The US Navy has awarded a $169 million contract for its new Sidewinder AIM-9X missiles to Hughes Missile Systems of Tucson, Ariz. Sidewinder missiles use infrared technology to seek out enemy aircraft by locking on to the heat signatures of their exhaust systems. The new device, which the company plans to complete by 2002, employs advanced sensors that allow it to "see" and target an entire aircraft without being fooled by countermeasures such as flares. Pentagon officials said the contract could be worth as much as $421.7 million if the parties exercise all options.