List of Topics

SfC Home > History > Strategic Defense Initiative >

Overview of the Strategic Defense Initiative (SDI)

by Ron Kurtus (updated 31 May 2023)

An important program during the administration of President Ronald Reagan was the Strategic Defense Initiative (SDI). This program was also called "Star Wars" by the popular press.

It was a proposed defensive shield to shoot down enemy missiles. The program was very expensive but resulted in winning the Cold War with the Soviets.

Questions you may have about SDI are:

This lesson will answer those questions.

Concept of SDI

The concept for the Strategic Defense Initiative came from a casual conversation between the renown scientist and "father of the hydrogen bomb" Dr. Edward Teller and President Reagan.

Teller proposes x-ray lasers

Dr. Teller told Reagan of an idea he had about using x-ray lasers in space to shoot down enemy missiles. Reagan was fascinated with this idea.

What Teller did not tell the President was that these x-ray lasers did not even exist in the laboratories and that the present concept for them required exploding an atomic bomb simply to provide the energy for the laser.

Needless to say, President Reagan ran with the idea.

Reagan's idea

President Reagan's idea was to set up a large number of space satellites that would detect the launch of an enemy missile and then shoot down that missile. Essentially, he wanted to form a protective shield against possible missile attacks from the Russians.


This was an almost impossible task, but if it worked it would change the balance of power. Previously, both the US and Russia followed the MAD (mutually acknowledged destruction) philosophy, where we would not attack because we both would be destroyed.

To make the Russians feel less threatened, he promised to give them the technology we developed, so they could have their own protective shield. Predictably, the Soviets did not believe Reagan.

Treaty problem

A major problem with pursuing the concept was that such an anti-missile defense in space was against existing treaties we had signed. It was possible to do research, but we could not actually test or employ the devices in space.

Research expensive

The research done on SDI was very expensive—costing us billions of dollars each year. Development was done on spy-in-the-sky satellites, space-based laser weapons and space-based interceptors. There was also research done on ground-based anti-missile missiles as a last resort if the space-based weapons missed their targets.

Difficult scenario

What made such a defensive scheme so difficult is the fact that the enemy would not simply send up one or two missiles in such an attack. Instead, they would send up a major part of their arsenal—hundreds, if not thousands of missiles—to try to completely destroy our offensive and defensive capabilities and eliminate our major cities.

Russians respond

In response to our research, the Russians worked on developing their own version of SDI. Likewise, it also cost them a large amount of money, above and beyond their normal defense spending.

This extra expenditure helped to weaken the Soviet Union's economy.

New American outlook

It became apparent to those working on SDI that although the technology to effectively protect against enemy missiles was years and billions of dollars away, the cost to the Soviets was even more. The economy of the USSR was not as robust as the American economy, so they could ill-afford to spend so much on the develop of such a system.

Thus, a new outlook toward SDI arose. Besides defending against possible missile attacks, SDI could also be used as an economic weapon to help cripple the Soviet economy.

Press criticized program

The U.S. press continually criticized the program as too expensive and not feasible. Unfortunately, they did not realize or were blind to the fact that SDI was now an economic weapon.

SDI helps downfall of Soviets

SDI ultimately proved very successful, since it was instrumental in causing the downfall of the Soviet Union. After the USSR (Union of Soviet Socialist Republics) was disbanded and Communism was discontinued, Russian officials admitted that SDI was the reason. Little was said about this in the American press.

Continuation of SDI

Since there was no longer a reason for SDI, Congress cancelled the program in the early 90s. Air Force then changed the name of the program and continued its research. The press never followed up on this and moved on to other issues.

The continuation of the SDI research was like many military projects that go on, even if there is no threat. Although now, with some 3rd World countries possessing atomic weapons and missile systems, perhaps it is worthwhile to still try to protect against such an attack.


The Strategic Defense Initiative (SDI) was an attempt to put a defensive shield around the United States to protect against Soviet missile attacks. The Russians spent so much money trying to counter this shield, that it contributed to the downfall of the Soviet system.

Lessons learned from studying SDI are:

You can sometimes win without defeating the opponent

Resources and references

Ron Kurtus' Credentials


Federation of American Scientists articles on Strategic Defense Initiative

History of the Missile Defense Organization - U.S. Department of Defense

SDI History Resources


(Notice: The School for Champions may earn commissions from book purchases)

Secret Weapons of the Cold War: From the H-Bomb to SDI by William Yenne; Berkley (2005) $7.99

US Strategic And Defensive Missile Systems 1950-2004 by Mark A. Berhow, Chris Taylor; Osprey Books (2005) $16.95

Top-rated books on Missle Defense

Students and researchers:

The Web address of this page is:

Please include it as a link on your website or as a reference in your report, document, or thesis.

Copyright © Restrictions

Where are you now?

School for Champions

Strategic Defense Initiative topics

Overview of the Strategic Defense Initiative (SDI)

SDI topics

Development of SDI

Total Quality Management in SDI

Also see:

Live Your Life as a Champion:

Take care of your health

Seek knowledge and gain skills

Do excellent work

Be valuable to others

Have utmost character

Be a Champion!

The School for Champions helps you become the type of person who can be called a Champion.