Hardtack Teak

HARDTACK-Teak was an nuclear test performed during Operation Hardtack I. On 1 August, 1958, the shot reached an altitude of 78 km. "Teak" caused communications impairment over a widespread area in the Pacific basin. This was due to the injection of a large quantity of fission debris into the ionosphere. The debris prevented normal ionospheric reflection of high-frequency (HF) radio waves back towards Earth, which disrupted most long-distance HF radio communications.

The 3.8 megaton detonation was planned to occur at an altitude of 250,000 feet approximately six miles south of Johnston Island. However, due to a programming failure it burst directly over the island at the desired elevation making the island the effective ground-zero. This brought the explosion 2000 feet (approximately 2/5ths of a mile) nearer than intended to the launch site control and analysis crews.

Personal Account

quote|I started working for "ABMA" (remember that acronym?) in early September, 1958. Explorer 1 already had been launched and most of the people I would eventually work with were gone. Byrne, George Matthews, Ted Hershey, and others. They were on a very small island called Johnston Island about seven hundred miles approximately west of Hawaii. The project was classified at the time, nobody was talking, so I had no idea where every one was.

They 'night launched' a Redstone from there with a thermonuclear warhead, four Megatons yield I believe, to detonate 50 miles up. The blast was seen in Hawaii and was bright enough to read a newspaper by. The purpose was to study the signal (there was only one, 108 MHz (MC then)) from the Explorer 1 after transmission through the ion cloud generated by the blast. This was called Operation Hardtack and there were two Redstone launches and several other A-bombs detonated as part of that program.(*)

Byrne had a couple of interesting stories to tell about that operation, one I've used many times over the year to illuminate some fallacies of statistics and forecasting. Everybody on the island was concerned, of course, about what would happen if something failed. The Atomic Energy Commission had done risk projections and presented the following statistics (approximate order of magnitude - don't remember exactly). If the missile fails to follow its programmed trajectory the odds that the bomb will detonate is only once in 10e7 (ten million) times. If then the missile falls back onto the island the odds that the bomb will go off on impact (thus removing Johnston island from world geography) is only once in a million times (ten times more likely, but still very unlikely).

There was an Air Force range safety officer, just like at the Cape (Kennedy Space Center), and our guys were running a Beat-Beat interferometer Range Safety tracking system, again just like at the Cape (at that time - one of the first projects I worked on with Frank was the Beat-Beat Mk2 that was a significant upgrade and simplification). The launch trajectory was up 50 miles and over 50 miles - the over part we called the "program maneuver". And guess what - the missile did NOT program over and so went straight up over Johnston Island. Frank said the Range Safety Officer went into indecision grid lock and just got up and walked away from his console rather than destroy the overhead missile.

While every one was wondering if their block house could withstand the missile crashing on it from 50 miles up (an impact detonation would leave the blockhouse as a dust cloud floating in mid air over a 400 ft deep crater) - THE BOMB WENT OFF. So much for one in ten million. It turns out, the bomb triggering device counted the pulses coming out of a guidance module called the program device. The Redstone vectored its thrust using four carbon veins/paddles that deflected the rocket exhaust. The Redstone engine was not gimbaled like later boosters. So each pulse would 'bump' the missile flight direction causing it to slowly pitch over as planned. The pulses came out so the bomb fusing put a check mark next to the 'Program' item, but the missile didn't 'bump'. The carbon veins were driven by a gearbox. They later determined that when the gearboxes were made a cleaning process was accidentally skipped leaving metal chips that jammed the gearing.

The operation there had a concrete blockhouse and several instrumentation vans that were built up and shipped to Johnston Island. The blockhouse had some very small windows with very thick glass (maybe 6-in thick), but the Atomic Energy Commission told the launch crew to fit plywood coverings over the windows. Frank said that when the bomb went off the light that came through the cracks around the plywood was bright enough to hurt your eyes, and scared the hell out of everybody. despite being essentially in space the blast produced a shock wave that damaged the instrumentation vans and raised dust in the blockhouse. And this from 50 miles away, in a near vacuum.

A fascinating film called sic|"Beyond Trinity" is a documentary on all our above ground nuclear testing and was the only other place I've heard about Operation Hardtack.|Frank Byrne, a scientist present during this launch, as recounted by a co-worker, Wilfred (Bill) Wood.

See also

* High altitude nuclear explosion
* Operation Argus
* Program 437
* Starfish Prime