The United States military is to station a powerful radar and a space telescope in Australia as part of a major refocusing of priorities towards Asia.
A US Air Force C-band radar will be deployed in the southern hemisphere, allowing the Americans to better track space debris.
The agreement came during annual defence talks between Australia and the United States in Perth, which were attended by Secretary of State Hillary Clinton and Defence Secretary Leon Panetta.
The ABC reports the cost of getting C-band radar operational in Australia is about $A30 million, with an annual cost of around $A10 million after that.
It will be set up at Exmouth, in the north west of Western Australia. No US military will be permanently stationed with the equipment.
A space-surveillance telescope will also be transferred from New Mexico to Australia. The ABC reports it is designed to track small objects at altitudes of 35,000km.