A rocketplane is an aircraft that uses rocket engines for primary propulsion. Unlike conventional aircraft, which generate thrust by accelerating ambient air through jet engines or propellers, rocketplanes carry both fuel and oxidizer onboard and are therefore not dependent on atmospheric oxygen. This self-contained propulsion allows rocketplanes to operate at altitudes and speeds far beyond the reach of air-breathing engines, including flight above the atmosphere itself. Unlike expendable rockets, which are discarded after a single use, rocketplanes are designed to be recovered and reflown, combining the performance of a rocket with the reusability of an airplane.

The history of rocketplanes is not a collection of isolated experiments but a single continuous thread running from 1928 to the present day. Each vehicle in this history inherited knowledge from its predecessors and contributed knowledge to its successors. The connections are sometimes direct, as when a designer moved from one program to the next. They are sometimes indirect, as when captured hardware and documents were shipped across oceans by intelligence agencies. And they are sometimes adversarial, as when one nation built a vehicle specifically to counter or replicate what another nation had achieved. The thread is held together by technology transfer, espionage, and the institutional memory of engineers who spent entire careers advancing the state of the art.

For the mathematical foundations of rocket propulsion, orbital mechanics, and atmospheric flight dynamics, see the companion article Introduction to Space Studies.

Software Versions

# Date (UTC)
$ date -u "+%Y-%m-%d %H:%M:%S +0000"
2026-02-27 21:34:00 +0000

# OS and Version
$ uname -vm
Darwin Kernel Version 23.6.0: Mon Jul 29 21:14:30 PDT 2024; root:xnu-10063.141.2~1/RELEASE_ARM64_T6000 arm64

$ sw_vers
ProductName:		macOS
ProductVersion:		14.6.1
BuildVersion:		23G93

# Hardware Information
$ system_profiler SPHardwareDataType | sed -n '8,10p'
      Chip: Apple M1 Max
      Total Number of Cores: 10 (8 performance and 2 efficiency)
      Memory: 32 GB

# Shell and Version
$ echo "${SHELL}"
/bin/bash

$ "${SHELL}" --version | head -n 1
GNU bash, version 3.2.57(1)-release (arm64-apple-darwin23)

# Claude Code Installation Versions
$ claude --version
2.1.42 (Claude Code)

The German Pioneers

Lippisch Ente, 1928

The history of rocketplanes begins on 11 June 1928 at the Wasserkuppe, a mountain in central Germany that had served as a center for glider flying since the early 1920s. On that date, the glider pilot Fritz Stamer flew the Lippisch Ente, a tailless canard glider designed by Alexander Lippisch and fitted with two Sander black powder rockets. The name “Ente” is the German word for “duck,” a reference to the canard configuration in which the horizontal stabilizer is mounted ahead of the main wing. The canard layout is called “canard” in English and French because the French word for “duck” is “canard.”

Each Sander rocket produced approximately 200 newtons of thrust for about 30 seconds. Stamer fired them in sequence, completing a 1,500-meter circuit of the Wasserkuppe airstrip. This was the first rocket-powered piloted aircraft flight in history. A second flight attempted to fire both rockets simultaneously for greater thrust over a shorter period. One rocket exploded, punching holes in both wings and setting the aircraft on fire. Stamer brought the burning glider down from approximately 20 meters altitude and escaped without serious injury. The Ente burned beyond repair.

The flight was commissioned by Fritz von Opel as part of the Opel-RAK rocket program, a collaboration between von Opel, the rocket builder Friedrich Sander, and the Austrian rocket enthusiast Max Valier.

Opel RAK.1, 1929

Where the Ente was a modified sailplane, the Opel RAK.1 was the first aircraft designed and built specifically for rocket propulsion. Julius Hatry designed and constructed the airframe under commission from Fritz von Opel. On 30 September 1929, at Rebstock airfield near Frankfurt am Main, von Opel himself piloted the RAK.1 before a large crowd.

The aircraft carried 16 Sander solid-fuel rockets producing a combined thrust of approximately 7,800 newtons. Von Opel flew approximately 3.5 kilometers in 75 seconds, reaching an estimated top speed of 150 kilometers per hour. The landing was hard. A downward gust at the edge of the landing ground forced von Opel down at approximately 129 kilometers per hour. The landing skid broke and the cockpit floor was shaved away, leaving von Opel hanging by his safety belt. He emerged unscathed, but the aircraft was significantly damaged.

Shortly after this flight, the onset of the Great Depression ended the Opel rocket experiments. Von Opel left Germany before 1930.

Heinkel He 176, 1939

A full decade passed before the next major advance in rocketplane design. On 20 June 1939, the test pilot Erich Warsitz flew the Heinkel He 176, the first aircraft powered solely by a liquid-fueled rocket engine. The engine was the Walter HWK R I-203, which burned 82 percent hydrogen peroxide and produced 5,880 newtons of thrust for approximately 50 seconds.

The He 176 was a private venture by Ernst Heinkel, who had been exploring rocket propulsion through earlier tests on modified aircraft. Warsitz had previously flown test flights on rocket-equipped He 72 and He 112 airframes to demonstrate the viability of rocket propulsion.

On 3 July 1939, Warsitz demonstrated the He 176 for Adolf Hitler and senior military leadership. The demonstration included a dramatic moment when Warsitz miscalculated his engine shutdown, began descending rapidly, then restarted the engine just before hitting the ground and performed a near-vertical climb. Despite this spectacle, the Reichsluftfahrtministerium cancelled the program on 12 September 1939, judging the aircraft too small and its performance unimpressive relative to conventional fighters. The single airframe was transferred to the Deutsche Luftfahrtsammlung in Berlin, where it was destroyed in an Allied bombing raid in 1943.

DFS 194, 1940

While Heinkel pursued the He 176 as a private venture, Alexander Lippisch continued developing his tailless swept-wing designs at the Deutsche Forschungsanstalt fur Segelflug, the German Institute for Sailplane Flight. On 2 January 1939, Lippisch and his entire team were transferred to the Messerschmitt company under the code name “Project X” to develop a rocket-powered interceptor.

The DFS 194 was a tailless aircraft originally designed with a piston engine. The airframe was modified to accept the Walter R I-203 rocket motor, the same engine type used in the He 176. In August 1940, at Peenemunde-West, the test pilot Heini Dittmar flew the DFS 194 under rocket power, reaching 550 kilometers per hour and exceeding the speed of the He 176.

The DFS 194 proved that Lippisch’s tailless swept-wing configuration was safe and effective at high speeds. It served as the direct aerodynamic precursor to the Messerschmitt Me 163 Komet, which scaled up the same design philosophy for operational combat.

Operational Rocketplanes of World War II

Messerschmitt Me 163 Komet

The Messerschmitt Me 163 Komet was the only rocket-powered fighter aircraft to achieve operational combat status in the history of aviation. Its lineage ran directly from the Lippisch Ente of 1928 through the DFS 194 of 1940, making it the culmination of over a decade of tailless swept-wing rocketplane research.

The production Me 163B was powered by the Walter HWK 109-509A-2 bipropellant rocket engine, which produced 16,670 newtons of thrust. The engine burned T-Stoff, concentrated hydrogen peroxide used as the oxidizer, and C-Stoff, a mixture of hydrazine hydrate and methanol used as the fuel. These propellants were hypergolic, meaning they ignited spontaneously on contact. Both were also extremely corrosive and toxic, and fuel leaks caused numerous fatal ground accidents throughout the program.

The Me 163 carried approximately 1,650 liters of propellant, providing 7.5 to 8 minutes of powered flight. This was sufficient for a climb to the service ceiling of 12,100 meters in approximately 3.5 minutes, followed by one or two high-speed passes through an Allied bomber formation before the pilot glided back to base unpowered. The aircraft was armed with two 30-millimeter MK 108 cannon.

On 2 October 1941, Heini Dittmar flew the Me 163A V4 to 1,004.5 kilometers per hour, becoming the first pilot to exceed 1,000 kilometers per hour. This record was not officially surpassed until 1947. On 6 July 1944, Dittmar reached an unofficial 1,130 kilometers per hour in the Me 163B V18.

Jagdgeschwader 400, the operational unit assigned to fly the Me 163, was formed on 1 February 1944 at Brandis airfield. The first combat sortie occurred on 28 July 1944. Over the course of the war, the Me 163 achieved 9 confirmed aerial kills while suffering 14 aircraft losses, of which approximately 10 were in combat and the remainder from accidents and landing crashes. About half of all losses occurred during unpowered landing approaches, when the aircraft was at its most vulnerable. Allied fighter pilots learned to wait for the Komet to exhaust its fuel and then attack during the glide.

Approximately 370 Me 163s were produced. Only 279 entered service. Jagdgeschwader 400 was disbanded in April 1945, and surviving pilots were transferred to Me 262 jet fighter units. The Me 163 demonstrated both the extraordinary potential and the severe practical limitations of rocket-powered combat aircraft.

Bachem Ba 349 Natter

The Bachem Ba 349 Natter represented a fundamentally different approach to rocket-powered interception. Where the Me 163 was a sophisticated fighter requiring trained pilots and prepared airfields, the Natter was a semi-expendable vertical-launch interceptor designed to be operated by minimally trained personnel from concealed forest clearings.

Designed by Erich Bachem, the Natter was launched vertically from a guide rail using four Schmidding SG34 solid-fuel boosters producing 47,000 newtons of combined thrust for 10 seconds. After booster separation, the main Walter HWK 109-509A-1 engine, the same type used in the Me 163, sustained flight. The pilot would aim at a bomber formation, fire a salvo of 24 unguided rockets from the nose, and then bail out. A separate parachute would recover the rear fuselage containing the Walter engine for reuse.

On 1 March 1945, the test pilot Lothar Sieber made the first and only crewed vertical takeoff flight. At approximately 500 meters altitude, the cockpit canopy came loose. The headrest was attached to the underside of the canopy, and when it separated, Sieber’s head was pulled backward under three times the force of gravity. Erich Bachem concluded that Sieber likely pulled the control column backward involuntarily. The Natter entered an uncontrolled trajectory and crashed, killing Sieber at the age of 22. He became the first person to launch vertically under rocket power.

Thirty-six Natters were produced by the war’s end. Twenty-five were used in unmanned test flights. None entered operational combat. The program stands as a measure of the desperation that characterized the final months of the war.

Yokosuka MXY-7 Ohka

The Yokosuka MXY-7 Ohka was a rocket-powered piloted weapon developed by the Imperial Japanese Navy independently of any German rocketplane program. The Ohka, whose name means “Cherry Blossom,” was designed at the Yokosuka Naval Air Technical Arsenal based on a concept by Ensign Mitsuo Ohta.

The aircraft carried three Type 4 Mark 1 Model 20 solid-fuel rocket motors, each producing 2,616 newtons of thrust for 8 to 10 seconds. In the nose sat a 1,200-kilogram warhead. The Ohka was carried to altitude beneath a Mitsubishi G4M “Betty” bomber and released within range of Allied naval vessels. After release, the pilot would ignite the rockets and dive into the target at speeds reaching 1,040 kilometers per hour.

The first combat deployment on 21 March 1945 was a complete failure. The G4M mother ships were intercepted by Allied fighters before reaching release range and were forced to jettison their Ohkas prematurely. The first successful strike came on 12 April 1945, when an Ohka sank the destroyer USS Mannert L. Abele near Okinawa. Over the course of the Okinawa campaign, Ohka attacks sank or damaged beyond repair three Allied ships.

Seven hundred and fifty-five operational Ohkas were produced. Postwar analysis concluded that the weapon’s impact was negligible, primarily because the slow, heavily laden G4M mother ships were extremely vulnerable to interception before reaching release range.

Bereznyak-Isayev BI-1

The Bereznyak-Isayev BI-1 was the Soviet Union’s first rocket-powered aircraft, developed under wartime urgency following Operation Barbarossa. Designed by Alexander Bereznyak and Alexei Isayev under the supervision of Viktor Bolkhovitinov, the BI-1 was powered by the Dushkin D-1A-1100 liquid-fueled rocket engine. The engine burned tractor kerosene and red fuming nitric acid and was expected to produce 10,800 newtons at full power.

On 15 May 1942, the test pilot Grigory Bakhchivandzhi flew the BI-1 under rocket power for the first time. The engine had been de-rated to 4,900 newtons for safety. Bakhchivandzhi reached an altitude of 840 meters and a maximum speed of 400 kilometers per hour in a flight lasting 3 minutes and 9 seconds.

On 27 March 1943, during his seventh flight in the type, Bakhchivandzhi was killed when the BI-3 prototype entered a 45-degree dive and crashed. The cause was not understood at the time. Later wind tunnel testing revealed the phenomenon of transonic pitch-down, in which high-speed aerodynamic effects created an uncontrollable nose-down pitching moment on the stabilizers.

Seven BI prototypes were constructed. A total of 12 powered flights were recorded. Bereznyak went on to found OKB-155, which became a leading cruise missile design bureau. Isayev founded OKB-2, specializing in liquid-propellant rocket engines for spacecraft and launch vehicles. In 1973, Bakhchivandzhi was posthumously elevated to Hero of the Soviet Union.

Technology Transfer and Espionage

Operation Paperclip

The defeat of Nazi Germany in 1945 triggered a race among the Allied powers to capture German aerospace engineers and their research. Operation Paperclip was the American program that brought German scientists and engineers to the United States to continue their work under American direction.

Among the rocketplane-specific captures, Alexander Lippisch was brought to the United States and assigned to Wright Field. After his initial assignment ended in 1946, he joined the Naval Air Materiel Center in Philadelphia, remaining until 1950. His captured DM-1 delta-wing glider was shipped to the National Advisory Committee for Aeronautics, or NACA, at Langley for full-scale wind tunnel testing. The data from these tests influenced the development of the Convair XF-92A, the first jet-propelled delta-wing aircraft to fly.

Walter Dornberger, who had led the V-2 rocket program at Peenemunde, joined Bell Aircraft Corporation in 1950 and rose to vice president. At Bell, Dornberger proposed the Bomber-Missile concept in 1952 with Krafft Ehricke, a vertical-launch boost-glide vehicle directly descended from the wartime Silbervogel concept. Dornberger also played a major role in the development of the North American X-15 and served as a key consultant for the Boeing X-20 Dyna-Soar. His career at Bell, which lasted until 1965, represents one of the clearest examples of direct technology transfer from German wartime rocketplane research to American postwar programs.

Five captured Me 163 airframes were shipped to the United States. Unpowered glide tests were conducted at Muroc dry lake beginning 3 May 1946, with Me 163 airframes towed to altitude behind Boeing B-29 aircraft. Lippisch himself participated in the tests and discovered wing delamination, which led to the cancellation of planned powered flight tests. Walter HWK 109-509 engine documentation captured at the Walter factory provided detailed information on bipropellant rocket engine design, variable-thrust control, and the use of hydrogen peroxide as an oxidizer.

Operation Osoaviakhim

On the Soviet side, the capture of German aerospace expertise took a different and more coercive form. During the night of 21 to 22 October 1946, Operation Osoaviakhim forcibly relocated approximately 2,500 German specialists along with nearly 3,800 family members from the Soviet occupation zone of Germany to facilities across the Soviet Union. The operation was decreed on 13 May 1946 under Council of Ministers resolution number 1017-419 and was carried out by MVD and Soviet Army units under the Soviet Military Administration in Germany.

The captured specialists included experts in rocketry, aviation, and optics. The Soviet Ministry of Aviation Industry acquired approximately 3,558 aviation experts through this and related programs, enabling the transfer of swept-wing design, turbomachinery expertise, and rocket engine technology. German engineers adapted Me 163 rocket interceptor data for Soviet air-to-surface missile prototypes. Captured Me 163 airframes, Walter engine components, and swept-wing aerodynamic data all contributed to Soviet postwar aviation development.

For the broader context of German rocket technology capture, including the parallel effort to acquire V-2 ballistic missile expertise, see Introduction to Space Studies.

The Silbervogel Concept

Not all technology transfer involved the physical capture of hardware and personnel. The Silbervogel, or “Silver Bird,” was a suborbital antipodal bomber concept developed by Eugen Sanger and Irene Bredt in the late 1930s and early 1940s. The vehicle was never built, but the idea proved to be one of the most influential rocketplane concepts of the twentieth century.

Sanger and Bredt proposed a liquid-propellant rocket-powered vehicle capable of Mach 10 at altitudes exceeding 160 kilometers. The aircraft would be launched from a rocket-powered sled and then skip along the upper atmosphere in a series of suborbital hops, using the fuselage as a lifting body to generate lift during each atmospheric encounter. The final version of their research was published in 1944 as a classified report titled “A Rocket Drive for Long-Range Bombers.” Approximately 100 copies were produced.

Soviet intelligence discovered copies of the Sanger-Bredt report at Peenemunde. A condensed version reached Stalin. In November 1946, the NII-1 research institute was formed under the mathematician Mstislav Keldysh to evaluate the concept. In 1947, the Keldysh team concluded that the high fuel consumption of Sanger’s rocket-based design made the concept impracticable in the short term but proposed an alternative using a combined ramjet and rocket propulsion system. This analysis would later influence the design of the MiG-105 Spiral spaceplane in the 1960s.

On the American side, Dornberger used the Silbervogel concept as the basis for his Bomber-Missile proposal at Bell Aircraft. Research at Bell showed that the atmospheric skip-glide technique was less practical than anticipated, leading to the boost-glide approach that eventually became the Boeing X-20 Dyna-Soar. The Silbervogel concept thus influenced both superpowers’ spaceplane programs for decades after its authors had moved on to other work.

The American X-Plane Program

Bell X-1, 1947

On 14 October 1947, Captain Charles “Chuck” Yeager flew the Bell X-1 to Mach 1.06 at an altitude of 13,100 meters, becoming the first pilot to exceed the speed of sound in controlled level flight. The aircraft, serial number 46-062, was nicknamed “Glamorous Glennis” after Yeager’s wife.

The X-1 was powered by the Reaction Motors XLR11-RM-3, a four-chamber liquid-fueled rocket engine producing 26,700 newtons of thrust. The aircraft was air-launched from the bomb bay of a Boeing B-29 Superfortress at 6,100 meters above Rogers Dry Lake at Edwards Air Force Base in California.

The Bell X-1 established the template for the entire X-plane program. It demonstrated that a purpose-built rocket-powered research aircraft, air-launched from altitude and recovered on a dry lakebed, could systematically explore flight regimes that were inaccessible to conventional aircraft. Every subsequent X-plane followed this basic operational pattern.

Bell X-1A and X-1B

The X-1A and X-1B extended the original X-1 design to higher speeds and new research objectives. On 12 December 1953, Yeager flew the X-1A to Mach 2.44 at an altitude of 22,800 meters. Shortly after reaching peak speed, the aircraft experienced inertia coupling, a phenomenon not yet fully understood at the time, and entered a violent spin. The X-1A dropped from maximum altitude to 7,600 meters, subjecting Yeager to accelerations of up to 8 g. He struck and cracked the canopy with his helmet before regaining control.

The X-1B contributed a different but equally important advance. In November 1957, NACA technicians installed reaction control jets on the X-1B, making it the first aircraft to fly with a reaction control system. Small rocket thrusters provided directional control independent of aerodynamic surfaces, a capability essential for flight at altitudes where the atmosphere is too thin for conventional control surfaces to function. The test pilot Neil Armstrong made three flights to evaluate the reaction control system’s performance. Cracks in the fuel tanks forced the X-1B’s retirement in 1958 after 27 flights. The reaction control research then shifted to the Lockheed F-104 Starfighter and subsequently informed the X-15’s control system design.

Douglas D-558-2 Skyrocket, 1953

On 20 November 1953, the NACA research pilot A. Scott Crossfield flew the Douglas D-558-2 Skyrocket to Mach 2.005 at 18,900 meters, becoming the first pilot to exceed Mach 2.

The Skyrocket was notable for its mixed propulsion system. It carried both a Westinghouse J34-WE-40 turbojet producing 13,300 newtons of thrust for takeoff, climb, and landing, and a Reaction Motors LR8-RM-6 four-chamber rocket engine producing 26,700 newtons of thrust for high-speed research. For the Mach 2 flight, the Skyrocket was air-launched from a Navy P2B-1S Superfortress at 9,800 meters. Crossfield fired the rocket engine, climbed to 22,000 meters, entered a shallow dive, passed Mach 2 at 18,900 meters, and then made an unpowered dead-stick landing on the dry lakebed at Edwards Air Force Base.

Bell X-2 Starbuster, 1956

The Bell X-2 Starbuster was designed to explore flight at speeds beyond Mach 2 and to investigate the aerodynamic heating and stability challenges that emerged at higher velocities. It was powered by the Curtiss-Wright XLR25, a two-chamber throttleable liquid-fueled rocket engine with variable thrust ranging from 11,100 to 66,700 newtons.

On 27 September 1956, Captain Milburn “Mel” Apt flew the X-2 to Mach 3.196 at 19,960 meters, becoming the first pilot to exceed Mach 3. This was Apt’s first and only X-2 flight. The engine burned 15 seconds longer than planned, carrying the aircraft well beyond the intended maximum of Mach 2.8. After reaching Mach 3.196, Apt initiated a banking turn while still above Mach 3. The aircraft experienced inertia coupling and tumbled uncontrollably. Apt ejected using the aircraft’s encapsulated cockpit escape system but was briefly knocked unconscious and was unable to bail out of the capsule before it struck the ground. He was killed.

The X-2 program demonstrated that aerodynamic heating and stability at Mach 3 and above presented challenges qualitatively different from those encountered at lower speeds. These lessons directly informed the thermal protection and stability augmentation systems designed into the X-15.

North American X-15 and X-15A-2

The North American X-15 was the most ambitious and most productive rocketplane ever built. Over a nine-year program running from 8 June 1959 to 24 October 1968, three X-15 aircraft made 199 free flights carrying 12 pilots, systematically exploring the hypersonic flight regime from Mach 4 to Mach 6.7 and from the upper atmosphere to altitudes above 100 kilometers.

The X-15 was powered by the Reaction Motors XLR99, the first large throttleable, restartable human-rated rocket engine. It produced 253,500 newtons of thrust at vacuum and burned liquid oxygen and anhydrous liquid ammonia. The first 24 flights used two XLR11 engines before the XLR99 was ready, with the new engine installed beginning November 1960.

On 3 October 1967, Major William “Pete” Knight flew the X-15A-2 to Mach 6.7 at 31,120 meters, setting the speed record for a crewed, powered, controlled aircraft that stands to this day. The X-15A-2 was the number two airframe rebuilt after an emergency landing. It featured a 71-centimeter fuselage extension, two external drop tanks adding 25,900 kilograms of propellant and providing 60 seconds of additional engine burn, and an ablative heat shield coating.

On 22 August 1963, the NASA research pilot Joseph Walker flew the X-15 to 107,960 meters, crossing the Karman line at 100 kilometers altitude and becoming the first person to enter space twice. He remained weightless for approximately five minutes.

Eight X-15 pilots flew above 80,500 meters, the 50-mile altitude that qualified them as astronauts under the United States definition. Five were Air Force pilots who received military astronaut wings at the time. Three were NASA civilian pilots who received astronaut wings retroactively in 2005. Among them was Michael Adams, who was killed on 15 November 1967 when his X-15 entered a violent Mach 5 spin at 70,100 meters. The aircraft broke apart when aerodynamic forces exceeded design limits during descent through the lower atmosphere.

The X-15 program bridged the era of atmospheric rocket-powered research aircraft and the era of orbital spaceplanes. Its data on hypersonic aerodynamics, thermal protection, reaction control systems, and human factors at extreme altitudes directly informed the design of every subsequent American reentry vehicle, including the Space Shuttle.

Boeing X-20 Dyna-Soar

The Boeing X-20 Dyna-Soar was designed as an orbital spaceplane capable of launching vertically atop a Titan rocket, maneuvering in orbit, and returning to a runway landing. The program represented the most direct descendant of the Silbervogel concept, pursued through Walter Dornberger’s influence at Bell Aircraft and subsequently at Boeing after Boeing won the prime contract in June 1959.

The X-20 was cancelled on 10 December 1963 by Secretary of Defense Robert McNamara, who cited escalating costs, uncertainty over the launch vehicle, and a lack of clearly defined mission. The program had suffered from persistent conflict between the Air Force and NASA’s Mercury and Apollo programs over the role of crewed military spaceflight. Funding was redirected to the Manned Orbiting Laboratory.

Although the X-20 never flew, its cancellation had significant consequences. It prompted the Soviet Union to initiate the MiG-105 Spiral spaceplane program. It also advanced the state of the art in thermal protection, reentry guidance, and boost-glide trajectory planning, all of which contributed to the Space Shuttle design a decade later.

Martin X-24A and X-24B

The Martin X-24A and X-24B were lifting body research vehicles designed to test whether a wingless vehicle shape could generate sufficient aerodynamic lift to make a controlled runway landing after reentry from orbit.

The X-24A had a bulbous teardrop shape with no conventional wings. It was 7.5 meters long and 3.5 meters wide, powered by the XLR11 rocket engine, and drop-launched from a modified B-52 Stratofortress. It completed 28 flights, reaching a maximum speed of 1,667 kilometers per hour and a maximum altitude of 21,800 meters.

The X-24B was created by returning the X-24A to Martin Marietta for modification into a new shape. The rebuilt vehicle featured a rounded top, a flat bottom, and a double delta planform with a pointed nose. It completed 36 flights, reaching 1,873 kilometers per hour and 22,600 meters.

On 5 August 1975, the NASA test pilot John Manke flew the X-24B from altitude to an unpowered precision landing on the main concrete runway at Edwards Air Force Base. This was the first unpowered landing of a lifting body on a conventional runway. The demonstration was pivotal. It convinced NASA engineers that the Space Shuttle orbiter could land unpowered, directly leading to the elimination of jet engines that had originally been planned for Shuttle landing approaches.

The Soviet Response

MiG-105 Spiral

The MiG-105 Spiral was the Soviet Union’s direct response to the American X-20 Dyna-Soar. Work on the Spiral aerospace system began formally in 1965, two years after the Dyna-Soar’s cancellation. The Soviet Air Force tasked the Mikoyan design bureau under chief designer Gleb Lozino-Lozinsky, with official authorization granted on 26 June 1966.

The Spiral concept differed significantly from the Dyna-Soar’s expendable-rocket launch profile. Soviet engineers proposed an air-launched system in which a spaceplane and booster stage would be released at high altitude from a large hypersonic mothership. The spaceplane featured a variable-geometry wing for atmospheric flight after reentry.

The project was halted in 1969 and briefly resurrected in 1974 in response to the United States Space Shuttle program. A subscale atmospheric test vehicle, the MiG-105-11, conducted eight subsonic free-flight tests between October 1976 and September 1978 at Zhukovsky Air Base near Moscow. All flights were piloted by the test pilot Aviard Fastovets. The first crewed drop test occurred on 11 October 1976 from a modified Tu-95K bomber. The final flight in September 1978 ended in a hard landing that damaged the prototype.

The Spiral project was officially terminated in 1978 when the decision was made to concentrate resources on the Buran program instead. Data and experience from the MiG-105 contributed to the Buran shuttle’s design, most notably through the BOR-4 subscale orbital test vehicles, which were related to the Spiral program’s lifting body research.

In an ironic twist of intelligence history, the BOR-4 was photographed by Western intelligence agencies during recovery operations in the Indian Ocean in 1983. Researchers at NASA Langley Research Center reverse-engineered scale models from these photographs and tested them in wind tunnels, producing the HL-20 lifting body concept. The HL-20 eventually became the basis for Sierra Space’s Dream Chaser, a vehicle discussed later in this article. Soviet intelligence thus informed American designs just as American intelligence had informed Soviet ones.

Buran

The Buran program was the Soviet Union’s response to the American Space Shuttle. At 03:00:02 UTC on 15 November 1988, the Buran orbiter launched from Baikonur Cosmodrome atop an Energia super-heavy lift rocket, completed two orbits of the Earth in 3 hours and 25 minutes, and performed a fully automated landing at the shuttle runway at Baikonur. The flight was entirely uncrewed. No American Space Shuttle ever performed a fully automated landing.

The Buran program was accompanied by one of the most extensive aerospace espionage campaigns of the Cold War. By the time the American Shuttle first launched in April 1981, the KGB had acquired over 3,000 documents related to the Shuttle program, including approximately 300 related to wind tunnel tests, 100 on solid rocket boosters, and others on computer systems and military applications. Much of the material was unclassified, obtained from the Government Printing Office and NASA-funded contractor studies.

Despite the external visual similarity to the Space Shuttle, the Buran incorporated fundamental design differences that reflected independent Soviet engineering decisions. The main engines were located on the Energia rocket rather than on the orbiter, meaning the expensive engines were expended with each launch but also allowing the Energia to serve as an independent heavy-lift vehicle. The orbiter carried ejection seats for the crew. Most significantly, the Buran was designed from the outset for fully autonomous flight, including uncrewed orbital operations and automated landing. These differences suggest that espionage primarily informed the external aerodynamic configuration, while the propulsion architecture, avionics, and operational philosophy were developed independently.

The Buran program was officially terminated on 30 June 1993 following the dissolution of the Soviet Union and the resulting collapse in funding. Approximately 20 billion rubles had been spent on the program. On 12 May 2002, the hangar roof at Baikonur Cosmodrome collapsed, destroying the Buran orbiter that had flown in 1988 along with a mockup of an Energia booster and killing eight workers.

The Space Shuttle

The Space Shuttle was the largest and most complex rocketplane ever flown. Over 30 years of operations from 12 April 1981 to 21 July 2011, the Shuttle fleet completed 135 missions, carrying 355 astronauts from 16 countries. Five operational orbiters were built. Columbia flew first in 1981. Challenger entered service in 1983. Discovery began flying in 1984. Atlantis followed in 1985. Endeavour was built in 1991 as a replacement for Challenger.

The Shuttle’s place in rocketplane history is defined by the programs that preceded it. The X-15 provided hypersonic flight data, thermal protection research, and reaction control system experience that directly informed the Shuttle’s reentry profile. The lifting body program, culminating in the X-24B’s unpowered runway landing in 1975, demonstrated that a winged orbiter could glide to a conventional landing without air-breathing engines. The X-20 Dyna-Soar, although cancelled before flying, established the concept of a piloted winged orbital vehicle with conventional runway recovery. The X-1B’s reaction control system work informed the Shuttle’s attitude control design.

The loss of Challenger on 28 January 1986, 73 seconds after launch due to the failure of an O-ring seal in the right solid rocket booster, killed all seven crew members. The loss of Columbia on 1 February 2003, which broke apart during reentry after a piece of insulating foam breached the leading edge of the left wing’s thermal protection system, killed another seven. The Columbia Accident Investigation Board concluded that NASA had failed to learn many of the organizational lessons from the Challenger disaster.

These losses profoundly influenced the subsequent direction of spaceflight. After Challenger, NASA removed commercial satellite payloads from the Shuttle manifest and redirected them to expendable launch vehicles. After Columbia, the decision was made to retire the Shuttle fleet entirely. Crew transport to the International Space Station shifted first to Russian Soyuz vehicles and later to commercially operated spacecraft. Both disasters accelerated the broader trend toward separating crew transport from cargo delivery and toward greater use of uncrewed vehicles.

The Modern Era

SpaceShipOne, 2004

On 21 June 2004, the test pilot Mike Melvill flew SpaceShipOne to an altitude of 100,124 meters, completing the first privately funded crewed spaceflight in history. The vehicle was designed by Burt Rutan of Scaled Composites and funded by Microsoft co-founder Paul Allen, who invested approximately 25 million dollars.

SpaceShipOne was carried to approximately 15,000 meters by White Knight, a custom turbofan-powered carrier aircraft, and then released for a rocket-powered climb. The hybrid rocket motor burned a mixture of nitrous oxide and rubber, providing approximately 76 seconds of thrust.

SpaceShipOne introduced the “feathered” reentry technique, in which the rear half of the wings and twin tail booms folded upward approximately 70 degrees along a hinge. This increased drag and provided inherent aerodynamic stability during reentry, functioning like a badminton shuttlecock. The system removed most of the need to actively control attitude during early reentry. After deceleration, the pilot retracted the feather and glided to a conventional runway landing.

SpaceShipOne won the Ansari X Prize, a 10-million-dollar competition requiring a non-government organization to launch a reusable crewed spacecraft above 100 kilometers twice within two weeks. Mike Melvill flew the first qualifying flight to 102,900 meters on 29 September 2004. Brian Binnie flew the second to 112,000 meters on 4 October 2004, surpassing the X-15’s altitude record. The prize was won on the 47th anniversary of the launch of Sputnik 1.

SpaceShipTwo and Virgin Galactic

SpaceShipTwo was the commercial successor to SpaceShipOne, designed to carry six passengers on suborbital spaceflights for Richard Branson’s Virgin Galactic. The vehicle used the same feathered reentry concept but was significantly larger and was carried to altitude by a purpose-built twin-fuselage carrier aircraft called WhiteKnightTwo.

On 31 October 2014, the first SpaceShipTwo vehicle, VSS Enterprise, suffered a catastrophic in-flight breakup during a powered test flight and crashed in the Mojave Desert. Co-pilot Michael Alsbury was killed. Pilot Peter Siebold was seriously injured but survived. The National Transportation Safety Board determined that the breakup was caused by Alsbury’s premature unlocking of the feathering mechanism. Contributing factors included the absence of a mechanical inhibit preventing premature feather unlock and insufficient pilot training on the unlock procedure.

A second vehicle, VSS Unity, completed the first commercial flight on 29 June 2023, designated Galactic 01. Virgin Galactic subsequently retired the vehicle after completing several additional commercial flights.

Blue Origin New Shepard

Blue Origin’s New Shepard represents a fundamentally different design philosophy from the winged rocketplanes discussed throughout this article. New Shepard is a vertical-takeoff, vertical-landing suborbital system consisting of a reusable booster rocket and a detachable crew capsule. The capsule has no wings, no aerodynamic control surfaces, and returns to Earth under parachutes rather than gliding to a runway.

The first crewed flight occurred on 20 July 2021, the 52nd anniversary of the Apollo 11 Moon landing. The crew included Blue Origin founder Jeff Bezos, his brother Mark Bezos, the Mercury 13 pilot Wally Funk who at age 82 became the oldest person to fly in space at that time, and the Dutch student Oliver Daemen who at age 18 became the youngest.

New Shepard is included in this history not as a rocketplane but as a point of contrast. Its capsule-on-a-rocket architecture represents an alternative evolutionary path for suborbital crewed spaceflight, one that prioritizes simplicity and autonomy over the aerodynamic sophistication of winged reentry vehicles.

Boeing X-37B

The Boeing X-37B is an uncrewed orbital spaceplane that carries the X-plane designation, placing it directly in the lineage that began with the Bell X-1 in 1947. The program originated as a NASA project in 1999, was transferred to the Defense Advanced Research Projects Agency, or DARPA, in 2004, and subsequently to the Air Force when NASA determined that the uncrewed reusable spacecraft did not align with its exploration objectives. The vehicle is now operated by the United States Space Force.

The X-37B is a 120-percent scaled derivative of the earlier Boeing X-40, built as part of the Air Force’s Space Maneuver Vehicle program. It launches vertically atop an expendable rocket, operates in orbit for extended durations, and returns to a conventional runway landing.

The first orbital mission launched on 22 April 2010. Since then, mission durations have grown progressively. The sixth mission, launched in 2020, set the endurance record at 908 days in orbit. All X-37B missions are classified.

The X-37B represents the application of the X-plane tradition to autonomous orbital operations. It demonstrates that a lifting body spaceplane can operate entirely without a crew, conducting long-duration orbital missions and returning to a precision runway landing under automated control.

Dream Chaser

Dream Chaser, developed by Sierra Space, traces its lifting body design directly to the HL-20 Personnel Launch System studied at NASA Langley Research Center in the late 1980s and 1990s. The HL-20 was itself based on the Soviet BOR-4 subscale orbital test vehicle that Western intelligence agencies photographed in 1983. The broader lifting body heritage extends through over 20,000 hours of research and testing, including the X-20 Dyna-Soar, the M2-F2, M2-F3, HL-10, X-24A, X-24B, and X-23 PRIME vehicles.

Dream Chaser was selected under NASA’s Commercial Resupply Services 2 contract to deliver cargo to the International Space Station. The vehicle is designed to be reusable for up to 15 missions and can land on conventional runways. As of late 2025, the first demonstration flight has been delayed to no earlier than late 2026.

Dream Chaser’s design lineage embodies the circular nature of rocketplane technology transfer. Soviet intelligence about the American Shuttle informed the Buran program. The Spiral program’s BOR-4 test vehicle, photographed by Western intelligence, informed the HL-20 at NASA Langley. The HL-20 became Dream Chaser. Three decades of intelligence and counter-intelligence thus contributed to a commercial cargo vehicle intended to serve an international space station operated jointly by nations that were once adversaries.

Dawn Mk-II Aurora

The Dawn Mk-II Aurora, developed by Dawn Aerospace in New Zealand and the Netherlands, represents the newest generation of rocketplanes. On 12 November 2024, the Aurora broke the sound barrier on its 57th flight, reaching Mach 1.1 and an altitude of 25,000 meters. It became the first aircraft designed and manufactured in New Zealand to exceed the speed of sound.

The Aurora is an uncrewed, remotely piloted vehicle with a wingspan of approximately 4 meters and a dry weight of approximately 399 kilograms. It is powered by a rocket engine burning 90 percent hydrogen peroxide and kerosene. The vehicle takes off from and lands on conventional runways as short as 1,000 meters, and the company has demonstrated a turnaround time of approximately six hours between flights.

The significance of the Aurora lies not in its speed or altitude, which are modest by rocketplane standards, but in its operational tempo. Where every rocketplane in this history required days or weeks of preparation between flights, the Aurora is designed for routine, rapid-turnaround operations from conventional airports. Commercial payload flights to 100 kilometers are projected to begin in 2027.

Conclusion

The history of rocketplanes is a single narrative thread spanning nearly a century. It begins with Fritz Stamer firing two black powder rockets on a modified sailplane in 1928 and continues through autonomous orbital vehicles and commercially operated spaceplanes today.

Five themes weave through this narrative. The first is the German pioneering work of the 1920s through the 1940s, in which Lippisch, Sander, Opel, Heinkel, Walter, and Messerschmitt established the fundamental design vocabulary of rocket-powered flight. The second is technology capture and espionage, through which Operation Paperclip and Operation Osoaviakhim transferred German expertise to both superpowers, and through which the Silbervogel concept independently influenced American and Soviet spaceplane programs for decades. The third is the systematic American X-plane program, in which each vehicle built directly on the achievements and failures of its predecessor, progressing methodically from Mach 1 in 1947 to Mach 6.7 in 1967. The fourth is the state-level pinnacle of the Space Shuttle and Buran, the largest and most complex rocketplanes ever built, which demonstrated both the possibilities and the costs of large-scale government spaceplane programs. The fifth is the modern era of privatization, in which commercial companies are pursuing rocketplane technology with fundamentally different cost structures, operational models, and risk tolerances than the government programs that preceded them.

Connecting all five themes is the continuous thread of institutional knowledge and individuals. Lippisch’s tailless designs led to the Me 163. Dornberger moved from V-2 to Bell Aircraft to the X-15 and Dyna-Soar. The X-15’s data informed the Shuttle. Soviet photographs of American hardware informed Buran. Western photographs of Soviet hardware informed Dream Chaser. At every transition, the knowledge accumulated by one program became the foundation for the next.

The convergence of reusable vehicles, autonomous systems, and commercial operations in the modern era suggests that the century-long arc of rocketplane development is entering a new phase. The fundamental engineering challenges of rocket-powered atmospheric and orbital flight have been solved. The remaining challenge is to make routine what was once extraordinary.

Future Reading

  • Smithsonian National Air and Space Museum, extensive historical collections and editorial resources on the history of flight, including detailed artifact pages for many of the vehicles discussed in this article.

  • NASA Armstrong Flight Research Center, the primary United States facility for atmospheric flight research and the operational base for the X-1, X-2, X-15, lifting body, and X-37B programs.

  • The Right Stuff by Tom Wolfe, a narrative account of the early X-plane era and the selection of the Mercury Seven astronauts, centered on Edwards Air Force Base and the test pilots who flew the X-1, X-2, and X-15.

  • X-15 Research Results, NASA Special Publication SP-60, a comprehensive technical summary of the aerodynamic, structural, thermal, and handling qualities data obtained from the X-15 flight program.

  • Buran — The Soviet Shuttle, the Smithsonian National Air and Space Museum editorial resource on the Buran program, covering its development, flight, and relationship to the American Space Shuttle.

References