Editing Strategic Defense Initiative (section)

==Project and proposals==
[[File:Reagan SDI Speech 1983.ogv|thumb|right|President Reagan delivering the March 23, 1983, speech initiating SDI]]

=== Announcement ===
On March 23, 1983, Reagan announced SDI in a nationally televised speech, stating "I call upon the scientific community in this country, those who gave us nuclear weapons, to turn their great talents to the cause of mankind and world peace, to give us the means of rendering these nuclear weapons impotent and obsolete."<ref>{{cite web| url = https://www.reaganlibrary.gov/archives/speech/address-nation-defense-and-national-security| title = "Address to the Nation on Defense and National Security", March 23, 1983}}</ref>

=== Strategic Defense Initiative Organization (SDIO) ===
In 1984, the Strategic Defense Initiative Organization (SDIO) was established to oversee the program, which was headed by Lt. General [[James Alan Abrahamson]] USAF, a past Director of the [[Space Shuttle program]].<ref name="fas_milestones" />

In addition to original Heritage ideas, other concepts were considered. Notable among these were [[particle-beam weapon]]s, updated versions of [[nuclear shaped charge]]s, and various [[Directed-energy weapon|plasma weapons]]. SDIO invested in computer systems, component miniaturization, and sensors.

Initially, the program focused on large-scale systems designed to defeat a massive Soviet offensive strike. For this mission, SDIO concentrated almost entirely on "high tech" solutions like lasers. Graham's proposal was repeatedly rejected by members of the Heritage group as well as within SDIO; when asked about it in 1985, Abrahamson suggested that the concept was underdeveloped and was not considered.

By 1986, many of the promising ideas were failing. Teller's X-ray laser, run under [[Project Excalibur]], failed several key tests in 1986 and was targeted to the anti-satellite role. The particle beam concept was demonstrated to basically not work, as was the case with several other concepts. Only the Space-Based Laser seemed to have any hope of developing in the short term, but it was growing in size due to its fuel consumption.

=== APS report ===
The [[American Physical Society]] (APS) had been asked by SDIO to provide a review of the various concepts. They put together an all-star panel including many of the inventors of the laser, including a [[Nobel laureate]]. Their initial report was presented in 1986, but was released to the public (in redacted form) in early 1987.<ref name=APS>{{cite tech report |url=http://digitalcollections.library.cmu.edu/awweb/awarchive?type=file&item=710809 |title=The Science and Technology of Directed Energy Weapons |publisher=APS |date=April 1986}}</ref>

The report considered all of the systems then under development and concluded none of them were anywhere near ready for deployment. Specifically, they noted that all of the systems had to improve their energy output by at least 100 times, and in some cases by as much as a million. In other cases, like Excalibur, they dismissed the concept entirely. Their summary stated simply:

<blockquote>We estimate that all existing candidates for directed energy weapons (DEWs) require two or more orders of magnitude, (powers of 10) improvements in power output and beam quality before they may be seriously considered for application in ballistic missile defense systems.<ref name=APS/></blockquote>

They concluded that none of the systems could be deployed as an anti-missile system until the next century.<ref name=APS/>

===Strategic Defense System===
Faced with this report and accompanying negative press, SDIO changed direction. Beginning in late 1986, Abrahamson proposed that SDI would be based on the system he had previously dismissed, a version of High Frontier now named the "Strategic Defense System, Phase I Architecture". The name implied that the concept would be replaced by more advanced systems in future phases.

Strategic Defense System (SDS) was the low-earth orbit (LEO) [[Smart Rocks]] concept with an added layer of ground-based missiles sited in the US. These missiles were intended to attack warheads that the Smart Rocks missed. In order to track them below the [[radar horizon]], SDS added more LEO satellites that would feed tracking information to both the space-based "garages" as well as the ground-based missiles.<ref>{{Cite web |access-date=2024-07-05 |website=U.S. Department of Defense |language=en-US|author=Missile Defense Agency |authorlink=Missile Defense Agency |url=http://www.defenselink.mil/specials/missiledefense/history.html |title=History of the Missile Defense Organization}}</ref> Later [[Ground-Based Midcourse Defense|ground-based systems]] trace derived from this concept.

LLNL then introduced the [[Brilliant Pebbles]] concept. This was essentially the combination of the sensors on the garage satellites and the tracking stations. Advancements in sensors and [[microprocessors]] allowed this to be packaged in a small missile nose cone. Subsequent studies suggested that this approach would be cheaper, easier to launch and more resistant to counterattack, and in 1990 Brilliant Pebbles was selected as the baseline model for SDS Phase 1.

=== Global Protection Against Limited Strikes ===
While SDIO pursued SDS, the [[Warsaw Pact]] was rapidly disintegrating, culminating in the destruction of the [[Berlin Wall]] in 1989. One of the many reports on SDS considered these events and suggested that a massive defense against a Soviet launch would become unnecessary. However, short and medium range missile technology would likely proliferate as the Soviet Union disintegrated and sold off its hardware. One of the core ideas behind Global Protection Against Limited Strikes (GPALS) was that the Soviet Union would not always be the aggressor and the United States would not always be the target.<ref name=":0" />

Instead of a heavy defense aimed at ICBMs, this report suggested realigning GPALS deployment. Against novel threats the [[Brilliant Pebbles]] would have limited utility, largely because the missiles fired for only a short period and the warheads did not rise high enough for them to be easily tracked by a satellite above them. GPALS thus added a mobile ground-based missile and more low-orbit satellites known as [[Brilliant Eyes]] to feed the Pebbles.

GPALS was approved by [[George H. W. Bush|President George H.W. Bush]] in 1991.<ref name=":0">{{Cite book|title=The Militarization and Weaponization of Space (1st ed.)|last=Mowthorpe|first=Matthew|publisher=Lexington Books|year=2004|location=New York}}</ref> The system would cut the proposed costs of the SDI system from $53&nbsp;billion to $41&nbsp;billion over a decade.<ref name=":0" /> Instead of attempting to protect against thousands of incoming missiles, GPALS sought to provide protection from up to two hundred nuclear missiles.<ref name=":1">{{Cite magazine|last=Morrison|first=David|year=1992|title=Starburst|magazine=The New Republic|volume=206|pages=21–23}}</ref> GPALS was tasked to protect the United States from attacks coming from all different parts of the world.<ref name=":1" />

=== Ballistic Missile Defense Organization (BMDO) ===
{{main|Ballistic Missile Defense Organization}}

In 1993, the [[Clinton administration]] further shifted the focus to ground-based interceptor missiles and theater-scale systems, renaming the SDIO to the [[Ballistic Missile Defense Organization]] (BMDO).<ref>{{Cite web |title=SDIO Changes Its Letterhead To BMDO |url=https://www.bits.des |last=Raikow |first=David |date=June 1993 |publisher=Arms Control Today}}</ref>

In 2002, the [[George W. Bush administration]] in turn renamed the BMDO to the [[Missile Defense Agency]] (MDA), indicating plans for a layered missile defence system that integrates different types of defences, including sea- and ground-based defences.<ref>{{Cite press release |title=BMDO Renamed 'Missile Defense Agency' |date=January 2002 |publisher=Arms Control Association |url=https://www.armscontrol.org/act/2002-01/press-releases/bmdo-renamed-missile-defense-agency |access-date=2025-01-29 |location=Washington, D.C. |last1=Boese |first1=Wade}}</ref>