Minuteman Launch Facility S-07 (Sierra-07 LF), Hawk Springs Wyoming

From the road, S-07 could pass for a fenced utility compound on the Wyoming plains: a gravel approach, security fence, poles, and the low traces of a buried system. Its significance was underground. Launch Facility S-07 was one of the unmanned missile silos assigned to Sierra Flight, controlled from S-01, and it later became part of the 400th Missile Squadron's Peacekeeper force at F.E. Warren Air Force Base. The coordinate records place S-07 in Goshen County, Wyoming, near Hawk Springs. A public 90th Missile Wing / Peacekeeper site photo listing identifies the site as Francis E. Warren AF Missile Site S-07, PIN 9417, ILC GHZN.

S-07 began as part of F.E. Warren's Minuteman missile field and was later converted through the Minuteman III-to-Peacekeeper program. Its parent installation was F.E. Warren Air Force Base, near Cheyenne, Wyoming. Its parent wing was the 90th Strategic Missile Wing during the Strategic Air Command era, later the 90th Missile Wing. Its Peacekeeper-era squadron was the 400th Missile Squadron. The parent control site for the flight was S-01 Missile Alert Facility / Launch Control Center, the Sierra Flight command-and-support facility. S-07 is no longer an active missile facility. The Peacekeeper mission at F.E. Warren ended on 2005-09-19, and the former Peacekeeper launch facilities were later included in New START-era silo-elimination planning.

S-07 occupied a rural setting in southern Goshen County, Wyoming, southwest of the Hawk Springs area and within the broader F.E. Warren missile field that spread across eastern Wyoming, western Nebraska, and northern Colorado.

Like the other former Peacekeeper launch facilities, S-07 was an unmanned launch facility rather than a crewed command post. The missile combat crew served at the associated launch control center, while maintenance, communications, and security personnel visited launch facilities as required. Environmental documentation for the later Peacekeeper disposal program describes a Peacekeeper launch facility as a fenced site containing the underground launcher and buried launcher support building. The 2013 New START silo-elimination environmental assessment describes the former Peacekeeper launchers as modified Minuteman facilities with an underground launcher, launcher support building, security fencing, and hardened cable connections to the missile alert facility.

The F.E. Warren Minuteman field was created during the rapid shift from first-generation liquid-fueled ICBMs to smaller, solid-fueled missiles that could be stored in hardened, dispersed silos. F.E. Warren's early Minuteman force replaced Atlas missiles in the early 1960s. The official 90th Missile Wing history notes that the Minuteman III replaced Minuteman I at F.E. Warren in 1975 and that Minuteman II was never deployed there. S-07 belonged to that Minuteman-origin landscape: a dispersed silo tied to a launch-control network, not an isolated base of its own.

The site's most historically distinctive period came with the Peacekeeper conversion. In the 1980s, fifty former Minuteman III silos assigned to the 400th Missile Squadron were modified to hold the LGM-118A Peacekeeper. The official F.E. Warren account states that 50 Peacekeeper missiles were brought on alert in modified Minuteman III silos in 1988. The Peacekeeper was a solid-propellant ICBM using a cold-launch method and a multiple-reentry-vehicle payload. Public Air Force fact sheets describe it as a four-stage missile, approximately 71 feet high and about 195,000 pounds, with a range greater than 6,000 miles. Its public significance was not merely that it was newer than Minuteman; it was that it represented the late-Cold-War push for a more accurate, survivable, land-based ICBM within the existing F.E. Warren missile field.

The Peacekeeper force did not leave service all at once. Public Air Force history records that Peacekeeper deployment at F.E. Warren began with an initial operational capability in the mid-1980s, reached the full force of 50 missiles by 1988, and was deactivated between 2003 and 2005. The final Peacekeeper mission ceremony occurred on 2005-09-19, confirming the end of Peacekeeper strategic-alert duty at F.E. Warren.

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

Cronology

• 1963 - F.E. Warren's Minuteman missile-field buildup was underway as Atlas gave way to hardened, dispersed Minuteman launch facilities.
• 1965-06 - The Minuteman force at F.E. Warren was in the fully operational era; S-07 belonged to the Minuteman-origin Sierra Flight launch-facility network.
• 1975 - Minuteman III replaced Minuteman I at F.E. Warren; Minuteman II was not deployed at F.E. Warren.
• 1986 - The first Peacekeeper missiles became operational at F.E. Warren.
• 1988 - The full 50-missile Peacekeeper force was on alert in modified Minuteman III silos at F.E. Warren.
• 2003 - Peacekeeper deactivation began under the program that removed the missile from the operational force.
• 2005-09-19 - The Peacekeeper mission at F.E. Warren ended.
• 2007-06 - A Tank Closure Report for Launch Facility Sierra-7, F.E. Warren AFB, Wyoming, was listed in the 2013 silo-elimination environmental assessment bibliography.
• 2011-02-05 - New START entered into force, creating later elimination requirements for selected deactivated U.S. missile silos and associated alert facilities.
• 2013 - The Final Environmental Assessment for Minuteman III and Peacekeeper Silo Elimination addressed former Peacekeeper launch facilities and associated missile alert facilities at F.E. Warren.
• 2013-08-04 - Public general-view photographs of S-07 were published in the AirForceBase.net Peacekeeper field photo set.
• 2018-02-04 - New START required the covered silo-elimination work to be completed by this date.

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

All Peacekeeper Missile Silo Locations

All Minuteman/Peacekeeper Missile Silo Locations