Australia has ordered 350 AIM-9X Block 2 Sidewinder air-to-air heat seeking missiles (plus lots of training, maintenance and ancillary gear) for about $1.1 million each. Australia has until now used the ASRAAM, which entered service in 2002. Mainly developed by Britain ASRAM is an 88 kg (194 pound) missile with a range of 18 kilometers and a high capability heat seeker sensor system. AIM-9X Block 2 is considered more advanced and the F-35 and F-18 were designed to use it.
The AIM-9X Block 2 is the latest version of the Sidewinder, a missile that has come a long way since it first appeared in the 1950s. In the last 25 years these short-range heat-seeking missiles have accounted for some 90 percent of losses in air-to-air combat. Sidewinder still dominates the market, despite a lot of competition from the likes of IRIS-T, ASRAAM, Magic, Python, Molinya, and several Chinese clones of foreign designs.
Australia is in the midst of upgrading its air force. The purchase of another 58 F-35 fighters was recently approved. This will give Australia 72 F-35s, enough to equip three squadrons. These, in addition to 24 F-18F fighters and twelve EA-18G electronic warfare aircraft will be the primary Australian air combat force in the future. This is a modification of the original plan drawn up over a decade ago.
All this was part of an evolving Australian strategy to eventually obtain American F-35s. It worked like this. In 2009, after over four years of deliberation, Australia decided to begin buying U.S. F-35 fighter-bombers. The first 14 were ordered, at a cost of over $100 million each. The price includes a lot of training and maintenance infrastructure. The plan was to replace the existing force of F-111 bombers and F-18B fighters with F-35s. The worn out 1960s era F-111s were finally retired in late 2010, after 37 years of service.
Then in 2007 Australia had been told that the F-35s would not arrive until 2018. That meant an interim aircraft would be needed. Meanwhile, Indonesia was buying Russian Su-30 fighters. In response, Australia bought 24 American F-18F fighters, for about $100 million each (including spare parts, training and such). Australia already operates 72 of the older, and smaller, F-18B and these will be retired by the end of the decade. While the two versions of the F-18 have a lot in common (about 25 percent commonality in parts), the F-18F is a new, and larger, design that is based on the original F-18. The F-18Fs provide Australia with a high performance fighter-bomber that could cope with the Su-30. The F-18Fs will last into the 2020s, especially since it was decided to convert six of them into F-18Gs. So Australia will end up with 72 F-35s, 18 F-18Fs and six EA-18Gs.