The McDonnell Douglas F-15 Eagle, after more than 25 years of service, was still the U.S. Air Force's premier fighter as the year 2000 approached. It is the only aircraft in the U.S. Air Force arsenal capable of launching the ASAT anti-satellite missile. It also serves with the air forces of Israel, Japan and Saudi Arabia. The F-15 constantly is upgraded to include state-of-the-art equipment. It can penetrate enemy defenses and can outperform and outfight any current or projected enemy. The Eagle's air superiority is due to its advanced avionics, its range and weaponry, and its unprecedented maneuverability. One person can effectively perform air-to-air combat using its advanced systems to detect, acquire, track and attack enemy aircraft. The single-seat F-15C and two-seat F-15D models were followed by the two-seat, dual-role F-15E "Strike Eagle," the world's most technologically advanced fighter.