and do this seems like the right move."

Mr McDowell says the return of space debris back to its country of origin will be used as a learning curve, and the incident continues to fuel debate about debris re-entry management.

"It's really a matter of a few pieces being sent back to the manufacturers to let them study how incompletely they burned and maybe inform how they can then improve the design," he said. 

"Every time a debris survival like this happens, it adds to the feeling of needing to be more careful and more tidy than we have been."

Some to stay, some to leave

The Australian Space Agency, which was established in 2018, has thanked the landholders in the Snowy Mountains, or "debris finders", for forming part of "efforts to improve global knowledge that will make space activities more sustainable."

ANU space law expert Dr Cassandra Steer always anticipated that the pieces would be sent back to the US in line with international treaty obligations, but says it should have been a faster process. 

"The US is responsible and then SpaceX would only be responsible under domestic US law if there were any costs to recover," she said.

"I think they (ASA) could have been in action quicker and they could have been communicating publicly a lot more fluidly."

Dr Steer says there's a possibility the pieces sent overseas could come back to Australia, but that decision will be made between governments in time. 

"The US can say to Australia that we could keep the debris if we wanted to study it or put it in a museum," she said.

The Australian Space Agency is urging the community to not handle pieces of space junk, and to report any sightings to [email protected].

SpaceX and NASA have been contacted for comment.