Steve Austin, astronaut. A man barely alive.

Gentlemen, we can rebuild him. We have the technology.

We have the capability to make the world’s first bionic man.

Steve Austin will be that man, better than he was before.

Better, stronger, faster.

So goes the iconic opening of the classic 1970s television series The Six Million Dollar Man, starring Lee Majors as the titular astronaut-turned-cyborg secret agent. While the central premise of the show is pure science fiction, amazingly the exotic wingless spacecraft Austin crashes in the title sequence is not the product of some production designer’s fevered imagination. Rather, this sequence uses footage of an actual aircraft – the Northrop M2-F2 – which crashed during a test flight on May 10, 1967. The M2-F2 was one in a long line of experimental aircraft known as lifting bodies, which lack conventional wings and instead use their specially-shaped fuselages to generate lift. As discussed in our previous video $2 Billion Each – a Deep Dive Into the Incredible Engineering That Culminated in the B-2 Stealth Bomber, even in the earliest days of aviation, engineers realized that the conventional aircraft layout of two wings, a fuselage, and an empennage or tail was not necessarily the most effective. The quest for the ultimate flying machine – the aircraft boiled down to its purest, most aerodynamically efficient form – led to the development of the “flying wing”, which has no fuselage, tail surfaces, or other extraneous features. On the opposite end of the spectrum, the development of the lifting body was born of the desire to fly not within earth’s atmosphere, but outside of it, and may hold the key to making regular, affordable, and safe space travel a practical reality. This is the fascinating story of the bizarre aircraft without wings.

Our story begins in early 1944, as Nazi Germany prepared to unleash a new generation of terrifying secret weapons upon the Allies. Known as vergelstungwaffe or “vengeance weapons,” these would allow Germany to strike back at the British Isles as revenge for the round-the-clock bombing raids which had devastated German cities over the past year. The first of these, the Fieseler Fi.103 or V-1, was a small pilotless “flying bomb”, the ancestor of modern cruise missiles. Powered by a simple pulse jet engine and launched by a steam catapult from sites scattered around Northern France, the V-1 was guided by simple autopilot towards its target, whereupon an automatic system would dive the missile into the ground to deliver its one-ton high-explosive warhead. V-1 operations against London began on June 13, 1944, barely two weeks after the D-Day landings in Normandy; 9,521 would be launched, inflicting nearly 23,000 casualties, before the Allied advance across western Europe pushed the launch sites out of range – and for more on this, please check out our previous video On a Wingtip and a Prayer: the Insane Way British Pilots Defeated Germany’s Secret Weapon.

The second V-weapon was even more technologically advanced – and terrifying. Known as the Aggregat 4 or simply the V-2 rocket, this was the world’s first operational ballistic missile. Fuelled by a combination of alcohol and liquid oxygen, the V-2 climbed to an altitude of 88 kilometres – touching the edge of outer space – before descending onto its target at twice the speed of sound. Unlike the V-1, which made a distinctive motorcycle-like sound and was eventually defeated by a combination of accurate anti-aircraft fire and high-speed fighter aircraft, the V-2 approached silently and was all but unstoppable. However, it was also far more complicated, unreliable, and expensive to manufacture, and its combat debut was delayed numerous times. While initial development was carried out at the Peenemünde Army Research Center on the Baltic coast, following Operation Hydra, a massive RAF air rad on August 17, 1943, testing was moved to Blizna in occupied Poland, outside the range of Allied aircraft. However, unexpected problems soon appeared as rocket after rocket began breaking up in mid-flight, causing twisted debris to rain down on the test range. Between November 1943 and March 1944, only four of the 26 successful launches reached the target area in Sarnaki, 200 kilometres to the north. Despite firing dozens more rockets over the following months, engineers were unable to determine the cause of the airbursts, though excessive propellant tank pressure was suspected. In the end, they were forced to implement a stopgap solution: metal sleeves nicknamed “tin trousers” placed over the propellant tanks to strengthen them. Operational V-2 launches finally began six months later. From September 7, 1944 to March 27, 1945, 3,172 V-2s were fired against targets in the UK, France, Belgium, the Netherlands, and Germany, killing some 5,000 people. However, the rockets themselves were largely built by forced labourers from concentration camps, some 10,000 of whom died in the process – making the V-2 the only weapon in history to kill more people in its construction than in combat.

But while the V-2 failed to turn the tide of the Second World War, it would play a significant role in shaping the postwar world order. At the end of the war, the Allied powers – including the United States and Soviet Union – captured large numbers of V-2s as well as the scientists and engineers that helped design them. These men were soon put to work developing the next generation of long-range ballistic missiles, which they combined with the other great technological breakthrough of the war – the atomic bomb – to create the ultimate weapon of mass destruction. Effectively unstoppable and capable of obliterating any city on earth at the push of a button, the intercontinental ballistic missile or ICBM ultimately inspire the policy of Mutually Assured Destruction or MAD whose apocalyptic shadow would loom over the world for more than thirty years.

However, the designers of the first ICBMs faced the same problem which had previously plagued the German V-2 engineers: missiles breaking up as they fell back to earth. The initial solution was to place the warhead in a separate nosecone that would detach from the now-spent rocket fuselage and descend separately to the target. However, as this nosecone plunged through the atmosphere at hypersonic speeds, the air ahead of it would become compressed and heat up to temperatures of up to 2,800 degrees Celsius – hot enough to melt steel. If a means could not be found to dissipate this heat and protect warheads from burning up like meteors on reentry, then the expensive, cutting edge missiles would be all but useless.

Initially, it was assumed that the ideal form factor for atmospheric reentry was long and pointy – the classic science fiction “rocket” shape. After all, such a shape would “slice” cleanly through the air with minimal drag, reducing both compression and fictional heating. However, in the early 1950s a pair of American engineers, Harry J. Allen and Alfred J. Eggers, Jr, made a surprising discovery. Allen and Eggers worked at the Ames Research Centre in California, then run by the National Advisory Committee on Aeronautics or NACA. In 1958, NACA would be reorganized and renamed the National Air and Space Administration – NASA. Using models in a supersonic wind tunnel, Allen and Eggers determined that when long, slender rockets travelled through the air at supersonic speeds, the supersonic shock wave tended to hug the sides of the vehicle, depositing large amounts of heat directly into the airframe. It was this phenomenon which had caused the V-2’s propellant tanks to overheat and burst during reentry. Conversely, if the vehicle were instead made as flat and un-aerodynamic as possible, then the air would not be able to get out of the way fast enough, causing a high-pressure cushion of air to build up ahead of the vehicle. This cushion would not only insulate the vehicle, slowing the transfer of heat to its skin, but also deflect the shockwave away from it, dissipating heat into the surrounding atmosphere. Indeed, Allen and Eggers were able to demonstrate mathematically that the heat load experienced by a reentering vehicle was inversely proportional to its drag coefficient. Based on this rather counterintuitive finding, missile designers soon changed the shape of warhead reentry to high-drag “blunt bodies.”

But this was only part of the solution, for even with the proper shaping a great deal of heat would still get through to the reentry vehicle, threatening to damage or destroy the warhead. At first, this problem was addressed through the use of a heat sink – a large mass of metal like copper or beryllium that could absorb large amounts of thermal energy and prevent the warhead from overheating before it reached its target. This technique was first used in 1959 on the General Electric Mk.2 reentry vehicle for the Convair SM-65 Atlas D, the United States’s first operational ICBM – and to learn how this pioneering weapon inspired the creation of one of the world’s most versatile and beloved household products, please check out our previous video Who Invented WD-40? However, heat sinks were heavy and cumbersome and soon a new type of thermal protection system or TPS was developed: the ablative heat shield. This was composed of multiple layers of phenolic resin applied to the blunt face of the reentry vehicle; when the vehicle reentered the atmosphere, the accumulating heat would cause the resin to char and slough off – that is, to ablate – carrying the heat energy it had absorbed off into the atmosphere. This system was significantly more efficient than heat sinks, requiring relatively thin layers of lightweight resin and allowing much larger warheads to be carried. Ablative heat shields were first deployed on the G.E. Mk. 3 reentry vehicle for the Atlas, and are still used on effectively all military ballistic missiles to this day. As a side note, this design had been predicted by Robert H. Goddard, the father of modern rocketry, who wrote in 1920:

“In the case of meteors, which enter the atmosphere with speeds as high as 30 miles (48 km) per second, the interior of the meteors remains cold, and the erosion is due, to a large extent, to chipping or cracking of the suddenly heated surface. For this reason, if the outer surface of the apparatus were to consist of layers of a very infusible hard substance with layers of a poor heat conductor between, the surface would not be eroded to any considerable extent, especially as the velocity of the apparatus would not be nearly so great as that of the average meteor.”

Allen and Eggers’ discovery was initially classified as a military secret, but eventually published in 1958 – just as the newly-formed NASA was launching Project Mercury, the United States’ first manned space program. The Mercury spacecraft was designed by Maxime Faget, a Belize-born engineer working at NASA’s Langley Research Centre in Hampton, Virginia. Working from the principles uncovered by Allen and Eggers, Faget chose a truncated cone or frustum which would reenter the atmosphere wide end first, forming an ideal blunt body. This blunt end was further covered in a protective heat shield, while the sides of the capsule were covered in tiles made of Rene 41 – a high temperature nickel allow – to protect the cabin from stray heat transfer. The first two manned Mercury flights – Mercury-Redstone 3 on May 5, 1961, and Mercury-Redstone 4 on July 21 – were short suborbital hops conducted at relatively low speeds, so the capsules were fitted with heat sink-style heat shields made of beryllium. However, orbital flights would reenter at much higher speeds, so for all subsequent missions his was changed to a resin ablative heat shield.

Meanwhile, engineers in the Soviet Union discovered the same design principles as the Americans, though their implementation of said principles was often somewhat different. For instance, the Vostok and Voskhod spacecraft that carried Yuri Gagarin and other early cosmonauts into space featured a spherical descent module with ablative heat shield material applied all around, meaning it would protect the occupant no matter the orientation it reentered the atmosphere. However, this design often made for an unpleasant reentry experience, exposing the cosmonaut to rapidly-shifting G forces as the capsule tumbled through the atmosphere. The later Soyuz spacecraft, which is still in use today, switched to a hemispherical “headlamp”- shaped descent module more in line with American designs.

The ablative heat shield concept proved so elegant, reliable, and foolproof that it was retained on NASA’s subsequent Gemini and Apollo capsules and continues to be used on modern spacecraft like the SpaceX Dragon, Boeing Starliner, and Lockheed Martin Orion. Indeed, since the dawn of the space age, not a single manned spacecraft using an ablative heat shield has ever burned up on reentry. But while robust and reliable, ballistic space capsules have several major limitations. Incapable of being steered to a precision landing, they have to be brought down in large areas of open ocean (or, in the case of the Soviet and later Russian space programs, the vast wilderness of eastern Eurasia), require large naval or air fleets to locate and recover them. If, by contrast, a spacecraft could be landed near its launching point, recovery logistics and overall launch costs could be greatly reduced. Indeed, early in the development of the 2-man Gemini capsule, engineers proposed fitting the spacecraft with a steerable, hang-glider-esque parachute called a Rogallo Wing, invented in 1948 by NACA engineer Francis Rogallo. Controlled by cables linked to the astronauts’ regular flight controls, the Rogallo Wing would allow the crew to pilot their spacecraft to a regular landing on a runway, touching down on a set of retractable metal skids. But while extensive gliding tests were performed using mockup capsules, the system proved more difficult to perfect than anticipated, and in the interests of expediency the concept was abandoned in 1964 in favour of a more conventional round parachute and ocean splashdown.

The later Apollo spacecraft that carried American astronauts to the moon incorporated a degree of steering ability into its design. The conical shape of the capsule was carefully designed to produce a certain amount of lift during reentry, allowing it to be “flown” by the crew. This was accomplished by concentrating most of the capsule’s mass off to one side, offset from its aerodynamic centre of pressure. During reentry, the crew used the spacecraft’s reaction control system or RCS thrusters to spin the capsule around its vertical axis, varying the distance between the centre of pressure and centre of gravity and causing the capsule to “fly” at a steeper or shallower angle. In this manner, the crew could adjust their reentry trajectory, allowing them to land closer to the recovery fleet.

But the ultimate dream of spacecraft designers was a winged, fully-steerable vehicle – a “space plane” that could land on a runway like a regular aircraft. Indeed, plans for such a vehicle even predate the start of the Space Race. In the early 1950s, the U.S. Air Force began developing a small 2-man space plane called the Boeing X-20 Dyna-Soar – short for Dynamic Soarer – based on an earlier concept called the Silbervogel or “Silver Bird” developed by German rocket engineer Eugen Sänger – and for more on this astonishing design, please check out our previous video The Nazi Space Shuttle. Launched atop a modified Titan II ballistic missile, the Dyna-Soar would either enter earth orbit or skip along the top of the atmosphere – a manoeuvre called “boost-glide” – to carry out a variety of military missions, including high-altitude reconnaissance and orbital bombing. In 1958, the Air Force also launched a parallel project known as the Aerospaceplane – later the Recoverable Orbital Launch System or ROLS – to develop an even more advanced spaceplane that could fly directly into space without the need for a separate disposable booster – a capability known as Single Stage to Orbit or SSTO. The ROLS would incorporate numerous cutting-edge technologies, including a Liquid Air Collection System that would pull oxygen out of the air and liquefy it for use as rocket fuel. However, the Air Force struggled to find a practical use for Dyna-Soar and the ROLS was quickly found to be infeasible using available technology. Furthermore, manned space initiatives were gradually being taken away from the armed forces and consolidated at NASA. These and other factors led to both projects being cancelled in 1963. Meanwhile, NASA’s overriding goal of landing a man on the moon by President John F. Kennedy’s 1970 deadline led them to eschew advanced spaceplane designs in favour of simpler and more well-understood ballistic space capsules.

But while work on what would eventually become the Space Transport System or Space Shuttle would not begin in earnest until the early 1970s, both NASA and the Air Force conducted extensive studies on spaceplane design throughout the 1960s. One of the major design challenges when it came to spaceplanes – as it was for ballistic capsules – was atmospheric reentry. While a spaceplane would require wings in order to glide to a controlled landing, designers feared these structures would not be strong or heat-resistant enough to withstand the stresses of reentry. Furthermore, wings were heavy and would only be required at the end of a mission; it would thus be inefficient to lug them all the way into orbit, cutting into the spacecraft’s payload capacity. One radical solution first proposed by NASA engineer Robert D. Reed, was to eliminate the wings altogether and shape the spacecraft such that its fuselage generated all the lift. Such craft came to be known as lifting bodies – and it is here at last that we come to the main topic of this video.

The idea of using parts of an aircraft other than the wings to generate lift is nothing new; for example, many of the 1930s aircraft designs of Italian-American engineer Giuseppe Ballanca such as the Bellanca Aircruiser featured fuselages and wing struts shaped like airfoils to increase the vehicle’s aerodynamic efficiency. Later aircraft like the 1960s Short SC.7 Skyvan and McDonnell Douglas F-15 Eagle also use their fuselages to generate significant lift. However, it was not until the 1960s that the technology became available to produce a pure, wingless lifting body aircraft.

In 1962, NASA’s Flight Research Centre – later the Ames-Dryden Flight Research Centre and today the Armstrong Flight Research Centre – approved the construction of a test vehicle to investigate the flight characteristics of lifting body aircraft. Known as the M2-F1 – “M” for “manned” and “F” for “flight” – the vehicle had a tubular steel frame covered in a mahogany shell and was hand-built by engineers and craftsmen from NASA and the Briegleb Glider Company. Much of the woodworking was performed by master craftsmen Gus Briegleb and Ernie Lowder, the latter of whom had previously worked on billionaire Howard Hughes’s gigantic H-4 Hercules all-wood flying boat – AKA the “Spruce Goose.” All told, construction cost a mere $30,000 – largely taken from the research centre’s building maintenance budget. Due to the low-rent nature of the venture, the assembly workshop at El Mirage Airport was nicknamed the “Wright Bicycle Shop” – and to learn more about the amazing story of the real Wright Brothers, please check out our previous video How Did the Wright Brothers Win the Race Into the Air?

Completed in 1963, the M2-F1 looked like something straight out of science fiction – and like nothing even remotely capable of flight. Measuring only 6 metres long and 4 metres wide, it had a rounded, triangular body with a curved belly and flat top, earning it the nickname of “flying bathtub”. Two small vertical fins with rudders on either side of the fuselage provided lateral control, while a set of horizontal elevons controlled the aircraft in pitch and roll. These were actuated manually using conventional pushrod controls, while the fixed landing gear was scavenged from a Cessna 150 light aircraft.

Flight tests took place on the wide expanse of Muroc Dry Lake – today Rogers Dry Lake – in California’s Mojave Desert – home to both the NASA Armstrong Flight Centre and Edwards Air Force Base. At first, the M2-F1was towed along the lakebed behind a 1963 Pontiac Catalina convertible, with test pilot Milt Thompson making the first short hops on April 5, 1963. Unfortunately, the strange aircraft bounced uncontrollably on its landing gear, forcing Thompson to keep the nose down for fear of flipping over. Subsequent tests encountered the same problem, which was eventually traced to unwanted rudder movements. The flight controls were duly modified, and the problem disappeared. However, a new problem had appeared: the tow car was not powerful enough to lift the M2-F1 off the ground. The vehicle was duly hot-rodded to increase its power and fitted with a roll bar and a rearward-facing seat to allow the M2-F1 to be observed in flight. Soon, tow speeds reached 180 kilometres per hour, allowing Thompson to reach altitudes of around 6 metres before cutting the tow line and gliding freely for about 20 seconds. In total, Thompson performed some 400 auto tow flights, gathering valuable data on lifting body aerodynamics and handling characteristics.

On August 16, 1963, Thompson piloted the M2-F1 on its first high-altitude flight, towed behind a Douglas DC-3 transport aircraft. For these tests the “flying bathtub” was fitted with an ejection seat as well as a set of small booster rockets to allow the pilot to increase airspeed extend his landing by a few seconds if needed. One of the major questions which aircraft like the M2-F1 were designed to answer was whether a reentering spaceplane could make a safe landing completely unpowered or whether some kind of auxiliary propulsion – either a rocket or jet engine – was needed. On a typical test flight, the M2-F1 was towed to an altitude of 3,700 metres and released, whereupon it took around two minutes to spiral to the ground. Naturally inefficient as a glider, the aircraft had a terrifying sink rate 66 kilometres per hour and reached maximum speeds of 190 kilometres per hour. In total, the M2-F1 made 77 flights between August 1963 and August 1966, being flown by 10 different test pilots including legends Chuck Yeager and Bill Dana and future NASA astronauts Fred Haise and Joe Engle. Despite a handful of minor mishaps, the aircraft performed well, paving the way for further lifting body research. The pioneering M2-F1 was transferred to the collection of the National Air & Space Museum in Washington, D.C., but in 2015 was loaned out to the Air Force Flight Test Museum at Edwards Air Force Base where she remains on display to this day.

In 1963, as the M2-F1 was nearing completion, NASA contracted the Northrop Corporation – ironically known for their all-wing aircraft designs – to create a more capable advanced lifting body research vehicle, designated the M2-F2. Completed in 1966, the M2-F2, the aircraft was 1 metre narrower than its predecessor but weighed four times as much, being built of aluminium instead of wood. It also featured retractable landing gear for reduced drag and the provision for installing various types of rocket engines. The M2-F2 made its first unmanned captive flight on March 23, 1966, the aircraft being mounted to a pylon under the right wing of a modified Boeing B-52 Stratofortress bomber. On July 12, it made its first unpowered glide test with Milt Thompson once again at the controls, the aircraft being released from the mothership at an altitude of 12,000 metres and reaching a top speed of 720 kilometres per hour. A further fourteen glide tests were performed without incident. But on the sixteenth, conducted on May 10, 1967, disaster struck. As the M2-F2 approached the runway, test pilot Bruce Peterson experienced a phenomenon known as dutch roll – an uncommanded oscillation in roll and yaw. While Peterson managed to get the aircraft back under control, he became distracted by a nearby helicopter and drifted away from the runway. Finding it difficult to determine his height above the lake bed, Peterson fired his landing rockets to try and gain speed, but it was too late; the M2-F2 slammed into the ground before the landing gear could fully deploy and rolled over six times, coming to a rest upside-down. Miraculously, Peterson survived the impact and eventually made a full recovery, but unfortunately lost his right eye to an infection. It is footage of this dramatic crash which was later used in the opening title sequence of The Six Million Dollar Man.

The instability that triggered the crash was ruled to be pilot induced oscillation or PIO, caused by a lack of adequate lateral control. The M2-F2 was thus rebuilt as the M2-F3, which featured a ventral fin for greater directional stability. The M2-F3 was first flown on June 2, 1970 by test pilot Bill Dana. Two more unpowered glides followed before the aircraft was fitted with a 36 kilonewton thrust Reaction Motors XLR-11 rocket engine. Fuelled by alcohol and liquid oxygen, the engine featured four combustion chambers that could be individually lit to vary the overall thrust. The first powered flight took place November 25, 1970, with Bill Dana once again at the controls. Over the next two years Dana, along with test pilots John Manke, Cecil Powell, and Jerauld Gentry, made 24 powered flights, reaching a maximum altitude of 21,800 metres and a maximum speed of Mach 1.6. It is worth noting here the enormous advancements made in supersonic aerodynamics since Chuck Yeager first broke the sound barrier in level flight on October 14, 1947. His aircraft, the Bell X-1, used the same engine as the M2-F3, yet despite looking far more aerodynamic than NASA’s “flying bathtub”, struggled to exceed Mach 1. In the course of the M2-F3’s research career, test pilots discovered that lifting bodies are inherently unstable and difficult to fly using traditional direct flight controls. Thus, on later flights the aircraft was fitted with a prototype stability augmentation or “fly by wire” system, which used computers to analyze the pilot’s control inputs and translate them into the rapid control surface movements needed to keep the aircraft flying stably. The aircraft was also fitted with an experimental side mounted control column or “side stick”; both technologies are widely used on modern aircraft. Following its retirement in 1972, the M2-F2 was also donated to the National Air & Space Museum and currently hangs in the National Mall building’s Milestones of Flight gallery.

In parallel with the M2-F3, Northrop also built and tested another lifting body demonstrator known as the HL-10 – “HL” standing for Horizontal Lander. Though similar in shape and dimensions to the H2-L1, the HL-10 had an inverted fuselage shape, with a flat bottom and curved top into which the cockpit canopy was faired. The aircraft cost $1.8 million to build, and to save money many parts were scavenged from other aircraft, such as landing gear from a Northrop T-38 Talon supersonic trainer and an ejection seat from a Convair F-106 Delta Dart interceptor.

The HL-10 was completed in January 1966 and made its first unpowered flight on December 22, piloted by Bruce Peterson – who the following year would crash spectacularly in the H2-F2. Shortly thereafter, the aircraft was fitted with an XLR-11 rocket engine, though the next 11 drops were flown unpowered to evaluate the aircraft’s handling characteristics. The first powered flight took place on October 23, 1968 with Jerauld Gentry at the controls, though the engine suffered a malfunction and Gentry was forced to land only three minutes after launch. On the next flight, on November 13, 1968, John Manke tried three times unsuccessfully to light the engine, while on the flight after that Gentry finally succeeded in making a full powered flight. The aircraft made a further 12 successful powered flights, reaching a maximum altitude of 27,440 metres and a maximum speed of Mach 1.86. On later flights, pilots made high speed approaches from high altitudes to study proposed landing profiles for space planes reentering the atmosphere – flights which involved landing at speeds of up to 300 kilometres per hour. As with the H2-H2, three Bell 500 pound thrust hydrogen peroxide booster rockets were fitted to provide extra thrust during landing if needed and determine whether such boosting would be needed on future space planes. The data collected during these flights would later prove invaluable to the design of the Space Shuttle. The HL-10 is currently on display at Air Force Flight Test Museum at Edwards Air Force Base, along with the M2-H1.

But Northrop was not the only name in the lifting body game. In 1963, the United States Air Force contracted the Martin Marietta Corporation to design a number of lifting body demonstrators for spaceplane reentry research. The first of these, designated the SV-5D and later the X-23A PRIME for Precision Reentry Including Maneuvering reEntry (don’t you love a good forced acronym?), were small 2 metre long by 1.2 metre wide unmanned vehicles designed to be launched into space atop a Convair SM-65 Atlas ballistic missile. The vehicles were constructed from titanium, stainless steel, aluminium, and beryllium, coated in ablative heat shield material, and fitted with a nitrogen gas control system to allow them to perform maneuvers while reentering the atmosphere. Once the vehicles reached an altitude of 30 kilometres, they deployed a recovery parachute and were “snatched” in midair using a modified Lockheed JC-130B Hercules aircraft in a similar manner to the film canisters from Corona reconnaissance satellites – and for more on another batshit crazy Cold War system used to snatch people into the air, please check out our previous video The Real Story of Capturing an Ice Fortress with a Badass James Bond Film Device. Three X-23A missions were launched from Vandenberg Air Force Base, California on December 2, 1966, March 5, 1967, and April 19, 1967, but various technical failures caused the first two vehicles to sink into the Pacific Ocean before they could be recovered. However, the third mission was a complete success and the recovered X-23A is now on display at the Museum of the United States Air Force in Dayton, Ohio.

Meanwhile, Martin built a piloted lifting body demonstrator called the SV-5P – later renamed the X-24A. Similar in design to the Northrop HL-10 though slightly larger, the X-24A had a flat bottom and curved top surface, was powered by an XLR-11 rocket engine, and fitted with two Bell solid propellant rocket motors for landing. Like the previous Northrop lifting body aircraft, it was also launched from a modified B-52 bomber. The X-24A made its first unpowered gliding flight on April 17, 1969 and its first powered flight on March 19, 1970, piloted both times by Jerauld Gentry. In total, the aircraft flew 29 times, reaching a maximum altitude of 21,800 metres and a maximum speed of Mach 1.52. In the early 1970s, the aircraft was rebuilt into a radically different flat wedge shape dubbed the “flying flatiron”, which first flew unpowered on August 1, 1973 with John Manke at the controls. The aircraft was flown 36 times before being retired on November 26, 1975, reaching a maximum speed of Mach 1.76 and successfully demonstrating that a reentering spaceplane could safely make a precision gliding landing without any additional thrust being required.

In the mid-1970s, various proposals were floated for an X-24C variant that would use supersonic combustion ramjet or scramjet engines to reach hypersonic speeds of up to Mach 8, but nothing came of these plans. Martin also built a pair of jet-powered versions of the X-24A called the SV-57 for pilot training purposes; however, they were unable to convince any test pilots to fly the aircraft, and they were never used. Also unrealized were plans to turn the Northrop HL-10 into the world’s first operational space plane by fitting it with a heat shield and reaction control system. Taking advantage of the large amounts of hardware left over from the Apollo moon landing programme, the proposed mission profile called for the HL-10 to be launched into earth orbit by a giant Saturn V rocket, mounted in the space usually reserved for the Lunar Module or LM. The crew would ride separately aboard a Apollo Command-Service Module or CSM as per usual. Once in orbit, a robotic arm would extract the spaceplane from its adaptor and bring it alongside the CSM, allowing the pilot to spacewalk over, power up the vehicle, and fly it back down to earth. However, the head of the NASA Flight Research Centre saw the scheme as an inefficient and expensive use of resources, and along with nearly all proposed post-Apollo missions, it was never flown.

And while the M2-F2, HL-10 and X-24 programmes gathered valuable data on lifting body aerodynamics, fly-by-wire control systems, and unpowered reentry profiles, in the end NASA opted not to use a lifting body design for the Space Transport System AKA the Space Shuttle. The main issue was with propellant storage; for the shuttle, NASA selected a combination of liquid oxygen and hydrogen, which must be stored in cylindrical pressure vessels. Such vessels are difficult to fit into the complexly-curved shape of a lifting body aircraft without creating a great deal of wasted space. Furthermore, lifting bodies have very small glide ratios descend at extremely high speeds, giving them a very restricted landing envelope and requiring very long runways. However, NASA wanted the shuttle to be able to land at a variety of alternate runways in case of poor weather at the primary landing site. As a result, the Space Shuttle was designed with a more conventional delta-winged configuration. This proved a fateful decision, as NASA was to learn during the STS-107 mission of the space shuttle Columbia. When the shuttle launched into orbit on January 16, 2003, a piece of insulating foam broke off the external propellant tank, striking the left wing and damaging the reinforced carbon-carbon composite leading edge. When the shuttle reentered the atmosphere two weeks later on February 1, hot plasma entered the breach and caused the shuttle to disintegrate in midair, killing all seven astronauts aboard. Had the shuttle used a lifting body design, such vulnerable edges would have been minimized and the vehicle may have survived reentry.

On the other side of the Iron Curtain, the Soviet Union was also pursuing its own spaceplane project, even more advanced and ambitious than American efforts. In 1960, the OKB-155 design bureau under famous Soviet aircraft designer Artem Mikoyan – the “M” in MiG – began working on a concept known as the Spiral OS, composed of three main components: a reusable GSR delta-winged, ramjet-powered supersonic launch aircraft; an RB two-stage rocket booster; and an OS orbiter. The GSR would boost the OS-RB combination to a speed of Mach 6 at an altitude of 30 kilometres, whereupon the RB would ignite and insert the OS into an initial 130 kilometre orbit. As this orbit could only be sustained for a short time before atmospheric drag caused it to decay, the OS would then fire its own engines to gain altitude. Meanwhile, the GSR mothership would return to base, ready to be used for another launch.

The design of the OS spaceplane itself was highly innovative, featuring variable dihedral wings. During reentry, these would be folded vertically to place them in the “shadow” of the heat shield and protect them from damage. During this phase, the specially-shaped fuselage would generate the required lift in the same manner as the American lifting-body proposals. Once the vehicle reached a safe speed, the wings would fold down horizontally, allowing the aircraft to land on a conventional runway. To increase landing range and provide capability for emergency go-around, a small turbojet engine was also fitted. Interestingly, the American Space Shuttle was originally supposed to feature such engines, but these were ultimately deleted to save weight. Perhaps the most distinctive feature of the Spiral OS was its turned-up nose, designed to reduce heating of the rear fuselage during reentry. This earned the vehicle the nickname Lapot – a traditional blunt-ended peasant’s shoe made of woven tree bark. To avoid cutting holes in the heat shield, the landing gear – comprising four metal skids – was stored in the upper, unshielded section of the spacecraft and folded down just before landing. Finally, in case of an emergency, the pilot could detach the entire cockpit from the spaceplane, which served as a miniature reentry capsule complete with heat shield.

These design features, along with the spacecraft’s unique launch profile, would have given the Spiral OS numerous advantages over the later NASA space shuttle. For instance, the folding wings, landing engine, unbroken heat shield, and pilot escape capsule would have made the spacecraft far safer and robust than the STS orbiter, likely allowing the crew to survive a Columbia-style reentry incident. Furthermore, the reusable aircraft launch system would have allowed the Spiral to reach any orbital inclination, carry two or three times the payload of a conventional launch vehicle of the same mass, and reduced the cost per launch by up to threefold.

The test project was to be divided into three phases. The first would involve unmanned models launched into space atop rockets in the same manner as the American X-23 PRIME. The second phase would involve the construction of a manned, jet-powered vehicle dropped from a modified Tupolev Tu-95 “Bear” strategic bomber to test subsonic handling. This vehicle would later be fitted with rocket engines, allowing it to reach speeds of up to Mach 8. Finally, phase 3 would involve launching a manned, sub-scale spaceplane into orbit using a conventional Soyuz launch vehicle to prove out the vehicle’s systems and reentry capability. Interestingly, Soviet engineers initially had difficulty combining the Soyuz rocket with the Spiral, whose highly-asymmetric weight distribution tended to unbalance the launch vehicle. It was thus suggested that the spacecraft be towed into orbit behind the rocket. As the spacecraft was already designed to withstand the heat of atmospheric reentry, it could easily survive the rocket’s exhaust, meaning this idea was not as crazy as it sounds. Ultimately, however, engineers figured out how to fit the spaceplane atop the rocket.

But while official approval to build the Spiral OS was given in 1966 and a group of cosmonaut test pilots chosen the year before, enthusiasm for the project was hard to maintain among the upper echelons of the Soviet government, and following the Apollo 11 moon landing in July 1969, the project was cancelled before much hardware had been completed.

However, in 1974 the Spiral project was suddenly restarted in response to the American Space Shuttle program. Amusingly, the Space Shuttle greatly concerned the Soviets, who believed it could snatch their satellites out of orbit and return them to the United States for study. Spoiler alert: it could not. To collect subsonic atmospheric handling data for the new project, now designated the Experimental Passenger Orbital Aircraft or EPOS, the Mikoyan design bureau constructed a small, jet-powered version of the “Lapot” design known as the MiG-105. The aircraft made its first powered flight on October 11, 1976, and was first dropped from a Tu-95 mothership on November 27, 1977. In total, the MiG-105 made eight test flights with test pilot A.G. Festovets at the controls, until a hard landing in September 1978 resulted in the aircraft being written off and retired. Nonetheless, the test programme demonstrated the fundamental soundness of the design – including the variable-dihedral wings. Meanwhile, a series of small unmanned models were built to test heat shield materials and reentry manoeuvring. Known as Bespilotnyi Orbital’nyi Raketoplan or “Unpiloted Orbital Rocketplanes” – BOR for short – the models were launched into space from the Kapustin Yar complex in Astrakhan Oblast, Russia, atop Kosmos-3M rockets before reentering the atmosphere and splashing down in the Indian Ocean, where they were recovered by Soviet Navy Vessels. Six different BOR models were built, with fifteen confirmed launches being conducted between 1969 and 1988.

By this time, however, the Spiral concept had been abandoned in favour of the Buran spacecraft, which externally appeared very similar to the NASA Space Shuttle. But once again the Soviet design was in many ways superior to its American counterpart. For instance, while the Space Shuttle carried its own hydrogen-oxygen rocket engines, the propellant being supplied from a large external tank, Buran was strapped to the side of standalone liquid-fuelled Energia super-heavy booster, eliminating the weight of onboard engines and allowing the orbiter to carry a larger payload. This configuration also eliminated the need for the dangerous and un-extinguishable solid rocket boosters or SRBs which triggered the Space Shuttle Challenger disaster on January 28, 1986.

Buran made its first – and only – unmanned flight on November 15, 1988, lifting off from Baikonur Cosmodrome in Kazakhstan, completing two orbits of the earth, and landing automatically on the runway back at Baikonur. A second unmanned flight was planned for sometime in 1993, but the breakup of the Soviet Union in 1991 resulted in the project’s cancellation. The prototype was placed in storage, only to be destroyed in 2002 when its hangar collapsed.

But while the 1960s dream of sleek, lifting body spaceplanes never came to fruition, the concept may be poised to making something of a comeback, with several proposed spacecraft concepts in recent years using elements of the lifting body design. These include the RSC Energia Kliper, the Orbital Sciences Corporation Prometheus, the Sierra Nevada Corporation Dream Chaser Space System, the ESA Hermes, the NASA HL-20 Personnel Launch System, the NASA/Scaled Composites X-38 Crew Return Vehicle, and the Lockheed Martin Venturestar. The latter concept is particularly ambitious, designed to combine single-stage-to-orbit or SSTO and horizontal landing capability – the holy grail of reusable spacecraft design. Due to budget cuts, technical failures, and other factors, nearly all of these projects were eventually cancelled, with only the Dream Chaser currently in active development. But the trials and tribulations of these modern projects are an enormous subject for a separate video; for now, while the future of the lifting body spacecraft seems uncertain, at least the experiments of the 1960s, 70s, 80s have shown the concept to be perfectly feasible. In other words: we can built it – we have the technology!