Minuteman Launch Facility P-11 (Papa-11 LF), Hillsdale Wyoming

P-11 was the last launch facility in Papa Flight, the northern end of a ten-silo chain that began with P-01 and spread across the Wyoming high plains. On the surface, it was a fenced utility compound in open ranch country. Underground, it belonged to one of the more unusual chapters in American ICBM history: a former Minuteman silo rebuilt for the LGM-118A Peacekeeper, the Cold War missile that carried the MX basing debate from national controversy into fifty modified silos north of Cheyenne.

P-11 was a Launch Facility / LF in Papa Flight, F.E. Warren Air Force Base missile field. It was associated with P-01 Missile Alert Facility / Launch Control Center and the 400th Strategic Missile Squadron, later the 400th Missile Squadron, under the 90th Strategic Missile Wing / 90th Missile Wing. The site was originally part of F.E. Warren's LGM-30B Minuteman I force, later served in the LGM-30G Minuteman III era, and was then converted for the LGM-118A Peacekeeper. The site is in Laramie County, Wyoming, about 25.4 miles north-northwest of Hillsdale

P-11 is inactive and decommissioned. It is no longer an operational launch facility. No public access to the former launch-facility property was verified.

Site Location and Physical Description

P-11 lay in Laramie County, Wyoming, northwest of Hillsdale and northeast of F.E. Warren Air Force Base. Within Papa Flight, it was the northernmost numbered launch facility and helped define the outer edge of the P-01 control group before the field transitioned westward toward the Quebec Flight area and northward toward Romeo and Sierra/Tango geography. The surrounding landscape is high-plains ranch and agricultural country, with open grassland, low rolling ground, fence lines, isolated roads, and long sightlines across the former missile field.

As with other Minuteman and Peacekeeper launch facilities, P-11 was normally unmanned. The missile combat crew served in the underground launch-control center associated with P-01, while maintenance, communications, and security forces visited the launch facility as required. The surface site would have included the normal features of a hardened LF: an access road, perimeter security fencing, a launcher closure, personnel-access features, underground launcher and support equipment, communications and power connections, and vehicle hardstand or apron features.

P-11 has useful visible-condition documentation from a non-official August 2013 photographic survey, near the beginning of the New START elimination period. The listing recorded six general views and two silo-area views. The photographs show a fenced compound in open grassland with visible launcher-area structures, security fencing, lighting or utility poles, and remaining surface features. Those photographs document what the site looked like in August 2013, but they should not be treated as proof of the present surface condition after New START elimination, grading, transfer, sale, or reuse.

Site History

P-11 was constructed as part of the F.E. Warren Minuteman missile field, a 200-missile deployment spread across Wyoming, Nebraska, and Colorado. The 90th Strategic Missile Wing was activated at F.E. Warren on 1 July 1963. The 400th Strategic Missile Squadron was organized in 1964, and public wing history states that the 90th SMW placed its 200th Minuteman missile on alert on 15 June 1965, becoming the first fully operational Minuteman wing. P-11 belonged to the 400th Squadron group later converted for Peacekeeper service.

The original missile context at P-11 was LGM-30B Minuteman I. F.E. Warren's Minuteman deployment differed sharply from the earlier Atlas era at the same base. Atlas had been liquid-fueled, maintenance-intensive, and tied to an earlier generation of ICBM technology. Minuteman was solid-fueled, stored in a hardened underground launcher, and built for rapid response from dispersed sites. For an individual launch facility like P-11, that meant a mostly unseen operational life: remote monitoring from the LCC, periodic maintenance, security response readiness, and continuous integration into a larger strategic-alert network.

F.E. Warren's Minuteman force was later modernized. In the 1970s, the wing implemented SAC's Force Modernization Program and replaced Minuteman IB with the LGM-30G Minuteman III. The 400th Strategic Missile Squadron became the wing's first all-Minuteman III squadron in 1973, and the 90th SMW removed its last Minuteman IB from alert on 3 September 1974. P-11 therefore represents both the original Minuteman I deployment and the later Minuteman III modernization of the F.E. Warren field. Minuteman II was not deployed at F.E. Warren.

The site's second operational life came with Peacekeeper. The missile began as MX, or Missile Experimental, in the early 1970s and became one of the most controversial strategic weapons programs of the late Cold War. The Air Force and national policymakers considered multiple basing approaches, including mobile and hardened concepts, before settling on deployment in modified Minuteman silos at F.E. Warren. That decision made the P-through-T flights of the 400th Missile Squadron the only operational Peacekeeper silo field in the United States.

Peacekeeper was not simply another Minuteman variant. Public Air Force sources describe the LGM-118A as a four-stage missile and the first Air Force ICBM to use a cold-launch method. In that system, high-pressure steam ejected the missile from a modified Minuteman underground silo before the first-stage solid rocket motor ignited after the missile cleared the silo. Public data describes Peacekeeper as roughly 71 feet tall, about 195,000 pounds, inertially guided, with a range greater than 6,000 miles, and a payload of up to ten Avco MK-21 reentry vehicles. The conversion of P-11 and its companion sites therefore turned former Minuteman infrastructure into a much larger and more technically demanding missile system.

The 90th Strategic Missile Wing had its first strategically postured Peacekeeper site on 10 October 1986 and reached initial operating capability for the system on 16 December 1986. By 1988, Air Force sources state that 50 Peacekeeper missiles were in service at F.E. Warren. P-11 was one of the former Minuteman launch facilities in the 400th Missile Squadron's converted Peacekeeper group.

The Peacekeeper era ended in stages. U.S. and Russian nuclear agreements in the early 2000s, budget decisions, and the changed post-Cold War strategic environment led to phased Peacekeeper deactivation beginning in 2002. F.E. Warren wing history states that the 90th Space Wing completed deactivation of the last Peacekeeper ICBM on 14 September 2005, and an Air Force account of the 19 September 2005 ceremony states that a missile combat crew officer at Papa One Launch Control Center confirmed that no Peacekeeper ICBMs remained on strategic alert in the 400th Missile Squadron. No P-11-specific missile-removal date was located, so 2005-09-19 is used as the documented end point for the Peacekeeper alert mission associated with Papa Flight and the 400th MS.

Current Status and Site Use

After Peacekeeper deactivation, P-11 became part of the broader New START silo-elimination program. A 2011 Federal Register public-inspection notice stated that New START required the Air Force to dismantle 103 non-operational launch facilities, including 50 Peacekeeper launch facilities of the deactivated 400th Missile Squadron and five associated missile alert facilities at F.E. Warren. The same notice identified possible dismantlement methods including implosion, excavation, and backfill, with complete dismantlement required by 4 February 2018.

AFCEC announced in 2013 that the Air Force had released the final environmental assessment and draft finding of no significant impact for dismantling deactivated ICBM facilities. The AFCEC release explained that the silos had to be dismantled in a way that ensured they could no longer be used as missile launch facilities, and that the associated missile alert facilities were also analyzed because they would serve no useful purpose after the silos were dismantled.

F.E. Warren announced in August 2013 that the U.S. government had chosen to permanently eliminate 50 previously deactivated F.E. Warren Peacekeeper launch facilities. The release stated that the U.S. Army Corps of Engineers and the Air Force Civil Engineer Center selected Bryan Construction, Inc. as demolition contractor, that the former Peacekeeper launch facilities north of Cheyenne were then planned for elimination by December 2014, and that the contractor would eliminate silos by filling them with earth and gravel. The release also stated that after the launch facilities were eliminated, the land would become available for purchase, beginning with adjacent landowners' right of first refusal.

For the full Papa Flight narrative, see P-01 Missile Alert Facility / Launch Control Center

Chronology

• 1963-07-01 The 90th Strategic Missile Wing was activated at F.E. Warren Air Force Base with the 319th, 320th, 321st, and 400th Strategic Missile Squadrons.
• 1964 The 400th Strategic Missile Squadron was organized at F.E. Warren; P-11 belonged to the squadron group later converted for Peacekeeper service.
• 1965-06-15 The 90th Strategic Missile Wing placed its 200th Minuteman missile on alert and became the first fully operational Minuteman wing.
• 1972 F.E. Warren began SAC's Force Modernization Program to replace Minuteman IB with Minuteman III.
• 1973 The 400th Strategic Missile Squadron became the first all-Minuteman III squadron in the 90th Strategic Missile Wing.
• 1974-09-03 The 90th Strategic Missile Wing removed its last Minuteman IB from alert status.
• 1982-11 President Ronald Reagan renamed the MX missile Peacekeeper.
• 1984-07 Peacekeeper support-facility construction began at F.E. Warren, according to public site-listing history.
• 1986-10-10 The 90th Strategic Missile Wing had its first strategically postured Peacekeeper site.
• 1986-12-16 The 90th Strategic Missile Wing reached initial operating capability for Peacekeeper.
• 1988 The Air Force had 50 Peacekeeper missiles in service at F.E. Warren; P-11 was one of the former Minuteman launch facilities in the converted 400th Missile Squadron group.
• 2005-09-14 The 90th Space Wing completed deactivation of the last of its Peacekeeper ICBMs, according to the F.E. Warren wing history.
• 2005-09-19 The Peacekeeper mission formally ended at F.E. Warren; a missile combat crew officer at Papa One Launch Control Center confirmed that no Peacekeeper ICBMs remained on strategic alert in the 400th Missile Squadron.
• 2005-10 The 400th Missile Squadron was deactivated after the end of the Peacekeeper mission.
• 2011-02-05 New START entered into force.
• 2011-11-17 The Air Force published notice of intent to prepare an environmental assessment for Minuteman III and Peacekeeper silo elimination/dismantlement, including 50 Peacekeeper launch facilities and five associated missile alert facilities at F.E. Warren.
• 2013-03-22 AFCEC announced the final environmental assessment and draft finding of no significant impact for dismantling deactivated Minuteman III and Peacekeeper launch facilities under New START.
• 2013-08-19 A non-official site-photo survey documented P-11 general views and silo-area features.
• 2013-08-23 F.E. Warren announced that 50 previously deactivated Peacekeeper launch facilities north of Cheyenne would be permanently eliminated under New START.
• 2014-12 F.E. Warren's 2013 release identified December 2014 as the planned completion point for eliminating the former Peacekeeper launch facilities north of Cheyenne.
• 2018-02-04 New START required complete dismantlement of covered launch facilities by this date.

Read about the Peacekeeper Missile at F.E. Warren AFB

All Peacekeeper Missile Silo Locations

All Minuteman/Peacekeeper Missile Silo Locations