Sunday Ship History*: Skyhooked

Flights of bombers from the islands of Guam and Tinian under the command of General Curtis LeMay were dropping incendiary bombs on Japan. Long range B-29s of which the Japanese had no equivalent, leading them, as is often the case with those in dire need, to innovate. Their innovation for strategic bombing against the United States took the form of balloons. Big balloons, filled with hydrogen and carrying bombs across the Pacific to attempt to strike terror among the Americans, as set out here:

The concept for the IJA balloon offensive was the brainchild of the Japanese Ninth Army Technical Research Laboratory, under Major General Sueyoshi Kusaba, with work performed by Technical Major Teiji Takada and his colleagues. The balloons were intended to make use of a great strong current of winter air that Japanese unmanned balloon flights by both the IJN and the IJA had discovered flowing at high altitude and speed over their country.

The "jet stream", as it would become known, blew at altitudes above 9.15 kilometers (30,000 feet) and could carry a large balloon across the Pacific, a distance of more than 8,000 kilometers (5,000 miles), in three days. Such balloons could carry bombs to the United States and drop them there to kill people, destroy buildings, and start forest fires. The Japanese named the weapon "fusen bakudan", which literally means "balloon bombs", but which has been translated as "fire balloons". The program was formally referred to as "FU-GO" -- "fu" being a character in the Japanese phonetic alphabet, and "go" meaning "Series 2" or "Model B".(Fu-Go photo from here.)

* Building a balloon that could survive a three-day trip across the Pacific and then automatically drop its warload was technically challenging. Since a hydrogen balloon expands in the sunlight and rises, then contracts at night and falls, the Japanese engineers had to develop a battery-operated automatic control system to maintain altitude. When the balloon descended below 9 kilometers (29,500 feet), it electrically fired charges to cut loose sandbags. The sandbags were carried on a cast-aluminum four-spoked wheel, and discarded two at a time to keep the wheel balanced. Similarly, when the balloon rose above about 11.6 kilometers (38,000 feet), the altimeter activated a valve to vent hydrogen; the hydrogen was also vented if the balloon's pressure reached a critical level.

After three days, the ballast would be gone, but by that time the balloon was assumed to be over the United States. The final command of the control system fired charges to release the bombs, which were also carried on the wheel, and lit a 19.5 meter (64 foot) long fuze that hung from the balloon's equator. After 84 minutes, the fuze ignited a flash bomb that destroyed the balloon.

The balloon had to carry about 900 kilograms (1,000 pounds) of gear, which meant a hydrogen balloon with a diameter of about 10 meters (33 feet). At first, the balloons were made of conventional rubberized silk, but there was a cheaper way to make an envelope that leaked even less. An order went out for ten thousand balloons made of "washi", a paper derived from mulberry bushes that was impermeable and very tough. It was only available in squares about the size of a road map, so it was glued together in three or four laminations using paste derived from a tuber with the Japanese name of "devil's-tongue".

And thousands of balloons were dispatched:

The Japanese employed some 1,000 "Fu-Go Weapons," or balloons equipped with bombs, which they sent eastward across the Pacific. These landed in some 16 U.S. states, as well as in Alaska, Canada, and Mexico. They killed only six civilians—a mother and her five children in Lakeview, Oregon, in May 1945—and the fact that the U.S. media agreed not to report news of the bombings greatly blunted their potential psychological effect.

Eventually, someone noticed a pattern:

By early 1945, Americans were becoming aware that something strange was going on. Balloons had been sighted, explosions heard, from California to Alaska. An object that witnesses described as like a parachute descended over Thermopolis, Wyoming, followed by the explosion of a fragmentation bomb; shrapnel was found around the crater. A P-38 Lightning fighter shot a balloon down near Santa Rosa, California; another was seen over Santa Monica; and bits of washi paper were found in the streets of Los Angeles. Two paper balloons were recovered in a single day in Modoc National Forest, east of Mount Shasta. Near Medford, Oregon, a balloon bomb exploded in a blast of flame. The Navy found balloons in the ocean. Balloon envelopes and apparatus were found in Montana, Arizona, Sasketchewan, in the Northwest Territories, and in the Yukon. Eventually, an Army fighter somehow managed herd one of the balloons around in the air and force it to ground intact, where it was examined and photographed

And that captured balloon provided the Americans with an idea that came to fruition after the war. As noted in Space-Based Reconnaissance, the U.S. found itself in need of knowledge - knowledge of what was happening behind the "Iron Curtain" and in Red China:

Beginning in 1946, Army Air Forces conducted reconnaissance flights along the borders of the Soviet Union in order to determine the size, composition, and disposition of Soviet forces behind the Iron Curtain.2 The intelligence collected from these missions was limited, since the aircraft only flew on the periphery of the Soviet Union and its satellite states. Some military leaders at the time recognized that if the United States were to prevent a future surprise attack by the Soviet Union, accurate intelligence was needed before hostilities began. The U.S. leadership determined that acquiring reliable intelligence about the economic and military activities and resources of a potential foreign adversary could only be accomplished through periodic high-altitude overflights in peacetime.3

The necessity of peacetime overflights was reinforced after a series of events stunned the United States between 1947 and 1950. A Communist-controlled government assumed power in Poland in 1947. A Communist coup in Prague ended that nation’s independence in 1948, and the Soviet Union blockaded Berlin later the same year. In 1949 the Soviets surprised the United States by detonating their own nuclear device. The United States was further shocked when the Chinese Communists swept to victory in 1949 and the North Koreans launched a surprise attack on South Korea in 1950.

Now, the U.S. Navy had been working with some big balloons, doing some research into cosmic rays and other such stuff under the name "Project Skyhook":

In 1947, the U.S. Navy began Project Skyhook, which used very large unmanned plastic (polyethylene) balloons to loft research payloads of various kinds (e.g. cosmic ray research) to altitudes of up to 30 km (100000 ft). The initial prime contractor for the Navy's Skyhook balloons was the Aeronautical Division of General Mills, Inc. Skyhook eventually became a very successful program, and its balloon technology was also used by the Air Force. In fact, the name Skyhook became a synonym for large high-altitude plastic balloons, even if they were launched by other agencies under different programs.

At low level immediately after launch, the lifting gas (hydrogen or helium) in Skyhook balloons formed a small bubble at the top of the envelope, giving the whole balloon a rather "limp" look. At the lower air pressure at higher altitudes, the gas expanded and eventually filled the whole envelope, which could reach diameters of more than 30 m (100 ft) in some balloon models.

Photo caption:

In the late 1940s, Project Skyhook balloons provided a stable vehicle for long duration observations at altitudes in excess of 100,000 feet. Balloons, long used for collecting meteorological data, now offered the opportunity of collecting highly specialized information and photographs. This photograph shows Skyhook Ballon 93 leaving the deck of the USS Norton Sound AV-11 on March 31, 1949. (U.S. Navy Photo RELEASED - 11/7/2003)

But the key to these balloons was a device, based on that regulating mechanism from the Japanese fire bomb balloons that regulated their altitude, as set out here:

The unique ballast control devices on the balloons, the real breakthrough that made their trans-Pacific range possible, were studied by US balloon designers in the postwar period and helped provide the inspiration for more advanced systems that would be applied to US high-altitude "constant-level" balloon projects.

Well, one man's science project becomes another man's reconnaissance tool, and before the development of the U-2, having a balloon carrying sensors or cameras over forbidden territory to gather information seemed like a dandy idea. And so, other projects began, such as Project Mogul:

Project MOGUL was first conceived by Dr. Maurice Ewing of Columbia University, NY, and Woods Hole Oceanographic Institution, MA. Dr. Ewing had conducted considerable research for the Navy during World War II, studying, among other things, the "sound channel" in the ocean. He proved that explosions could be heard thousands of miles away with underwater microphones placed at a predetermined depth within the sound channel. He theorized that since sound waves generated by explosions could be carried by currents deep within the ocean, they might be similarly transmitted within a sound channel in the upper atmosphere. The military application of this theory was the long-range detection of sound waves generated by Soviet nuclear detonations and the acoustical signatures of ballistic missiles as they traversed the upper atmosphere.
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Project MOGUL initially focused on three areas of technology: (1) an expendable microphone, capable of detecting, at long range, low-frequency sound transmissions generated by explosions and missiles; (2) a means of telemetering these sounds to a ground or airborne receiver; and (3) a system from which to suspend the microphone and telemetering device in the upper atmosphere for an extended period of time. To meet these criteria, contracts were awarded by AMC to Columbia University (AMC contract no. W28499-ac-82) for the acoustical equipment, and to New York University (NYU) for the development of constant-level balloons (AMC contract no. W28-099-ac- 241). After the initial contracts were awarded, Project MOGUL branched out into many areas related to the geophysical properties of the upper atmosphere, including radiowave propagation, radar propagation, ionospheric physics, solar physics, terrestrial magnetism, meteorological physics, and weather forecasting.

MOGUL never really got off the ground, though there are allegations that it was a classified MOGUL balloon that sparked the famous Roswell, New Mexico report of a "flying saucer crash" -

Based on the above, it appeared likely that the debris found by the rancher and was subsequently identified as a "flying disc" by personnel from Roswell AAF was, with a great degree of certainty, MOGUL flight no. 4, launched on June 4, 1947.

This, as will be discussed later, is not the last UFO situation attributed to the various balloon projects which all got tagged as "Skyhook."

The Air Force and the Navy were out there ballooning. The Navy was launching balloons off ships including escort carriers and USS Norton Sound (AV-11).

The Air Force was launching from airfields and other locations, but essentially using Skyhook balloons under a series of different project names:

In July 1950, Charles B. Moore of General Mills had conducted four test flights of Skyhook-type balloons with a camera payload. To the U.S. Air Force he presented the concept of camera-equipped balloons, which could float across the Soviet Union using strong winds (the "jet stream") at very high altitude, above the reach of Soviet air defences. In November 1950, the USAF officially began the development of a balloon reconnaissance system under secret project MX-1594 Gopher.

Design goal for Project Gopher was a balloon, which could carry a 225 kg (500 lb) payload gondola to 21000 m (70000 ft), and remain there at constant altitude for at least 16 days. Originally it had been hoped that Gopher could conduct the first operational missions by the end of 1951, but this proved to be far too optimistic. A series of test flights in 1952 was only partially successful, mainly because of continuing problems during balloon launch and with payload reliability. Because the USAF was dissatisfied with General Mills' progress, the balloon production contract was terminated in August 1952, and further balloons were ordered from Winzen Research. Project Gopher was a top secret project, but the balloon test flights could obviously not be hidden from the public. Therefore all test flights were officially part of Project Moby Dick (MX-1498), the USAF's unclassified research balloon project. Moby Dick had been started around the same time as Gopher, and used Skyhook balloons to measure global high-altitude wind patterns. Gopher's camera gondolas, which could parachute to earth anywhere after a test flight, were accordingly labeled as Air Force property (together with a fire hazard warning to discourage potential souvenir hunters).
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n July 1953, the USAF finally decided to develop Gopher into the WS-119L operational balloon reconnaissance system, codenamed Grandson. In spring 1955, WS-119L was finally ready for operational training, and the program's code name was changed again, to Grayback. Between May and October that year, more than a hundred WS-119L balloons were launched under operation "Moby Dick Hi" (as usual, the Moby Dick name was used as cover). Although only 11 successful mid-air recoveries were made in 33 attempts, WS-119L was considered ready for use at the end of 1955. President Eisenhower gave approval to begin the overflights in January 1956, but had the flight altitude of the balloons limited to 16800 m (55000 ft). This was reportedly done, because the higher-flying Lockheed U-2 aircraft was under development at that time, and the Soviets should get no unnecessary motivation to develop new very high-altitude interceptor aircraft and missiles before the U-2 had begun its overflight program.

The USAF had set up WS-119L launch sites at five locations in Scotland, Norway, Germany (2) and Turkey. An official statement was issued, saying that scientific Moby Dick balloons would be launched on extended flights in the northern hemisphere. To support this cover story, a total of 30 research balloons were launched from January to July 1956 from Hawaii, Okinawa and Alaska under operation White Cloud. The code name for the WS-119L reconnaissance flights was Genetrix. Operational WS-119L payloads had a tracking beacon, which was activated at a preset time several days after launch. This time was calculated to occur after the balloon had exited Soviet or Chinese air space, but before it sank too low because of loss of gas and ballast depletion (the gondola was automatically cut free if the balloon descended below 30000 ft). The tracking beacons were needed by the recovery teams to locate the balloons.

Between 10 January and 6 February, a total of 448 balloons were launched, and resulted in 44 successful camera gondola recoveries. Of the about 380 balloons, which actually reached Soviet airspace, more than 300 were either shot down or came down prematurely because of malfunctions or ballast depletion. The balance of the unsuccessful balloons reached the recovery zones, but couldn't be retrieved for various reasons. The end of the Genetrix flights was caused by the relatively low rate of success as well as the increasing political problems caused by the overflights. The Soviets eventually displayed captured gondolas to the public, explaining that they contained reconnaissance cameras and no meteorological equipment.

The Genetrix photos covered only a small part (8%) of the Soviet and Chinese land mass. Because of the balloons' drift pattern, particularly interesting areas in high latitudes were not covered at all. Nevertheless, Genetrix was not considered a complete failure. The high-altitude camera system made photos of excellent quality, and the WS-119L mid-air-retrieval principle would be used several years later for the retrieval of film capsules from the United States' first photo-reconnaissance satellites.

The balloons might carry cameras such as the DMQ-1:

Gopher's AN/DMQ-1 payload consisted of a gondola with the reconnaissance camera system. The main camera had two angled lenses at the bottom of the gondola, and took pictures at fixed intervals (6.25 minutes in the 66CT, 12.5 minutes in the 128TT). A second camera took wide-angle panoramic photos to determine the general geographical location of the balloon. A small photoelectric cell at the bottom of the gondola automatically shut down the cameras when it became too dark for useful photos. To recover the gondola, it was cut loose either automatically after a predefined time, or by radio command when a suitable recovery area had been reached. The gondola package then descended under a parachute. In balloon and camera test flights, the gondola would land on the ground, but in operational reconnaissance missions, it would be caught and hauled in in mid-air by specially converted C-119F cargo aircraft. There was also an ELINT (Electronic Intelligence) payload package, designated AN/DMQ-2, but its development was not completed in time, and it would therefore never be used operationally.

Confused yet? Now, remember that many of these projects were classified. And remember that the balloons would change shape as they rose through the atmosphere (the balloon expanding as the outside air pressure dropped and, at twilight, because of their altitude, they would reflect and refract sunlight long after sunset at ground level, giving the appearance of being lit from within). There seems to be evidence that one "Skyhook" launch may have cost the life of a pilot who was chasing what was a UFO:

A classified US Air Force project was based from CCAFB (Clinton County Air Force Base), known as Operation Skyhook. Skyhook involved the launch of huge observation balloons for upper atmosphere research. In January 1948 an F-51 Mustang was dispatched from Indiana to intercept an unidentified flying object detected on radar. The UFO was in fact a USAF Skyhook balloon launched from CCAFB. The pilot died in a crash while attempting to intercept the 73 ft diameter balloon. His death instigated a furor of UFO investigations and heightened civilian interest in the UFO phenomena.

And some truly incredible science fiction movies like Earth vs. The Flying Saucers, in which the good guy scientist actually runs a project called --you got it-- Skyhook!

An alleged "insiders" history of the "classified" Skyhook programs can be found here, asserting that the UFO "cover story" was suggested by the CIA to help conceal the real mission of some of the flights:

All this intrigue came to a head when the CIA suddenly showed up at our office and at launches. UFO reports peaked in 1952, as our local Skyhook activity increased from ninety-two hours the previous year to 694 hours aloft. Moreover, launches from the Moby Dick West Coast sites were commencing. Eventually they, along with additional sites in Missouri and Georgia, contributed 640 flights.

The CIA requested that we not identify most of those sharply increasing Skyhook reports. The strategy was to generate a UFO outbreak over the USA extending to the USSR when our WS-119L Skyhooks arrived there. Ironically, the ploy initially worked, since the Soviet Air Force could not intercept the first wave. They allowed their public to play our UFO game. The strategy ended after a few leaking Skyhooks were shot down and the payloads were exhibited, along with protests, to President Eisenhower.

Thus, complex interplay of Moby Dick, WS-119L, and UFO reports defined the unique role of our Blue Book office in that era. Since top-secret WS-119L was not declassified until more than thirty years later, that intrigue can only now be addressed.

Although initial phases of WS-119L were launched from Europe and Turkey, a final phase, WS-461L, was launched from the Pacific. There was a direct parallel to Moby Dick, where unclassified Project White Cloud launched Pacific flights to obtain trajectory data for WS-461L. In the April 1994 issue of Omni magazine, a retired airman proclaimed solid proof of UFO activity. He had glimpsed logs from the European NATO Command Center for 1958. They reported UFOs coming out of the USSR at 100,000 foot altitudes. That nicely described WS-461L flights cruising in from the Pacific Ocean launches.

Skyhook derivations continued into Project GENETRIX:

By far, the most significant use of balloon reconnaissance during the Cold War was Project GENETRIX. The program had its origins in a 1951 study by the RAND corporation, and in December 1955, President Dwight D. Eisenhower gave approval for the U.S. Air Force to launch 516 camera-carrying balloons over Eastern Europe, the Soviet Union, and the People's Republic of China.

GENETRIX proved a disaster in several regards. Only 34 balloons—about 7% of the total—survived and produced usable, useful images. Worse than the poor return ratio was the public-relations opportunity that the project provided to the communist bloc, which protested U.S. spying and used information on GENETRIX for propaganda purposes.

Central Intelligence Agency (CIA) officials called on the air force to halt GENETRIX, which it did in February 1956. At the time, the CIA was planning the launch of U-2 overflights, and they feared that GENETRIX would turn Eisenhower against the concept of overflights. Additionally, they were concerned that the program might negatively affect an effort by the Free Europe Committee, a CIA front based in West Germany, to drop propaganda leaflets over Eastern Europe.

The failure of GENETRIX concealed several successes. The images of the Soviet Union it did produce provided the best available record between World War II and the advent of the U-2 reconnaissance plane and later satellites. Additionally, the high-flying balloons, which averaged an altitude of 45,800 feet (13,960 m), provided data on wind currents that helped scientists determine the best flight paths for the U-2.

Finally, the most curious benefit of GENETRIX was the fact that a steel bar that secured the envelope, cameras, and ballasting equipment happened to measure 2.99 feet (91 cm)—exactly the same size as the wavelength of Soviet radar known as TOKEN to NATO (North Atlantic Treaty Organization) forces. Because it resonated when TOKEN pulses hit it, the bar helped NATO radar operators locate previously unknown radar installations. This, too, aided the U-2 project.

The Navy continued to launch experimental balloons:

Ten-million cubic foot "Winzen" research balloon on the carrier's flight deck just prior to launching, during Operation "Skyhook", Refly "B", 30 January 1960.
The balloon carried scientific devices to measure and record primary cosmic rays at 18-to-22 miles altitude. (Caption to the topmost photo of the carrier Valley Forge)

Several images of such launches are available at the ONR website here.

Project Churchy, a 1953 program funded by ONR, included the launch of 13 Skyhook balloons from the flight deck of the Navy´s seaplane tender, USS Currituck AV 7 near the Galapogos Islands. The balloons collected valuable cosmic ray and meteorological data. (U.S. Navy - 11/7/2003)

With the possible exception of that unlucky F-51 pilot, these Skyhook balloon flights didn't result in any deaths and may have saved the lives of some of the follow-on U-2 pilots.

So offer up a salute to the Skyhookers!

I should note that balloon borne research continues, as set out here:

A new NASA project will use more than 40 high altitude balloons to return new scientific insights about Earth's Van Allen Belts. The type of radiation in the belts can be hazardous to astronauts, orbiting satellites and aircraft flying in high altitude polar routes.

The new mission is called the Balloon Array for Radiation-belt Relativistic Electron Losses, or BARREL, and its principal investigator is Robyn Millan of Dartmouth. BARREL will fly in 2013 and 2014, and will provide answers to how and where the Van Allen Belts periodically drain into Earth's upper atmosphere. BARREL will fly in conjunction with NASA's Radiation Belt Storm Probes satellites, due to launch in 2011.

*Monday edition