Some of the most recognizable and iconic conceptual spacecraft designs ever proposed are those of Wernher von Braun's space popularization campaign of the 1950s. This post will look at just one of them in detail: the three-stage ferry rocket for launching crews and cargoes into Earth orbit that appeared in the pages of Collier's, a popular American weekly magazine, and the book Across the Space Frontier.

The ferry rocket took three main forms. The first, which von Braun designed in 1948 while interned by the U.S. Army with other Operation: Paperclip Germans in the New Mexico desert, was relatively stubby. It is not pictured here. As described in Von Braun's The Mars Project, published first in 1952 in a German spaceflight journal and in the U.S. the following year as a slim book, the ferry rocket's first stage, with broad stabilizing fins, would have taken the form of a drum 20 meters in diameter and 29 meters tall with a dry weight of 700 metric tons and a propellant load of 4800 metric tons.

The first stage alone would thus have weighed almost twice as much as the three-stage Saturn V rocket configured for Apollo lunar missions, which at about 3000 metric tons remains the largest, heaviest rocket ever built. The second and third stages would have brought the ferry rocket's total weight at liftoff to a whopping 6400 metric tons, of which propellants would have accounted for 5583 metric tons.

Von Braun's conservative choice of hydrazine fuel and nitric acid oxidizer was the chief reason that his Earth-to-orbit ferry rocket weighed so much. He chose them over more energetic, more efficient cryogenic propellants, such as liquid hydrogen and liquid oxygen, because they were well understood and relatively easily handled. They could, for example, be stored at room temperature without boiling and escaping. The Saturn V, first flown in 1967, relied on liquid oxygen in all three of its stages and liquid hydrogen in its second and third stages.

The second stage would have measured just 14 meters tall from its base, where it joined the top of the first stage, to its top, where it joined the 9.8-meter-diameter base of the third stage. It would thus have tapered sharply, accentuating the 1948 ferry rocket's squat appearance. The second stage would have had a dry weight of only 70 metric tons and a propellant load of 700 metric tons. It would have been the only stage that lacked large fins or wings.

The winged, piloted third stage, designed to reach and return from Earth orbit, would have measured 15 meters from nose to tail and 52 meters across its wings. Von Braun compared its fuselage to a "stubby artillery shell." He divided its interior volume into two main spaces: a 6.5-meter-long aft compartment for propellants, rocket motors, and valves and pumps; and an 8.5-meter-long, 7.5-meter-wide forward compartment for crew and cargo.

Upon separation from the spent second stage at an altitude of 64 kilometers, the third stage would have weighed 78.5 metric tons. When it reached apogee, the highest point in its elliptical initial orbit, it would have fired its rocket motors to perform a 17-second "Maneuver of Adaptation" to lift its perigee, or orbital low-point, above Earth's atmosphere. The Adaptation maneuver would have trimmed its weight to 66.6 metric tons. In its nearly circular orbit 1730 kilometers high, the third stage would have completed one circuit of the Earth every two hours.

After dropping off 25 metric tons of cargo, the third stage would have been turned so that its motors faced in its direction of motion. Once positioned, it would have burned 5.2 metric tons of propellants to perform a 14.8-second "Return Maneuver in Orbit," trimming its weight to just 27 metric tons. Of this, five metric tons would have comprised unspecified cargo for return to Earth. After Earth-atmosphere reentry, the gliding third stage would have touched down on wheeled "tricycle" landing gear at a speed of only 105 kilometers per hour on a concrete runway near its launch site.

The October 1951 Symposium on Space Travel, held at the Hayden Planetarium in New York City, brought von Braun's ferry rocket to the attention of Collier's editors. In their 22 March 1952 issue, they published "Man Will Conquer Space Soon," a colorful 28-page overview of the Hayden symposium. A description of Von Braun's ferry rocket, tailored to educate and excite the man in the street, filled nine of those pages; articles on von Braun's proposed wheel-shaped space station and problems of space medicine and space law rounded out the special section.

"Man Will Conquer Space Soon" was popular enough that it was expanded to 147 pages and published late in 1952 as a book called Across the Space Frontier. A detailed account of Von Braun's ferry rocket took up more than a third of the book.

It is important to note that the ferry rocket von Braun described in "Man Will Conquer Space Soon" and Across the Space Frontier was not the one he wrote about in The Mars Project and unveiled at the Hayden Planetarium. Working closely with von Braun, artists Rolf Klep and Chesley Bonestell had transformed his stumpy 1948 design into a graceful tapered arrow that loomed silvery gray over its tropical island or sea-coast launch site. The 1952 design is presented in model form in this post courtesy of modeler and model historian Allen B. Ury (Fantastic Plastic: A Virtual Museum of Flying Wonders!).

Because he sought to sway non-specialist Americans, von Braun abandoned the metric system in his new ferry rocket description. In keeping with my policy of employing the measurement units used in my source materials, I will, too.+++inset-left

The cover of ACROSS THE SPACE FRONTIER captures the moment when the 1952 ferry rocket sheds its spent second stage, which then deploys a ringed-shaped steel-mesh parachute. The third stage, meanwhile, ignites five rocket motors to continue its climb to orbit. NASA.

The 1952 ferry rocket would have begun its voyage to Earth orbit and back within an enormous assembly building. Its three stages would have been stacked empty - that is, without propellants - atop a square mobile launch pad with a roughly 70-foot-diameter round hole at its center. The pad would have rested on four parallel tracks leading to the launch site, where propellant loading would take place. The tapered, finned first stage would have measured 65 feet across its base, stood 120 feet tall, and weighed 770 tons without propellants. The second stage, 44 feet in diameter at its base and 68 feet tall with an empty weight of 77 tons, would have been hoisted atop the first stage using cranes within the assembly building. The third stage, with a wingspan of 156 feet, would then have been positioned atop the second stage. The third stage would have measured 19 feet across its base, 77 feet from nose to tail, and had an empty weight of 78.5 tons. To avoid damage in the event of a launch accident, the assembly building would have been located several miles from the ferry rocket launch site. The 1952 ferry rocket would have stood 265 feet tall atop its launch pad as it crept along the four tracks leading to its launch site; that is, nearly 75 feet taller than its 1948 counterpart, or about the same height as a 24-story skyscraper. Upon arrival at the launch site, workers would have positioned the hole in the mobile launch pad above a subterranean exhaust tunnel designed to divert fire from the first-stage engines to an exhaust outlet a safe distance away from the rocket. They would then begin filling its tanks. The first stage would have held 5250 tons of hydrazine fuel and nitric acid oxidizer; the second stage, 770 tons; and the third, 90 tons. In all the stages, the oxidizer tank would have been mounted atop the fuel tank. Many modern launch vehicles opt for a few large motors over many small ones. Von Braun, for his part, opted for 51 rocket motors in his ferry rocket first stage, 34 in its second stage, and five in its third stage. He did this mainly to permit all three stages of his 1952 ferry rocket to use one type of motor, enabling cost-saving rocket motor mass production. Hydrogen peroxide stored in ring-shaped tanks located between the bottom of the propellant tanks and the top of the rocket motors on each stage would have been decomposed using a catalyst, yielding high-temperature steam that would have driven turbopumps. The turbopumps would have fed propellants into the rocket motors at a prodigious rate. Von Braun noted that the 51 first-stage motors, with a combined thrust of nearly 28 million pounds, would have drained the 5250 tons of propellants in the first stage tanks in just 84 seconds; that is, at a rate of about 61 tons per second. The second-stage motors, with a combined thrust of 1750 tons, would have expended their propellants in 124 seconds at a rate of 6.1 tons per second. The first stage would have climbed slowly at first, but by the time it shut down would have subjected the six-person ferry rocket crew, strapped safely into protective acceleration couches, to a maximum acceleration equal to nearly nine times the pull of Earth's gravity. The second stage would have subjected the crew to a maximum acceleration of about eight times the pull of Earth's gravity. The first stage would have shut down under guidance of an autopilot at an altitude of 24.9 miles, 31.1 miles down-range of the launch site, moving toward the north-east at a velocity of 5256 miles per hour. The ferry rocket would by this time have tipped from an ascent angle at liftoff of 90° (that is, straight up) to one of 20.5°. It would then have separated, clearing the way for the second-stage motors to ignite. After first-stage shutdown, the crew would have for a moment felt weightless. The second-stage engine would then have ignited, momentarily blasting a conical shield atop the first stage with fire before moving away rapidly bearing the third stage. Immediately after separation, the first stage would have deployed from its base a 217-foot-wide "ring-shaped ribbon parachute" made of steel mesh. At its deployment altitude, air resistance would be minimal, so stage and parachute would continue to coast upward to an altitude of about 40 miles before turning nose-down and falling toward the ocean. The conical blast shield would help to protect it from aerodynamic heating during descent. It would attain a descent velocity of 150 feet per second by the time it fell to 150 feet above the water. At that moment, small solid-propellant motors would have ignited and burned for two seconds, gently lowering the first stage into the sea 189 miles downrange of the launch site. A large recovery ship, pre-positioned to collect the stage, would soon have arrived. Von Braun envisioned it as a specialized "seagoing drydock," which would have filled on-board tanks with sea water to submerge, moved its drydock section under the bobbing first stage, then pumped seawater from its tanks to raise the stage clear of the ocean. The ship would then have set course for a special harbor close to the launch site where the first stage would be inspected, refurbished, and reused. The same harbor would, von Braun noted, serve ocean-going ships that would deliver thousands of tons of propellants to the launch site. The 1952 ferry rocket's second stage would have shut down 39.8 miles high and 332 miles downrange of the launch at a velocity of 14,364 miles per hour. By the time it separated from the third stage, it would have been tipped at a gentle angle of just 2.5°. After the third-stage motors blasted its top-mounted protective shield with fire, it would have deployed a 75-foot-diameter ring-shaped steel-mesh parachute. The second stage would have ignited solid-propellant braking motors and slipped into the water 906 miles down-range of the launch site just eight minutes after ferry rocket liftoff. A specialized recovery ship would then have closed in to collect the stage and transport it to the launch site harbor. The winged third stage - which would, in fact, have comprised von Braun's piloted orbital spaceship - would have fired its five engines under autopilot control for 84 seconds, burning about 65 tons of its 91.3-ton propellant load and subjecting its crew to acceleration equal to twice Earth's gravitational pull. The engines would have shut down 705 miles down-range of the launch site at an altitude of 63.3 miles after pushing the third stage to a velocity of 18,468 miles per hour. Momentum would have carried the third stage toward its operational altitude of 1075 miles, but the five rocket motors' work would have been far from done. The stage would have lost velocity as it climbed; in addition, its orbit about the Earth would have been elliptical, with a perigee of only 63.3 miles. To circularize its orbit and regain speed, the autopilot would have fired the motors for 15.4 seconds as the piloted stage reached apogee, expending 12.1 tons of the 26.3 tons of propellants left on board. This would have placed it into a 1075-mile-high circular orbit. The third stage and its 36 tons of cargo would have circled the Earth in exactly two hours moving at 15,840 miles per hour. Von Braun envisioned a ferry rocket fleet, the main goal of which would have been the assembly and resupply of a 250-foot-wide wheel-shaped space station in near-polar 1075-mile-high orbit. Von Braun thought that the ferry rocket fleet and station could be made operational in 1963 for a total cost of $4 billion. He estimated that perhaps a dozen ferry rocket flights would be needed to launch and assemble all the necessary space station components. After the station was completed, it would have served as the ferry rocket fleet's only destination in space. The ferry rockets would, however, never have touched the completed station. Von Braun proposed that piloted third stages inject into 1075-mile-high circular orbit at a safe distance from the station so that rocket motor firings could not damage it. In place of docking, pressurized space taxis would have transported crew and cargo between third stages and the station. After completing its orbital mission, the third stage would have turned under autopilot control using on-board momentum wheels to point its aft end in its direction of flight, then would have fired its five engines for 14.8 seconds. The maneuver, which would have occurred very nearly over the ferry rocket launch site, would have expended 5.7 tons of propellants to nudge the third stage into an elliptical orbit with a 49.7-mile perigee. The third stage would have coasted toward its perigee for 51 minutes. As it reached perigee halfway around the world from its landing site, it would have been moving at 18,500 miles per hour; that is, fast enough to ascend again to a 1075-mile-high apogee. To avoid this, the third stage would have used its wings to hold itself within Earth's atmosphere. It would have shed speed over a 13,650-mile glide-path. Aerodynamic heating would have boosted its surface temperature to 1350° F, causing it to glow cherry red. To deal with the heat, von Braun proposed to circulate coolant between the hull and the outer wall of the crew cabin. Clear coolant would also flow between panes of glass making up the pilot's canopy and viewports. The third stage would have slowed to the speed of sound (740 miles per hour) at an altitude of 14.9 miles. A short time later, the 29.7-ton glider would have extended its landing gear and touched down on a concrete runway a few miles from the launch site at just 65 miles per hour. "Man Will Conquer Space Soon" was the first in an eight-part series of Collier's space articles spread over about two years. On 9 March 1955, soon after the Collier's series ended, Walt Disney Studios aired Man In Space, the first in a series of educational films Disney produced in collaboration with von Braun and his colleagues Willy Ley and Ernst Stuhlinger. The film included an animated account of the first piloted sortie into Earth orbit.+++inset-left

In keeping with its relatively limited mission goals, Von Braun's 1955 Disney ferry rocket would have been smaller than its predecessors. Its barrel-shaped third stage would have included only a single rocket motor and been distinct from the delta-winged crew-carrying glider. The glider would have had no obvious cargo compartment, though it would have included an airlock for spacewalks and window-mounted instruments for astronomy and Earth observation experiments. These would have paved the way for telescopic Earth surveillance cameras and a large space telescope on the space station.

For Earth-atmosphere reentry, the 1955 Disney ferry rocket crew would have cast off the spent third stage and ignited a single rocket motor built into the glider's tail. Judging only by information presented in the film, it is not clear whether any part of the ferry rocket would have been recovered and reused. Von Braun's expansive vision had begun to contract as the reality of space travel moved ever nearer; within months of the premiere of Man In Space, the U.S. and Russia would declare that they would launch small science satellites during the International Geophysical Year set to begin on 1 July 1957.

References

Across the Space Frontier, Cornelius Ryan, editor, The Viking Press, New York, 1952.

The Mars Project (2nd edition), Wernher von Braun, The University of Illinois Press, Urbana, 1962.

Man In Space, Tomorrowland: Disney in Space and Beyond, Walt Disney Treasures DVD series, 2004.

Beyond Apollo chronicles space history through missions and programs that didn’t happen. It is a space history blog, not a blog devoted to current space policy. It is not meant to be in any way discouraging; rather, it is intended to inform and inspire. Comments are encouraged. Off-topic comments might be deleted.