Developments since 1983 in U.S. missile defense efforts:
— March 23, 1983: President Ronald Reagan announces plans for an extensive program to examine the feasibility of a missile defense program. The concept — derided as "Star Wars" by opponents in Congress — revises the nation's 35-year-old nuclear strategy by focusing on missile defense rather than the ability to retaliate against nuclear attack.
— June 10, 1984: An Army interceptor destroys a target missile over the Pacific Ocean.
— Sept. 6, 1985: A Titan rocket is destroyed by an infrared advanced chemical laser.
— January 1991: The first operational engagement between ballistic missiles and ballistic missile defenses occurs during the Gulf War.
— April 1, 1997: The Ballistic Missile Defense Organization establishes the Joint Program office to design and develop a system by 2003.
— April 30, 1998: Boeing gets a $1.6 billion contract to be the lead systems integrator for the program.
— July 23, 1999: President Clinton signs the National Missile Defense Act. He says threat, cost, technological status and adherence to a renegotiated Anti-Ballistic Missile Treaty are the four criteria in making his decision to deploy such a system.
— Aug. 17, 1999: The United States and Russia resume strategic arms talks that include modification of the ABM Treaty.
— Oct. 2, 1999: The first integrated flight test successfully intercepts its target.
— Jan. 18, 2000: The second integrated flight test fails, due to moisture inside the "kill vehicle" — the weapon section of the interceptor — which prevented it from using heat-seeking devices to detect its target.
— July 7, 2000: The third integrated flight test fails when the kill vehicle fails to separate from its booster rocket.
— Sept. 1, 2000: Clinton decides not to authorize work to begin on deploying national missile defense, on grounds that the reliability of the technology had not been proven.
— Dec. 28, 2000: Boeing is awarded a new, six-year, $6 billion contract for national missile defense.
— April 10, 2001: Russia, China and North Korea tell the U.N. Disarmament Commission that a U.S. missile defense system would threaten international security, trigger a new arms race and undermine the ABM Treaty.
— May 1, 2001: President Bush declares, "We need a new framework that allows us to build missile defenses to counter the different threats of today's world."
— June 27, 2001: The proposed 2002 defense budget is submitted to Congress, allotting $7 billion — later amended to $8.3 billion — for missile defense.
— July 14, 2001: The scheduled fourth integrated flight test was to be the first since Bush took office. Each test costs around $100 million.
Sources: Center for Defense Information, Ballistic Missile Defense Organization and Facts on File.