Minuteman / Peacekeeper Launch Facility P-04 (Papa-04 LF), Hillsdale Wyoming

P-04 was one of the places where the Cold War narrowed to a square of fenced ground on the Wyoming plains. To a passerby north of Hillsdale, it would not have looked like a strategic landmark. Its purpose was underground: first as a Minuteman launch facility in F.E. Warren's dispersed missile field, and later as one of the 50 former Minuteman silos rebuilt to hold the LGM-118A Peacekeeper, the largest and most controversial ICBM ever placed on operational alert in the United States.

P-04 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, near Hillsdale.

P-04 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-04 lay in the agricultural and ranching country north of Hillsdale and northeast of F.E. Warren Air Force Base. Like the other Papa Flight launch facilities, it was deliberately separated from the crewed Papa One control site and from neighboring silos. That spacing was not incidental landscape planning. It was part of the basic Minuteman and Peacekeeper logic: each launch facility had to be far enough from others that a single attack could not easily destroy a whole flight.

As a Minuteman/Peacekeeper launch facility, P-04 would have been normally unmanned. Missile combat crews served at the underground launch-control center associated with P-01, while maintenance, communications, and security teams visited P-04 as needed. The surface site would have included the typical launch-facility features: access road, security fencing, launcher closure, personnel-access features, underground launcher and support equipment, power and communications connections, and hardstand/apron features. The site's exact post-elimination surface condition is not known.

Site History

P-04 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-04 belonged to that 400th Squadron group, later identified with the P-through-T Peacekeeper conversion.

During its first operational era, P-04 held a solid-fueled Minuteman missile rather than one of the earlier liquid-fueled Atlas missiles that had made F.E. Warren the first operational U.S. ICBM base. That difference mattered. Minuteman could remain in a hardened underground silo and respond far more quickly than the earlier Atlas systems. For a remote launch facility like P-04, this meant its daily role was largely silent: monitored from the LCC, maintained by specialized crews, guarded as needed, and kept ready as one part of a much larger deterrent system.

F.E. Warren's original Minuteman force used LGM-30B Minuteman I missiles. In the 1970s, the wing implemented SAC's Force Modernization Program and replaced the 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-04 therefore represents both the original Minuteman I deployment and the later Minuteman III modernization of the F.E. Warren field.

The site's second and more distinctive life came with Peacekeeper. The missile began as the MX, or Missile Experimental, during a long and politically charged debate over how to base a new, more powerful ICBM without making it vulnerable. The United States considered multiple basing ideas, including rail-mobile concepts and more elaborate schemes in the West. The eventual operational solution was less exotic but still consequential: placing 50 Peacekeepers into modified former Minuteman silos at F.E. Warren, directly north of Cheyenne and across the same general Wyoming missile landscape that included P-04.

Peacekeeper was not simply a new missile in an old hole. The LGM-118A was a four-stage missile that used a cold-launch method. Public Air Force and National Park Service sources describe the method as ejecting the missile from a modified Minuteman silo with high-pressure steam before the first-stage solid rocket motor ignited after the missile cleared the silo. The missile was far larger and heavier than Minuteman, and public Air Force data describes it as roughly 71 feet tall, about 195,000 pounds, with inertial guidance, a range greater than 6,000 miles, and a payload of up to ten Avco MK-21 reentry vehicles. The conversion of P-04 and the other P-through-T launch facilities therefore represented a major physical and operational transformation of the former Minuteman infrastructure.

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, public Air Force sources state that 50 Peacekeeper missiles were in service at F.E. Warren. P-04 was one of those former Minuteman launch facilities in the 400th Missile Squadron's 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 deactivation 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.

Current Status and Site Use

After Peacekeeper deactivation, P-04 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 the 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 under New START the launch facilities had to remain visible for inspection and verification during dismantlement and for a post-dismantlement verification period.

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

• 1963-02-21 SAC redesignated the 90th Strategic Reconnaissance Wing as the 90th Strategic Missile Wing.
• 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-04 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-04 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.
• 2013-08-23 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