The US military will station a powerful radar and a space telescope in Australia as part of its strategic shift towards Asia, the two countries have announced.
US Defence Secretary Leon Panetta described the deal as a "major leap forward in bilateral space co-operation and an important new frontier in the US' rebalance to the Asia-Pacific region".
The transfer of the C-band radar "will add considerably to surveillance of space debris in our part of the world," Australian Defence Minister Stephen Smith told a news conference on Wednesday.
The plan, unveiled at annual strategic talks between the two nations attended by US Secretary of State Hillary Clinton, will also allow Americans to track Chinese space launches, senior US defence officials said.
"It will give us visibility into things that are leaving the atmosphere, entering the atmosphere, really all throughout Asia", including China's rocket and missile tests, a US defence official told reporters on condition of anonymity.
At the meeting of foreign and defence ministers in the western Australian city of Perth, the two governments also launched discussions on granting the Americans future access to air bases in northern Australia as well as naval ports, including one in nearby Stirling, Smith said.
'Here to stay'
Before Wednesday's meeting Clinton vowed that the US was fully committed to its pivot to Asia over the long term, despite crises in the Middle East and budget pressures at home.
Speaking on Tuesday at the University of Western Australia, she underlined America's "expanding engagement" in the region.
"It's important that we make absolutely clear we are here to stay," she said, adding that it was important to see India become more involved in the region and that the US would welcome Australia-India joint naval exercises.
US Marines were deployed this year in Australia's north; 250-strong contingents will spend six-month tours.
Smith said the two sides would soon increase the number of Marines on the ground to 1,100 by 2014, with the goal of 2,500 Marines in place by 2016-17.
US officials have grown anxious over China's growing military might and territorial tensions with its neighbours, notably, Japan, and are pushing for a more visible military role across the region.
This includes expanding military exercises and deploying more advanced ships and hardware, particularly in southeast Asia.
Although US and Australian officials privately worry about Beijing's assertive stance in the South China Sea and elsewhere, Clinton insisted the US supported the peaceful rise of China.