Nike-Hercules ready for launch.

Nike Missile Site SF-88L

Mill Valley, California

We admit -- it's an eerie thrill to watch a vintage Cold War missile rise up from its nuclear hell pit onto a picturesque California coastal hillside. America's most well-preserved defensive nuclear missile site comes unnervingly alive at Fort Barry in Golden Gate National Recreation Area, when retired missile personnel return to their posts and reveal America's mothballed military secrets.

Sentry post for Battery A.

"Something's gonna get through," one veteran missile officer assured us about theoretical enemy bombers heading our way. "That's what the Nike missile was designed to stop." America's last line of defense against nuclear vaporization of cities was the US Army's Nike program. Nightmare scenarios imagined the Soviet Union's long range bombers slipping past air defenses and targeting population centers to deliver their nuclear payloads.

The Nike was a surface-to-air missile. At its deployment peak, 300 Nike sites were arrayed across 30 states and ringed around metropolitan areas from 1954 to 1974. The installations were staffed by Army air defense units working with the Air Force, hooked into the early detection NORAD network in defense of the homeland. At any moment, Nike site status might change from sleeplessly vigilant to launch-a-go-go.

Radar and scope vans.

Most Nike sites are long gone -- plowed under for civilian parks or peacetime development. Remnants survive as fenced off structures or stripped concrete radar platforms. We've taken the tour of NJ's Sandy Hook site, also on NPS property, where there have been efforts to preserve the installation, but lacking funding to get very far. California's SF-88 Nike Missile Museum is the only fully restored site, and the best place to see Nike battery history in operation.

Cutaway of missile explosive warhead.

There were eight launch sites in the San Francisco Bay Area. Fort Barry's SF-88 had been sheltered from demolition in part due to its location on National Park Service land. There in the Headlands, other vestiges of seacoast military history have been lovingly preserved. SF-88L (L for "Launch") is staffed and maintained by enthusiastic volunteers. The facility includes SF-88A ("Administration"), not part of the tour; and SF-88C ("Control") on top of a hill 2 miles away, a strenuous hike.

The SF-88L tour starts at the sentry station next to the Battery A gate. Sites were fenced, though the locations were not secret. Part of superpower attack deterrence was to make sure the enemy knew these batteries existed. In the 1950s-60s, the Nike missile radiated a strange aesthetic beauty, admired by the Americans for its design and patriotic goal to save lives. They could be spotted in town parades, and were popular as children's plastic toy models. Public tours at launch sites were part of civilian outreach (We recall witnessing a missile raised up for our awestruck Cub Scout pack in the late 1960s, at a NJ Nike base a mile from Bell Labs, which had helped the Army develop Nike missile systems).

Stairs down to the underground missile storage.

Expert docents and rangers describe every facet of the weapons systems. The site operated around the clock shifts, with 130 soldiers on duty. The call to prepare for firing might come at any moment.

The Nike-Ajax Warhead was the first generation -- a supersonic (Mach 2.3) projectile with a 12-inch diameter carrying conventional high-explosive warheads. Its liquid propellent thrust could could carry it to a target 25-30 miles away up to an altitude of 50,000 ft. The missile warhead would fragment in the path of the bomber -- a Russian Tu-95 Bear -- perhaps close enough to destroy it. Strategic bombers were slow, and fighter jets from nearby airbases were scrambled to eyeball suspicious aircraft.

As enemy aircraft evolved, the Nike-Hercules Warhead missile system upgrade started to replace the Ajax in 1958. The Hercules could carry a small nuclear warhead, had a longer range of up to 100 miles, and could ascend to take out aircraft flying at 100,000+ ft. In tests it reached Mach 3.65, and scored hits at a closing speed of Mach 7. The SF-88L site was modified to accommodate the new missiles, which required more power and storage space underground, but no onsite fueling like its predecessor, since Hercules used solid fuel boosters.

Always remember to remove the red safety tip before launch.

To secure the now nuclear-tipped arsenal, the launch areas were no longer open to casual public tours, and dogs patrolled with armed sentries. "That guard dog was trained to kill you," said our guide, a missile crew veteran. "So don't come through that fence. If you're caught in here, you're shot, or they turn that guard dog on you. The guard dog knocks you over and tears your throat out."

In the scope van.

We admired our steely-eyed guide's policies of deterrence. There would be no bronco-buster missile selfies today.

Visitors can wander through the Generator Building, the Acid Fueling Station (which later became the "Warheading Building"), and try their hand at a launch sequence in the battery control van next to the revolving radar units.

The underground "A" section magazine invites exploration. A staircase built in 1964 (apparently a luxury back in Nike pit crew days) leads down to a concrete chamber. We're surprised to find actual Nike missiles, some up to 41-ft. long, and we count ten Nike Hercules missiles, totally defanged (but keep in mind we're not professional WMD inspectors). SF-88L preservationists didn't skimp by acquiring just one missile, or painting an interpretive mural of missiles.

Docent cap military flair.

Because the magazine is underground, it suffers from ground water problems, and required constant pumping, maintenance of electrical and hydraulics. This is a typical problem with America's deactivated bunkers and missile silos. Fortunately, SF-88L has expert help and the ability to stay pumped. And lots of plastic buckets for rainy day roof leaks.

Our guide sets a Nike Hercules deployment in motion. A klaxon alarm sounds -- to alert anyone on the surface to get off the pit doors. Then the hydraulic elevator lifts the missile to the surface. From there the missile can be raised on a launcher erector to launching position.

Launch erector raises Nike-Hercules into position.

Before a real launch, an accurate trajectory to reach the target would be determined with incoming radar data. The effortless multi-tasking and speed to calculate taken for granted today was unavailable in the analog mid-20th century. According to our guide, "The radar could only target one incoming enemy at a time."

Two "scope" crews would unlock separate safes to access missile firing authentication codes. The Nike battery would be assigned a target and would fire when commanded. Veteran crew members recount close calls during testing and suspicious aircraft alerts. They knew that San Francisco might be at stake, but it also might be a mistake, such as a misidentified commercial plane.

Once fired, a pair of tracking radars provided continuing position data on the outbound missile and the inbound target. A 100 mile flight might take 90 seconds. The computer would adjust the guided missile trajectory along the way, determine the point of "highest kill probability" near the enemy aircraft, and detonate the warheads.

Launch console status lights - from Designate to Burst.

Note: They don't actually fire a missile for tours.

In the politically turbulent 1960s, the Nike Zeus -- an even more sophisticated ABM system -- failed to find a nation comfortable with its deployment in the neighborhood. Also, strategic focus had shifted to submarine and land-based Intercontinental Ballistic Missiles. The Nike sites had a diminishing role (though it had some adoption overseas by allies). By 1974, all of the fire units in the U.S., including SF-88, ceased operations. The deactivated SF-88 site didn't leave much equipment behind, but the buildings and underground facilities with elevators and electrical systems remained intact. It was turned over to the National Park Service.

The Soviet attack never came. The colossal cost of unused defense systems such as Nike might seem like a huge waste, and there are plenty of critics who question whether there was much of a likely threat. But in the superpower chess game of Mutually Assured Destruction, a missile shield for cities was a strategic piece.

Nike veteran crew open house is the first Saturday of the month.