Nine years after a six-tonne asteroid crashed through the Earth's atmosphere over South Australia, researchers have used a combination of defence satellites, weather radars and drones to locate the largest meteorite-strewn area in Australia since the Murchison meteorite fall in 1969.
A team of researchers from Curtin University, Monash University and the Bureau of Meteorology drew on information captured by both US Department of Defence satellites and local weather radar data to determine the likely location of surviving meteorites, which they then honed in on using drones and artificial intelligence.
Dr Hadrien Devillepoix from Curtin University's Space Science and Technology Centre (SSTC) said the discovery was the first time meteorites have been found using non-US radar data, made possible by the Bureau of Meteorology having recently made its own weather radar data available for research.
"Access to the weather radar data gives us the ability to track meteorites as they fall through the lower atmosphere, similar to rain," Dr Devillepoix said.
"We found meteorite signatures for the 2013 event, allowing us to map the 6km fall zone just north of Port Augusta.
"Guided by a new technique developed by SSTC's Seamus Anderson, meteorites were automatically identified in drone survey images of the fall zone.
"Using artificial intelligence and machine learning to map a meteorite strewn field is a world first and searching such a large area on foot would have taken weeks rather than days."
Professor Andy Tomkins from Monash University led the field search, recovering a total of 44 samples, weighing just over 4kg.
"These samples are all from a six-tonne asteroid that would have broken up high in our atmosphere and this event is exciting as it is the first strewn field discovered since the famous Murchison meteorite fall in 1969," Professor Tomkins said.
"Samples were carefully collected to avoid any contamination by microbes from outside the natural environment, following the directive of Monash University microbiologist Dr Rachael Lappan.
"Dr Lappan and her team will now undertake the first study of how microbes interact with a newly fallen meteorite.
"This is an opportunity to test the theory that as microbes first move into a new environment, they initially survive by consuming minerals and even gases from the atmosphere."
The Bureau of Meteorology's Dr Joshua Soderholm said using radar data to help locate the meteorite remnants was an exciting new application for the technology.
"The Bureau's weather radars are used primarily for monitoring precipitation but are also able to detect anything present in the sky, including birds, bats and insects, however using them to hunt for meteorites was unprecedented," Dr Soderholm said.
Mr Ben McHenry from the South Australian Museum, where a collection of stones from the meteorite will soon be displayed, said the samples were an invaluable addition to the museum's collection.
"This is a terrific collaboration between the universities, the Bureau of Meteorology, the Australian Synchotron and our museum to share the excitement of this discovery with the public."
The samples will be on display at the South Australian Museum from November 26 2022 - February 5 2023 as part of the Six Extinctions exhibition.
Scientists from Monash and Curtin are undertaking further research on the meteorites and looking to apply the radar technique to other meteorite and space debris falls.
