Cheyenne Mountain is the home of the United States' most famous early-warning sites. It houses
SPADOC and
NORAD. Iconified from the moment of its
inception in 1961 by Hollywood and television, it remains in service today, albeit not quite as it used to.
If, like me, you are in your thirties, your most vivid images of Cheyenne Mountain (unless you have actually been there) most likely come from the movie WarGames. Some of that is true, although not much. Cheyenne Mountain is, in fact, underground beneath a mountain near Colorado Springs. It does in fact house the central node of the NORAD tracking systems. Inside, however, it looks nothing like the films.
It is, essentially, a series of tunnels, some of which have long, low buildings built into them. These buildings rest on enormous (4 ft long, 1000 lb) steel springs designed to (according to the witty and wonderful Air Force) "mitigate the ground shock associated with an atomic blast."
The mountain has spent much of its life undergoing computer and facility upgrades. Beginning with SAGE, one of the first large-scale computing systems, it progressed through DEC VAXen, HP machines, magtape and punchcard readers, Novatel muxes, and more. Although the most recent series of upgrades (codenamed Granite Sentry) has been completed by Martin Marietta (now Lockheed Martin Marietta), the mountain still contains more than twenty disparate systems. Some are old enough to rely entirely on magtapes.
Now, the majority of the functions run on Sun Solaris on SPARC-based machines, using COTS software such as Sybase. As we all know, that other OS contains all sorts of fine print about not using it to control nuclear facilities, hospital gear, and other 'life-critical' equipment.
Some other not-so-dry facts. The mountain holds 4.5 million gallons of stored fresh water; it has 2.8 miles of tunnels containing roughly 7 million cubic feet of cleared space. More than 115,000 rock bolts (two-foot-plus long steel bolts to secure and strengthen rockfaces) keep it from falling in on itself. There are two full-time folk whose job is simply to tighten bolts.
Apparently, in the DEC VAX era (WarGames timeframe), the computing power of the mountain couldn't match anything like the WOPR. The tracking systems could be overwhelmed by 50 or so or more targets moving between updates, which weren't that fast - several seconds apart. The commanding officer of SAC - now USSTRATCOM - sits within Cheyenne Mountain. His or her backup is the now-grounded aircraft SAC and STRATCOM codenamed Looking Glass. There are communications links of all types into the mountain, designed to offer the best chances of maintaining contact with the U.S.'s nuclear forces and the NCA during a nuclear exchange. Telephone, telex, internet, satellite, groundwave radio, VHF, UHF, ELF, and more alphabet soup.
They do, in fact, offer tours - one bit of War Games come true. I intend to have one one day.
Facts for this w/u were taken from a variety of sources, including an article in Wired entitled Going Ballistic!, a Discovery Channel special on the mountain, and USSTRATCOM web sites.