Nuclear-powered airships seemed like a good idea during the Cold War, but for a variety of reasons—some self-evident—they never got off the ground.
For the first half of the 20th century, atomic-powered airships were the stuff of science fiction, floating across the pages of pulp magazines that envisioned a future when nuclear energy would be harnessed for the good of all mankind. It wasn’t until President Dwight D. Eisenhower’s 1953 “Atoms for Peace” address at the United Nations, however, that the idea received serious attention. Ike’s UN speech was meant to promote peaceful uses of atomic energy for agriculture, medicine and electricity generation, but the U.S. Navy’s Bureau of Naval Weapons also took note. The result would be the first military study for an atomic-powered airship.
Written in 1954 by F.W. Locke Jr., that study investigated the feasibility of using nuclear power in an airborne early-warning (AEW) airship to guard against a Soviet first strike. Locke foresaw a rigid airship powered by twin T56 gas turbine engines specially modified for nuclear propulsion. Capable of 115 mph, the airship would be approximately 25 percent faster than previous dirigibles, enabling it to remain on station even in bad weather. Locke proposed a 2-millioncubic-foot helium capacity for his airship, with a large outer envelope containing a long-range, high-resolution radar array.
Unlike airships, which use helium or hydrogen for lift, airplanes require far more power during takeoff than they do for cruising at altitude. One reason why Locke even considered building an airship is that it’s a more viable platform for nuclear propulsion than an airplane, given its low power requirement. Locke proposed a nuclear power plant that weighed only 40,000 pounds, well within an airship’s lift capacity.
As Locke saw it, the crews of nuclear-powered airships would be much less prone to fatigue because “noise and vibration should be almost entirely absent.” He also postulated that crewmen would have “the entire area forward of the cabin…for exercise.”
Given an atomic airship’s superior comfort and endurance, Locke believed it could easily patrol for 100 hours. While he admitted that airships were at a defensive disadvantage due to their high visibility and slow maneuvering, he stressed that this is less of a problem than it might seem. Fast-moving fighters can be called upon to defend airships, just as they are assigned to protect bombers. And by the 1950s there had already been proposals for airships that could carry fighter aircraft aloft. In fact, two “flying aircraft carriers,” the airships Akron and Macon, had been built in the early 1930s, though both came to grief in bad weather.
Locke’s report, the first serious examination of an atomic-powered airship, recommended further study. But its author suggested that many of the problems associated with such designs were solvable— and he wasn’t alone in that belief.
Aerospace illustrator and author Frank Tinsley had envisioned airships carrying nuclear missiles as early as 1948. In March 1956, he wrote and illustrated an article for Mechanix Illustrated recommending that the U.S. government build an atomic-powered dirigible to serve as Ike’s atoms-for-peace demonstrator.
Just over 1,000 feet long, with a helium capacity of 10 to 12 million cubic feet, Tinsley’s design was almost twice as big as Hindenburg, previously the world’s largest airship. Tinsley envisioned an atomic power plant with twin turbines, driving a huge four-bladed propeller in the stern. To assist with takeoffs and landings, ducted fans mounted on gimbals would move the airship up, down or sidewise. Tinsley also imagined a gallery encircling the engine room, where visitors could safely observe the atomic plant in use.
Rubber pontoons inflated with water could be deployed whenever the airship landed on a smooth lake surface. A helicopter landing pad built on an elevator would lift the chopper clear of the hull for takeoff, or lower it into an internal hangar where passengers could disembark. Tinsley even included an exhibition hall that could be detached and lowered to the ground, leaving the airship free to fly around, advertising the exhibit.
Tinsley’s airship was a fantasy, of course, but its inventor believed it could serve as the perfect ambassador for the peaceful use of atomic energy. “No man-made vehicle has ever presented [as] awe-inspiring a spectacle,” he wrote. Karl Arnstein, the Goodyear engineer who had designed the Navy’s Akron and Macon, called Tinsley’s airship proposal “an intriguing new approach.”
But the Eisenhower administration didn’t go for Tinsley’s idea, opting instead to build the first fission-powered merchant ship. NS Savannah was launched on July 21, 1959, at a cost of $46.9 million, more than half of which was spent on its reactor. High operating costs would eventually spell the ship’s doom, leading to its decommissioning in 1971.
In 1957 Edwin J. Kirschner published his book The Zeppelin in the Atomic Age, which promoted the use of atomic airships as aerial reconnaissance platforms for Eisenhower’s“Open Skies”disarmament proposal. Kirschner also proposed a fleet of nuclear-powered “minute men” airships that would not only identify a Soviet attack, but launch an immediate counteroffensive. Although he claimed Eisenhower’s staff was studying his proposals, nothing came of either idea.
In May 1959 Goodyear, the airship experts, finally stepped up to the plate. Assembling a group of aviation writers for a Washington, D.C., breakfast, Goodyear announced it had the ability to build a nonrigid, nuclear-powered airship by 1963. The company envisioned a 540- foot-long blimp that would hold 4.5 million cubic feet of gas and be capable of 90 mph. It was designed to carry a crew of 24 and operate at 10,000 feet, and its nuclear-powered turboprop engines were supposed to give it “unlimited range.”
The project was seen as feasible in part because of a new rubberized fabric that Goodyear had developed, capable of with standing radiation exposures of up to 100 million roentgens (an exposure of 500 roentgens in five hours is usually lethal to humans). Goodyear had built more than 260 airships, the majority of them nonrigid, and it was already producing the conventionally powered, 1.5-million-cubic-foot ZPG-3W blimp for the Navy’s AEW program. The company even had a nuclear power subsidiary with experience operating an atomic reactor.
Goodyear’s press release noted that given such ships’ inherent buoyancy, “a nuclear-powered airship could be fitted with a reactor with one-twentieth the power needed to sustain a nuclear-powered heavier than-air craft.” But the release also noted that the blimp’s “nuclear reactor would be shut down during takeoff and landing,” a nod to safety concerns.
Goodyear proposed building two types of nuclear-powered airships: one for cargo and one as an early-warning sentinel. Though the proposals were almost certainly fishing expeditions, both designs should be taken seriously. Goodyear had the experience to take on such a project, and the Navy had the money. They could easily have built either blimp.
In 1962 America’s most famous proponent for lighter-than-air (LTA) aviation, Vice Adm. Charles E. Rosendahl, was invited to testify at a House subcommittee hearing on Department of Defense appropriations. Though Rosendahl was actually there to lobby against the Navy’s elimination of his beloved LTA program, he managed to slip an endorsement for nuclear-powered airships into the Congressional Record. Rosendahl cited the former chairman of the Atomic Energy Commission, Gordon Dean, saying, “One place where the atomic engine can come into its own is the…dirigible.” He also quoted a nuclear technologist at Northrop Aircraft, Jack E. Van Orden, who said nuclear-powered airships were“practical with today’s technology.” Not only did Rosendahl fail to generate funding for nuclear-powered airships, he also lost the battle to save his LTA program after nearly 50 years in operation. The Navy shut down the program in 1962.
Perhaps the most-publicized proposal for a nuclear-powered airship came from Francis Morse, a former Goodyear engineer who was an assistant professor of aeronautics at the University of Boston. His proposal would dominate the discussion for most of the 1960s, inspiring write-ups in New Scientist, Aviation Week & Space Technology and Time magazine. Morse sought funds to build an atomic airship to promote the 1964 World’s Fair in New York City. To that end, he and four undergraduates at BU’s College of Industrial Engineering unveiled a 10-foot scale model of their nuclear-powered dirigible.
According to Morse’s calculations, an airship 980 feet long, 176 feet in diameter and with a gross lift of 760,000 pounds needed a power plant generating only 6,000 hp for propulsion. Such a small power requirement meant the total weight of nuclear reactor, turbines and shielding would amount to no more than 120,000 pounds, a fraction of the airship’s gross lift. That meant Morse’s airship could carry a significantly larger payload than conventionally powered dirigibles, making it economically attractive.
Morse envisioned an airship frame made of high-strength, corrosion-resistant alloys such as titanium and aluminum; an outer cover made from durable nylon; and gas cells filled with helium. His design called for placing the bridge inside the hull, a first for an airship. An axial corridor connected the bridge in the nose to nuclear-powered engines near the stern.
Morse preferred using a scaled-down version of a Pratt & Whitney 200-megawatt (thermal) cycle nuclear reactor. A pressurized steel sphere 12 feet in diameter would encase the reactor, and protective shielding made from lead and a lightweight laminate would sufficiently reduce radiation levels so that the crew could work safely.
Morse admitted that radiation hazards presented a serious obstacle for the design of any atomic-powered aircraft, especially since a crash could“spread fissionable material with lamentable consequences.” But he believed that crashes were much less of a problem for lighter-than-air craft because an airship’s “intrinsic buoyancy reduced the inertial forces from an impact to a manageable level.”In other words, anything containing 17 helium gas cells was bound to crash softly.
That may seem like thin gruel for those on the ground—not to mention aircrews. But despite perceptions to the contrary, conventionally powered airships had far safer operating records than airplanes. Before the Hindenburg crash, for example, commercial airships carried more than 354,000 passengers on 114,700 flights over 4.4 million miles without a single fatality. Though Hindenburg’s last flight is remembered as the infamous exception, only 35 of the airship’s 97 passengers and crew died in that disaster, far fewer than many people believe. During that same era airplanes were death traps by comparison.
Morse proposed a cargo carrier and also a 400-passenger “flying hotel.” As he described it, “The transoceanic traveler…is confronted today with two choices. Either he must buckle himself [in]to an airline seat…resigned to seven hours of inactivity; or he may avail himself of more spacious amenities aboard an ocean liner—and spend…a week at sea.” His third alternative, a nuclear-powered airship, would cut transatlantic travel to 40 hours and provide “luxury on par with the surface liner…all at the cost of a first class steamship ticket.” Of course, transatlantic ship travel was actually in the process of taking a nose dive at the time, though Morse didn’t know it.
The lowermost deck of Morse’s flying hotel contained staterooms, many with private baths. There was also a cocktail lounge, a 200-seat dining saloon, a cinema and a promenade deck “broader than on the Queen Elizabeth.” On the upper deck Morse’s airship boasted a “ballroom beneath the stars” with a transparent ceiling arching over a dance floor. Another interesting feature was an 18-seat shuttle plane, used to ferry passengers to and from the airship while it was en route. When not in use, the shuttle would be stowed in a hangar amidships.
Morse clearly had a flair for promotion. A photo taken sometime before the 1964 World’s Fair shows him standing next to a model of his airship, arms outstretched to indicate its size. Wearing eyeglasses that only an aerospace engineer could love and a suit right out of Mad Men, he looks like he’s stepped out of a Cold War filmstrip promoting “Future World.”
Morse’s atomic-powered airship design is still remembered today as something of an industry baseline. Though he considered his design technically feasible, he admitted, “The greatest problems…are not engineering or economic [but] questions of prejudice and persuasion.” What he was referring to, of course, were the Hindenburg, Macon, Akron and other airship disasters, which still haunted the public 30 years later. As a result, Morse’s proposal never got past the discussion stage despite the considerable media attention it received.
The BU professor was not alone in trying to sell the world on a nuclear airship during the Cold War years. In 1969 a proposal by Erich von Veress, a 69-year-old Austrian engineer, generated international attention. Veress called his airship the ALV-1, for Atom Luftschiff Veress, and it was even bigger than Morse’s and Tinsley’s behemoths—1,062 feet long with a helium gas volume of 14.4 million cubic feet. It had a projected gross lift of 1 million pounds, enabling it to carry 500 passengers, a crew of 100 and 100 tons of freight at speeds over 200 mph.
Veress tried to persuade several West German industrialists, research foundations and even the Bonn government to fund his atomic-powered airship. At one point, the Schlichting Shipyard in Lubeck, West Germany, went so far as to announce tentative plans to construct the $38 million dirigible. Veress even entered into preliminary discussions with General Electric to provide the reactor. But critics claimed Veress’ airship concentrated too much weight in its bow and tail (a problem with Morse’s design as well). Though this shouldn’t have been a show-stopper, the Austrian designer was unable to convince his detractors otherwise. He never ceased working on his airship design, even producing a series of beautifully drafted diagrams, but his dream never saw fruition.
Cold War rivalry drove much of the interest in nuclear-powered flight, especially during the late 1950s and early ’60s. An experimental American airplane, the Convair NB-36H, carried a nuclear reactor that operated in flight, though it did not propel the aircraft, and Russia’s Tupolev Tu-119 operated in similar fashion. Neither of those experiments resulted in a nuclear-powered airplane, but the concept of an atomic airship refused to die. Sometime in the late 1960s, the Russians also bellied up to the bar.
In 1973 the Bulgarian newspaper Trud reported that the Soviet Union had plans for a 943-foot-long nuclear-powered airship capable of carrying 1,800 passengers or 180 tons of freight at a cruising speed of 190 mph. The following year, the Associated Press published a photo showing an illustration of the Soviet dirigible.
When Jane’s Pocket Book 7 of Airship Development came out two years later, it identified the Soviet airship as the D-1, a scaled-down prototype of a larger ship, the D-4. Jane’s cited Soviet press reports stating that “test flights were…so successful that work has begun on a larger version of the craft.”No mention was made of the D series being nuclear powered, however, and Soviet press reports were famous for their exaggeration. An earlier report in Jane’s Freight Containers had suggested the D-1 was nuclear powered, but there are no indications the design ever made it off the drawing board.
The 1973 oil crisis may have lent further support to the design of nuclear-powered airships, but it wasn’t until 1983 that a seminal academic paper appeared on the subject, The Preliminary Design of a Very Large Pressure Airship for Civilian and Military Applications, by T.A. Bockrath, a Ph.D. student at the University of California, Los Angeles. With a helium gas volume of 250 million cubic feet and a gross lift of 15.4 million pounds, Bockrath’s design was theoretically capable of carrying a 5-million-pound payload at a cruising speed of 200 mph. His semirigid airship was by far the largest yet conceived. To support his mammoth ship, Bockrath proposed a central tube like a backbone running from nose to tail. His design foresaw a hull made from Kevlar 29, a strong but lightweight fabric commonly found in today’s bulletproof vests. Crew and cargo would travel in pressurized compartments hanging from the central tube, while compartments on the bottom hull would have an airlock for loading and unloading.
Bockrath imagined several uses for his ship, including as an intercontinental ballistic missile launch platform, a transport for intermodal containers, a troop and tank transporter, and a flying aircraft carrier. Based on Morse’s assumptions, Bockrath estimated his airship’s nuclear propulsion system would weigh in at 5 million pounds, or just 26 percent of its total weight of 19 million pounds.
Bockrath’s and Morse’s designs come up today whenever nuclear-powered airships are discussed. For example, a 1988 NASA paper that explored the use of a nuclear-powered airship/helicopter hybrid as a potential platform for stopping ozone depletion over Antarctica cites both works. But the last time anyone seriously looked at an atomic airship was 1999, when Aerostation, the journal of the Association of Balloon and Airship Constructors, devoted an entire issue to the subject. The editor claimed the attractions of atomic power are obvious, including: “immense endurance and range, fixed weight of power plant and fuel…[and] the prospect of operating extended periods without refueling.”
Though the past decade has seen a rebirth, if not exactly a resurgence, in dirigibles (Germany’s Zeppelin NT being one recent example), the nuclear-powered airship has failed to take shape as a viable alternative to conventionally powered LTAs. Despite the proposals put forth in the United States, Russia and Germany, none of the atomic airship designs ever got beyond the drawing board. But the fact that such plans were being seriously discussed at a time when atomic energy seemed a viable solution to many of the world’s problems shows that nuclear-powered airships came a lot closer to realization than many people realize.
Given today’s emphasis on green technology, the future may belong to another form of energy: solar power. Helios Airships, Solar Ship, Hybrid Air Vehicles and other companies have already developed designs for solar-powered and hybrid airships for military and civilian use—some of which have already flown. Perhaps this is how “atomic airships” will finally become a reality: by harnessing the limitless power of the sun’s nuclear fusion.
John J. Geoghegan writes frequently about unusual aviation and science topics. His forthcoming book Operation Storm, due from Crown in May 2013, is based on his article about Japan’s I-400 subs and their Seiran aircraft for the May 2008 issue of Aviation History. Further reading: The Zeppelin in the Atomic Age, by Edwin J. Kirschner.
Originally published in the January 2013 issue of Aviation History. To subscribe, click here.