Major Locales of the Titan I Complex

| Portal | Main Tunnel Junction | Control Center | Power House | Antenna Terminal |

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Portal Part I

The entry portal, gateway to the entire Titan I underground complex, is a vertical reinforced concrete cylinder 27 feet in diameter and 75' 2" from the top to the outside of the bottom slab comprising the portal floor.  The open interior is 69' 2" from grade to the floor making the bottom concrete slab 6 feet thick.

Side view of the portal silo showing the silo doors, crew entrance, spiral staircase and the portal stairs descending around the freight elevator cage to the bottom of the portal.

The silo itself has 2 massive doors each roughly 9'x11' and 3'6" thick protecting the complex from the terrific forces of a nuclear attack.  Each door opens with 2 powerful hydraulic rams which allows a 4 ton capacity freight elevator, approximately 10'x10' to rise to the surface.  The elevator carried equipment and supplies too large for the stairs into the complex and allowed for removal of refuse and other material from the site without the terrible burden of lugging them up 7 stories of staircase.  Whew!


The elevator cage occupies the center or the portal silo and is enclosed in heavy wire mesh.  About the elevator shaft the narrow stairway and landings slowly twist their way down to the bottom.


Side view of the portal showing the blast wall and doors at the bottom of the portal and the connecting passage to tunnel junction #10.


Detail of the silo doors and associated structures including the hydraulic system and rams that opened them.


The concrete around the perimeter and the doors themselves contains embedded copper tubing through which heated ethylene glycol is circulated during cold weather to prevent snow and ice build-up and to keep the doors from freezing shut.


There were several other openings at the surface of the portal aside from the giant silo doors.  The first of these was of course the personnel access where crews entered and exited the complex.  Two other openings were for a television camera and for an instrument array.


A cutaway view of the Portal silo showing the silo doors, television camera and instrument mount access tunnels (upper right), elevator cage and stairs.  The smaller round hatch to the left of the doors is the original personnel entrance-- a hatch 4.5 feet in diameter leading to a spiral staircase.


The television camera was for viewing the silo doors and any personnel arriving at the site and allowed surface activity to be remotely monitored from the control center-- an invaluable asset to an underground installation!


The instrument array measured surface conditions such as temperature and wind speed and detected radiation levels and blast waves.  It consisted of 4 flat-topped tubes that rose about 7 feet out of the ground.


Simplified top-down cross-section of the portal silo and its structures showing the personnel entrance on the right and the access tunnels and locations of the instrument array (left center) and the television camera (lower left).


Both of these assemblies are protected underground when not in use in their own small silos and are raised pneumatically from below ground when needed.


Side view of the television camera assembly and its tiny protective silo with a concrete and steel cap about 6' in diameter.  The "silo" itself is 5' in diameter and 22' deep with a 3' diameter tunnel connecting to the interior of the portal silo for air lines, cabling and maintenance access.


This blueprint doesn't show it, but a camera was mounted in the top section in a spring-suspended cradle.  The camera allowed arriving crews and other site visitors to be identified and allowed the surface to be monitored to ensure silos doors were open, missiles were raised properly and any surface conditions or events.


Side view of the instrument array tube.  The array consisted of 4 separate tubes with flat caps, each with their own set of instruments and detectors.  These tubes would raise hydraulically in concert and stood around 7' tall when raised.


Crew access to the complex was through a series formidable barriers intended to repel both damaging blast waves as well as ground forces or intruders.


Arriving at the guard shack, visitors and relief crews are cleared with the control center before being allowed to pass through the perimeter fence.  When they arrived at the portal they were greeted by the 4'6" steel and concrete hatch covering the personnel entrance.

Cross-section of the very upper portion of the portal silo showing the entrance with its revolving blast door and the stairs and elevator.

Once the hydraulic hatch was opened, a tight spiral staircase only large enough for one person at a time was the next obstacle.  This constricting and enclosed space was no accident or oversight by the designers of the Titan I complex; it was an effective security measure.  Any assault made on the the complex would find this small entrance a deadly bottleneck if they dared enter through it.


Immediately after the stairs, the next obstacle is a heavy explosion-hardened revolving blast door.  The vestibule of this door is only large enough to accommodate 1 person at a time.  This was no place for claustrophobics; this area has a low ceiling and really only enough room for a man to turn around.


The original entrance to the site showing the spiral stairs and the revolving blast door (at right).


This cramped space is what is known as a man trap because of its cage-like design.  With the hatch closed, there would be no way out and no way forward.


Side view of the access hatch and opening mechanism


Authorized personnel would hear a click as a remotely-operated locking bolt was withdrawn allowing the blast door to rotate counter-clockwise.  Pressing a release lever, the entering crewman would be able to push the door 180 degrees and enter the portal silo before it would lock again.  A camera inside the portal greeted each crew member as they emerged from the revolving blast door.

Detail of the access portal and spiral stairs

Detail showing the spiral stairs and revolving blast door giving an idea of the cramped quarters that awaited crew members early in the entry of the complex.  Note that the ceiling here is less than 6'6"!


The process was repeated for each crew member until everyone had filed into the portal stairs.  The access hatch was sealed after them and they made their way to the bottom where they were met with another daunting physical barrier: a pair of 8'x8' steel blast doors.


The inner space of the portal also acts as a man trap.  Escape from the portal would be all but impossible physically once the doors were sealed.  As a matter of course, to maintain a hardened facility, the large blast doors would remain locked until the surface doors were secured.  In this way, a blast would be prevented from entering the main complex and causing damage that could render it unable to perform a launch.


A top-down cross section of the bottom of the portal silo showing the hardened wall around the blast doors and the vestibule to the main tunnel of the complex.


Should infiltrators ever gain entrance to the portal, there is little they could do from inside without passage through the blast doors.  They would be sitting ducks in the hardened concrete cage of the portal silo.


Once beyond this last protective barrier, the crew finally entered the inner sanctum and met with the crew they were relieving from duty and began the briefing for turnover of command and status known as changeover.


Upper left: front view of the blast doors from the portal; Upper right: side view of the blast doors; lower: top-down view of the blast doors.


Next: Entry Portal section II looks at the construction of the portal silo, or if you prefer, click below to choose another location near the entry portal, or to see the Main Map of the complex.


Current Location: Entry Portal part I

Power House Exhaust Power House Fuel Terminal Control Center Entry Portal Power House Air Intake Main Tunnel Junction Main Map

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