Editing SM-65 Atlas (section)

==Operational deployment==
[[File:SM-65 Atlas Missile Sites.png|thumb|500px|SM-65 Atlas deployment sites: &nbsp;SM-65D (Red), SM-65E (Purple), SM-65F (Black)]]
[[Strategic Air Command]] deployed 13 operational Atlas ICBM squadrons between 1959 and 1962. Each of the three missile variants, the Atlas D, E, and F series, were deployed and based in progressively more secure launchers.<ref name="coldwarlegacy"/>{{rp|216}}

===Service history===
The number of Atlas intercontinental ballistic missiles in service, at the end of each year:<ref name="nrdcstrat"/>{{rp|Table 3}}<br/>

{| class=wikitable style="text-align:center"
|-
! Date
! CGM-16D<br/> (Atlas D)
! CGM-16E<br/> (Atlas E)
! HGM-16F<br/> (Atlas F)
|-
| 1959||  6|| 0|| 0
|-
| 1960|| 12|| 0|| 0
|-
| 1961|| 30||27|| 0
|-
| 1962|| 30||27|| 72
|-
| 1963|| 20||27|| 72
|-
| 1964||  0|| 0|| 72
|}

===Atlas-D deployment===
[[Image:Atlas-icbm-erection-large.jpg|thumb|Atlas-D ICBM launching from semi-hardened "coffin" bunker at Vandenberg AFB, California.]]
In September 1959 the first operational Atlas ICBM squadron went on operational alert at [[F.E. Warren AFB]],<ref name="AtlD">{{cite web |url=http://www.siloworld.net/ICBM/ATLAS/ATD/location2.htm |title=Atlas D Locations |website=siloworld.net |archive-url=https://web.archive.org/web/20220713171215/http://www.siloworld.net/ICBM/ATLAS/ATD/location2.htm |archive-date=13 July 2022}}</ref> Wyoming equipped with six [[SM-65D Atlas]] missiles based in above-ground launchers.  Three additional Atlas D squadrons, two near F.E. Warren AFB, Wyoming, and one at [[Offutt AFB]], Nebraska,<ref name="AtlD"/> were based in above-ground launchers that provided blast protection against over-pressures of only {{convert|5|psi}}.
These units were:
* [[389th Strategic Missile Wing]]
: [[Francis E. Warren AFB]], [[Wyoming]] (2 September 1960 – 1 July 1964)
: [[564th Strategic Missile Squadron]] (6 missiles)
: [[565th Strategic Missile Squadron]] (9 missiles)

* [[385th Strategic Aerospace Wing|385th Bombardment (later Strategic Aerospace) Wing]]
: [[Offutt AFB]], [[Nebraska]] (30 March 1961 – 1 October 1964)
: [[549th Strategic Missile Squadron]] (9 missiles)

The first site at Warren for the 564th SMS consisted of six launchers grouped together, controlled by two launch operations buildings, and clustered around a central guidance control facility. This was called the 3&nbsp;×&nbsp;2 configuration: two launch complexes of three missiles each constituted a squadron.<ref name="coldwarlegacy">{{cite report|title=To Defend and Deter: The Legacy of the United States Cold War Missile Program|author1=John C. Lonnquest |author2=David F. Winkler|date=November 1996
|url=https://apps.dtic.mil/sti/pdfs/ADA337549.pdf |archive-url=https://web.archive.org/web/20201020041232/https://apps.dtic.mil/sti/pdfs/ADA337549.pdf |archive-date=2020-10-20 |url-status=live|website=dtic.mil|publisher=Department of Defense Legacy Resource Management Program Cold War Project|access-date=March 12, 2023}}</ref>{{rp|218}}

At the second Warren site for the 565th SMS and at Offutt AFB, Nebraska, for the 549th SMS, the missiles were based in a 3 x 3 configuration: three launchers and one combined guidance control/launch facility constituted a launch complex, and three complexes comprised a squadron. At these later sites the combined guidance and control facility measured {{convert|107|by|121|ft|0|abbr=on}} with a partial basement.  A dispersal technique of spreading the launch complexes were {{convert|20|to|30|mi|-1}} apart was also employed to reduce the risk that one powerful nuclear warhead could destroy multiple launch sites.<ref name="coldwarlegacy"/>

===Atlas-E deployment===
The SM-65E Atlas were based in horizontal "semi-hard" or "coffin" facilities that protected the missile against over-pressures up to {{convert|25|psi|abbr=on}}. In this arrangement the missile, its support facilities, and the launch operations building were housed in reinforced concrete structures that were buried underground; only the roofs protruded above ground level. These units were:<ref name="AtlE">{{cite web |url=http://www.siloworld.net/ICBM/ATLAS/ATE/location3.htm |title=Atlas E Locations |website=siloworld.net |archive-url=https://web.archive.org/web/20220714124029/http://www.siloworld.net/ICBM/ATLAS/ATE/location3.htm |archive-date=14 July 2022 |url-status=live}}</ref>
* [[92d Bombardment Wing|92nd Bombardment (later Strategic Aerospace) Wing]]
: [[Fairchild Air Force Base]], [[Washington (state)|Washington]] (28 September 1961 – 17 February 1965)
: [[567th Strategic Missile Squadron]], (9 missiles)

* [[21st Strategic Aerospace Division]]
: [[Forbes AFB]], [[Kansas]] (10 October 1961 – 4 January 1965)
: [[548th Strategic Missile Squadron]], (9 missiles)

* [[389th Strategic Missile Wing]]
: [[Francis E. Warren AFB]], [[Wyoming]] (20 November 1961 – 4 January 1965)
: [[566th Strategic Missile Squadron]] (9 missiles)

===Atlas-F deployment===
The six [[SM-65F Atlas]] squadrons were the first ICBMs to be stored vertically in underground silos. Built of heavily reinforced concrete, the huge silos were designed to protect the missiles from over-pressures of up to {{convert|100|psi|abbr=on}}.<ref name="armycoe">{{cite web|title=Historical Vignette 032 - The Corps Built the Launch Sites for Atlas ICBM|date=August 2001 |url=https://www.usace.army.mil/About/History/Historical-Vignettes/Military-Construction-Combat/032-Atlas-ICBM/|publisher=U.S. Army Corps of Engineers|access-date=March 11, 2023}}</ref> These units were:<ref name="AtlF">{{cite web |url=http://www.siloworld.net/ICBM/ATLAS/ATF/LOCATION.HTM |title=Atlas F Locations |website=siloworld.net |archive-url=https://web.archive.org/web/20201112045023/http://www.siloworld.net/ICBM/ATLAS/ATF/LOCATION.HTM |archive-date=12 November 2020 |url-status=live}}</ref>
{{Col-begin}}
{{Col-break|width=50%}}
* [[310th Strategic Aerospace Wing|310th Bombardment (later Strategic Aerospace) Wing]]
: [[Schilling AFB]], [[Kansas]] (9 September 1962 – 1 February 1965)
: [[550th Strategic Missile Squadron]] (12 missiles)

* [[98th Strategic Aerospace Wing]]
: [[Lincoln AFB]], [[Nebraska]] (15 September 1962 – 10 March 1965)
: [[551st Strategic Missile Squadron]] (12 missiles)

* [[11th Wing|11th Bombardment (later Strategic Aerospace) Wing]]
: [[Altus AFB]], [[Oklahoma]] (9 October 1962 – 30 December 1964)
: [[577th Strategic Missile Squadron]] (12 missiles)

{{Col-break|width=50%}}
* [[96th Air Base Wing|96th Bombardment (later Strategic Aerospace) Wing]]
: [[Dyess AFB]], [[Texas]] (15 November 1962 – 1 December 1964)
: [[578th Strategic Missile Squadron]] (12 missiles)

* [[6th Air Mobility Wing|6th Bombardment (later Strategic Aerospace) Wing]]
: [[Walker AFB]], [[New Mexico]] (30 November 1962 – 5 January 1965)
: [[579th Strategic Missile Squadron]] (12 missiles)

* [[820th Strategic Aerospace Division|820th Air (later Strategic Aerospace) Division]]
: [[Plattsburgh AFB]], [[New York (state)|New York]] (20 December 1962 – 12 March 1965)
: [[556th Strategic Missile Squadron]] (12 missiles)
{{col-end}}
The Atlas F's employment was dangerous due to the flammability of the stored liquid rocket fuels.  Four sites and their missiles were destroyed during propellant loading exercises (known as PLXs) when liquid oxygen leaked and fires ensued.  On 1 June 1963 Roswell's site 579-1 was destroyed by explosion and fire.  On 13 February 1964 Roswell's site 579-5 was destroyed, and a month later on 9 March 1964 site 579-2 was also destroyed by explosion and fire.  Finally, on 14 May 1964 an Altus AFB site, 577-6 in Frederick, Oklahoma, was also destroyed by explosion and fire during a PLX.  Fortunately the crews all survived.  None of the damaged sites were repaired or returned to service.  

===Retirement as an ICBM===
After the [[Solid-fuel rocket|solid-fuel]] [[LGM-30 Minuteman]] had become operational in early 1963, the Atlas became rapidly obsolete.<ref>{{cite web|title=Air Force history of ICBM development, safeguarding America
|date=March 5, 2012|author=Reggie Manning|url=https://www.afgsc.af.mil/News/Features/Display/Article/455710/air-force-history-of-icbm-development-safeguarding-america/|website=U.S. Air Force|access-date=March 11, 2023}}</ref> By October 1964, all Atlas D missiles had been phased out, followed by the Atlas E/F in April 1965. About 350 Atlas ICBMs of all versions were built, with a peak deployment level of 129 (30 D, 27 E, 72 F). Despite its relatively short life span, Atlas served as the proving ground for many new missile technologies. Perhaps more importantly, its development spawned the organization, policies, and procedures that paved the way for all of the later ICBM programs.<ref>{{cite web |author=Parsch, Andreas |title=Directory of U.S. Military Rockets and Missiles - Convair B-65/SM-65/CGM-16/HGM-16 Atlas |url=https://www.designation-systems.net/dusrm/m-16.html |archive-url=https://web.archive.org/web/20021003044253/http://www.designation-systems.net/dusrm/m-16.html |archive-date=3 October 2002 |url-status=live}}</ref>

After its retirement from operational ICBM service in 1965, the ICBMs were refurbished and used for close to forty years as space launch vehicle boosters.<ref name="csisatlas"/>