Major Locales of the Titan I Complex

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Propellant Terminals

Propellant Terminal - Side aspect


Propellant Terminal - Top-down view


The propellant terminal is another cylindrical structure, 37'6" in diameter, 2 stories high with reinforced concrete walls 18" thick used to store liquid oxygen (LOX), liquid and gaseous nitrogen and helium as well as equipment for controlling the transfer of these gasses from their storage tanks to the missile and to support equipment.


The upper level contained the LOX, nitrogen and helium transfer panels, and the lower level contained a helium cooler and LOX sub cooler and various vacuum pumps for the coolers.  The whole terminal was filled with non-reactive stainless steel plumbing for transfer of the volatile liquids and gasses along with standard steel and other piping for compressed air and water.


Upper level - Each of the upright tanks in the illustrations are actually an array of 4, 6 or 7 gas cylinders


Lower level - The LOX sub-cooler and other storage tanks and piping occupied the lower level


The propellant terminal is connected to the missile silo by the LOX tunnel on the lower level and to the LOX bay containing the LOX storage tank on the upper level.  The LOX tunnel in turn is connected to the LOX loading and vent shaft that runs to the surface.


The LOX tunnel routed the LOX lines from the propellant terminal to the missile and its oxidizer tanks and also carried helium and nitrogen to the silo and the missile.


The LOX bay contained the double-walled stainless steel LOX tank suspended in a giant steel cradle designed to attenuate the transfer of ground shocks to the pressurized vessel containing the thousands of gallons (each tank had a capacity of 28,000 gallons) of oxidizer for that particular launcher silo.


One of the launcher areas under construction prior to backfilling.  The propellant terminal in the foreground with the launcher silo in back and the equipment terminal in the upper right.  


Note the thickness of the concrete roof visible at the circular access portal.



View of the propellant terminal with the LOX bay visible on the left.  The LOX tank and connections can also be seen here.  At this stage the interconnecting tunnels to the launcher area have yet to be installed.

Photo courtesy of Fred Epler



Spring suspension mounts to support the propellant terminal floors.  Everything had to be able to withstand shock or a disastrous failure could occur.  The entire two-story structure was "floated" on these springs.

Photo courtesy of Fred Epler


It was paramount that the propellant systems not be damaged both to ensure launch capability and to avoid catastrophic fires and explosions that could render the entire complex unusable.


There was no greater threat to alert status and crew life and limb than the propellants that drove the rocket motors.  Even the warheads were a far lesser hazard-- they were so sufficiently safeguarded that an accidental detonation was unlikely even if the missile itself exploded.


Fun Facts About Modern Rocket Propellants

I find it interesting that the Titan II, which replaced the Titan I and all the existing Atlas configurations at the time, was actually far more hazardous in terms of the propellants used.  Aerozine 50 and (50% unsymmetrical dimethylhydrazine and 50% hydrazine) and nitrogen tetroxide are hypergolic propellants, which means that they spontaneously ignite when mixed.  This is great inside of a rocket motor-- not so great pretty much everywhere else.


Both nitrogen tetroxide and the components of Aerozine 50 are highly bio-hazardous and toxic: 


Unsymmetrical dimethylhydrazine (UDMH, C2H8N2):

  • Highly flammable and highly explosive

  • Highly corrosive

  • Forms other toxic compounds when burned

  • Evaporates easily at room temperature

  • Easily absorbed through skin, eyes and lungs

  • Attacks the central nervous system, liver and lungs

  • Causes respiratory failure, liver impairment and death

  • Carcinogenic

  • Hazardous to the environment


Hydrazine (N2H4):

  • Highly explosive and flammable

  • Reactive with moisture

  • Forms other toxic compounds when it breaks down

  • Can be fatal with severe exposure

  • Highly irritating if inhaled

  • Can be absorbed through skin

  • Corrosive to skin

  • Carcinogenic

  • Attacks the blood, kidneys, lungs, mucus membranes and central nervous system

  • Damages organs with repeated exposure


Dinitrogen Tetroxide (N2O4):

  • May spontaneously ignite combustible materials

  • Reacts with water to form corrosive acids

  • Reacts with metals in the presence of water to form highly flammable hydrogen gas

  • Highly toxic if inhaled

  • Corrosive to skin, eyes and respiratory tract

  • Can cause fatal pulmonary edema

  • Accelerates combustion

  • Hazardous to the environment


These propellants are still in use in one form or another today in both domestic and foreign liquid-fueled rocket engines despite the challenges presented by their use, storage and transport.  The most likely reason for this is the elimination of an ignition system given their hypergolic property-- removing one more point of failure in an extremely complex and expensive system.


Installation of the gas cylinders into the propellant terminals through the roof access

Photo courtesy of Fred Epler



One cluster at a time, each set of tanks was carefully emplaced

Photo courtesy of Fred Epler



Groups of tanks being positioned and bolted in place

Photo courtesy of Fred Epler

Cryogenic Gasses and You

Liquid oxygen and liquid nitrogen are "cryogenic gasses", which are gasses which have been chilled to the point where they change to a liquid state.  For liquid oxygen, O2 is chilled and maintained at around -170 degrees Celsius or -274 F.  It probably does not need to be said (but here I go anyway) that anything which is -100 Celsius or colder is likely to be quite dangerous.


As it was with the rest of the Titan I complex, all the piping in this area was allowed a certain degree of movement through the use of flexible connections and gimbaled joints to help prevent ruptures to the very complicated plumbing in this area.  Because LOX is a concentrated oxidizer, the piping and fittings were all stainless steel or other non-reactive metals and were cleaned to stringent standards.  Any particulate, especially oil or grease in a LOX line can produce an explosion.


A makeshift clean room at the nearby Buckley Air National Guard base for cleaning and drying components of the Propellant Loading System.  All conduit, valves and connectors had to be meticulously cleaned and dried using nitrogen gas and then wrapped to keep out contaminants prior to shipment and installation on site.

Photo courtesy of Fred Epler



Drying room with twin-column dryer at right rear.  I regret I do not know the names of the men in these pictures (and many others throughout this website) so I cannot credit them for their contribution to these early days of US missile defense.  If anyone knows who they are, please contact me.

Photo courtesy of Fred Epler


Smoking was an obvious no-no in the propellant terminal, but the liquid oxygen presented other hazards beyond violent oxidation, presenting a veritable cornucopia of potential dangers.  Chief among these dangers is the presence of oil or grease-- or any hydrocarbon that could spontaneously create a fire or explosion.  Hands, clothing, tools and anything else entering the propellant terminal had to be clean, static resistant and not emit any possible sources of ignition.


Sparks and open flame are of course not safe near LOX and dropping tools is also discouraged as it may produce a spark or if dropped on spilled LOX could also result in an explosion.  Special bronze tools are commonly employed in such environments for the simple reason that they will not produce a spark when dropped or striking another surface.


Appropriate gloves, boots and aprons (to protect against spillage) were part of the necessary gear for handling LOX.  Aprons were mostly for fill and drain operations, but leaks were always a concern.  Because of the enormous difference in temperature of piping and connectors and the ambient temperatures when cryogenic liquids are channeled through them, seals, bolts and connections expand or contract unevenly, pretty much guaranteeing leaks during a transfer.  For this very reason, a catch basin was located below the steel floor grating to collect spillage.  An emergency eyewash station and shower was provided on both levels of the propellant terminals in case of accidental contact.


Operational photo of the entrance to one of the three propellant terminals


Entrance to Propellant Terminal #1 - Present condition

Today you'll find the tunnels to the propellant terminals are in varying states of decay with #1 (pictured) displaying crusty, peeling lead-based paint and copious rust along with the standard removal of the most accessible steel, copper wiring and other salvage-worthy materials.  This is pretty standard but things get considerably more damp and in increasing severity, when you venture to launchers #2 and #3.  All the propellant terminals are flooded to some degree and are stripped in a similar fashion-- that is, very little is left.

Door to Propellant Terminal #1.  As the door attests, this was a "No Lone Zone" and you were required to have at least one other person present at all times while in this area.  This was for security as well as safety.

During operation, the propellant terminals were literally jammed with hardware.  A large amount of stainless steel and bronze, copper and other expensive materials filled almost all the usable space.  Today, as you'll see below, things are quite different.


Operational photos of the propellant terminal are hard to come by.  I've included the best of what I have, but there just isn't much.  I also don't have many photos of the terminals from my visits as they were difficult to photograph without a large flash.


Operational photo of one of the three propellant terminals.  One of the best operational photos of the propellant terminals I have seen, this shows the upper level during maintenance procedures.



A1C Brannon running down a maintenance checklist in the propellant terminal.  The checklists were in plastic sleeves so that they could be completed with a grease pencil and re-used after being wiped clean.

Photo courtesy of Fred Epler


Looking into the prop. terminal from the personnel tunnel you see remains of the almost completely scrapped Propellant Terminal #1 (Terminals 2 and 3 are no better) .  The doorway to the LOX Bay is located directly across the terminal in this photo and has been sealed with plate steel and reinforcing bars.





Very little remains aside from bare walls in most areas of the propellant terminals.  You can see the shock-mounted light fixtures on the ceiling.



The moisture here condenses on the walls and ceilings as it does in other flooded areas



Some of the upper level structure and the entrance to the LOX tunnel



These photos are taken from the personnel tunnel which is no longer connected to the upper level structure.  The water is about 8 feet below in this photo.

I wish I had gotten more photos of this area, and even more so I wish I had climbed up the remaining structure for some better shots.  The water you see here is over 2 feet deep and I guess I didn't feel like dropping my camera in it when I passed through here.  

The entrance to the LOX tunnel is at the upper right in the above photo.  I did finally venture there to get some pictures which you can see in the LOX tunnel section of the site (once it is complete, sorry it is not up yet).


A1C Brannon continuing his maintenance checklist on the lower level.  This is the LOX sub-cooler he's standing near-- it helped maintain the -274F temperature needed to keep the liquid oxygen from becoming gaseous again.


Note the accumulated frost from the piping to the tank.  You just know some airmen were throwing snowballs around these sites!

Photo courtesy of Fred Epler



Another shot of the LOX sub-cooler and A1C Brannon

Photo courtesy of Fred Epler



This is how the lower level of P.T.#1 at 724C looks today-- rusty water and steel scrap


Entrance to the LOX tunnel during operation


The entrance to the LOX tunnel today.  The wall has been removed along with the door.  You can see a small ventilation blower half-submerged at center.  Ventilation was very important to keep gasses from accumulating to the point where they could become an explosion hazard or to the degree that they would displace breathable air in the terminal.  This area maintained a positive pressure to force air to the surface via the LOX loading and vent shaft that branched off of the LOX tunnel.

From here you can move on to the LOX Tunnel, go to the Main Map, or select a destination below:


Current Location: Propellant Terminals

Main Map Propellant Terminals Missile Silos Equipment Terminals LOX Bays LOX Tunnels Utilities Tunnels

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