The Rise and Fall of Spaceplanes: A History of Ambitious Concepts
Spaceplanes have long captured the imagination with their sleek, futuristic designs and the promise of revolutionizing space travel. Unlike traditional rockets, these vehicles are designed to be reusable, offering multiple flights and significantly reducing launch costs. Some can take off and land on conventional runways, while others are launched from rockets or “motherships,” making them more efficient and environmentally friendly. Despite their potential, many spaceplane projects have never moved beyond the drawing board. Let’s explore some of the most intriguing and ambitious spaceplane concepts that never quite took off.
10: HOTOL
The UK’s interest in space travel began before World War II, led by the British Interplanetary Society, which included notable figures like Arthur C. Clarke. After the war, Britain studied captured German V-2 rockets and proposed crewed suborbital flights, such as Megaroc. In 1952, official programs focused on military and scientific research, with Skylark rockets launching from Woomera starting in 1957.
In 1971, the Prospero satellite was successfully launched by the Black Arrow rocket, but the program was soon canceled, ending Britain’s independent spaceflight efforts. British Aerospace, formed in 1977, aimed to revive the country’s space ambitions.
In collaboration with Rolls-Royce, British Aerospace proposed HOTOL (Horizontal Take-Off and Landing). Concept studies began in the early 1980s, with the formal project starting in 1986. The goal was to create a single-stage-to-orbit spaceplane powered by the innovative RB545 “Swallow” engine. This hybrid air-breathing rocket engine promised seamless, single-stage, reusable spaceflight. However, the project was canceled in the late 1980s due to funding issues and technical challenges.
9: MiG-105
The Soviet MiG-105 was a spaceplane project with roles including the destruction of NATO satellites. It was envisioned to be launched from the back of a Mach 6 Tupolev carrier aircraft. After separation at high altitude, its own detachable rocket booster would propel it into a sub-orbital altitude.
The MiG-105 emerged from the Soviet Spiral programme, aiming to create a small orbital spaceplane that could return to Earth like a glider. Its compact, wedge-shaped body earned it the nickname “Лапоть” (Lapot) or “Little Shoe.”
The MiG-105 was used to test landing techniques and low-speed flight characteristics. It conducted eight subsonic flight tests between 1976 and 1978. Although the project was later canceled, its unmanned sister craft, the БОР (BOR), successfully conducted several space missions. One surviving example is now housed at the Monino Museum in Moscow.
8: Boeing X-20 Dyna-Soar
The X-20 Dyna-Soar was a United States Air Force spaceplane project developed during the late 1950s and early 1960s. Designed for reconnaissance, bombing, and space research missions, it was a reusable, rocket-powered craft combining the manoeuvrability of an aircraft with the capabilities of an orbital vehicle.
The X-20 was to be launched atop a modified Titan IIIC rocket, separating once sufficient altitude and velocity were achieved. After detaching from its booster, it would continue into orbit under its own momentum. This launch method allowed the vehicle to function as both a spacecraft and a glider upon re-entry.
The X-20 was canceled in 1963 as US political priorities shifted toward NASA’s Apollo programme. Though never completed, the X-20 profoundly shaped later space efforts. Its research informed the Space Shuttle’s heat shielding, reusable lifting-body design, and pilot-controlled re-entry systems. Elements of its engineering resurfaced decades later in the X-37B.
7: Lockheed Martin X-33 / VentureStar
The X-33 was a subscale technology demonstrator for Lockheed Martin’s proposed VentureStar, a fully reusable, single-stage-to-orbit spacecraft intended to drastically reduce launch costs. It featured cutting-edge composite cryogenic hydrogen fuel tanks and a lifting-body shape (no wings).
The X-33 used linear aerospike engines, which worked like a normal rocket but without a bell-shaped nozzle. Instead, exhaust flowed along a wedge-shaped spike. Air pressure outside the rocket helped shape and squeeze the exhaust, keeping thrust efficient at all altitudes.
The project was canceled due to technical and financial setbacks, primarily the failure of the composite hydrogen fuel tank, which cracked during testing. The tank’s failure caused significant delays and cost overruns, and NASA concluded that Single-Stage-to-Orbit technology wasn’t yet feasible with existing materials and propulsion systems.
6: Hermes
Hermes was a European reusable spacecraft developed under the European Space Agency during the 1980s and early 1990s. Conceived as Europe’s answer to the American Space Shuttle, it was intended to transport three astronauts and small payloads to low Earth orbit.
The design combined spacecraft and aircraft principles, aiming for controlled, horizontal runway landings after re-entry. Hermes was to be launched atop the Ariane 5 rocket, simplifying the design and reducing weight.
The project was canceled due to escalating costs, delays, technical difficulties, and shifting political priorities. After the Cold War, reduced justification for high-prestige manned missions also contributed to the European Space Agency’s termination of the project in 1993.
5: HL-20 Personnel Launch System
The HL-20 Personnel Launch System, developed at Langley Research Center during the late 1980s, was a proposed lifting-body spaceplane designed for routine crew transport. Inspired by the Soviet BOR-4, it could carry up to 8 passengers into orbit while promising safer and more efficient recovery than capsule designs.
The HL-20 would launch atop expendable rockets such as Titan III or Atlas, then glide to Earth for a horizontal landing. Its compact, aerodynamic form offered enhanced stability during re-entry, significantly reducing stress and thermal load.
Built from lightweight materials, the HL-20 required less refurbishment than the Space Shuttle, reducing operational costs. It was intended to be launched from existing facilities, enabling flexible scheduling and rapid deployment for orbital servicing or crew rotation at future space stations.
4: Sänger II
Arguably the coolest-looking spaceplane ever considered, the Sänger II was a proposed West German spaceplane concept by Messerschmitt-Bölkow-Blohm from the 1980s. The original Sänger spaceplane, conceived by Eugen Sänger in the 1940s, was an exotic German concept for a rocket-powered, suborbital bomber called the “Silbervogel.”
Decades later, its principles inspired the Sänger II, a two-stage spaceplane concept for orbital missions. The Sänger II was designed as a two-stage-to-orbit system intended to carry payloads or passengers into low Earth orbit.
Its launch method involved a horizontal take-off from a conventional runway, using jet engines to reach high subsonic speed before switching to rocket propulsion. This air-breathing start was a key feature, reducing fuel consumption compared with vertical launches.
3: Rockwell X-30
Having successfully created the Space Shuttle, Rockwell was well placed to develop another spaceplane. Their X-30 was a visionary concept developed under the National Aero-Space Plane (NASP) programme during the 1980s. It aimed to create a single-stage-to-orbit spaceplane capable of horizontal take-off and landing.
Powered by scramjet engines, the X-30 aimed to transition smoothly from atmospheric flight to orbital insertion. Its propulsion system would have drawn oxygen from the atmosphere during ascent, reducing the need for heavy onboard oxidizers and improving fuel efficiency.
Although the project was eventually canceled due to technical and financial challenges, the X-30 programme contributed valuable research to hypersonic flight, propulsion, and materials science. Its ambitious goals continue to influence modern spaceplane development efforts worldwide.
2: Buran
The Buran was the Soviet Union’s response to NASA’s Space Shuttle, developed by NPO Molniya, launched atop the Energia rocket built by RSC Energia. Designed as a reusable spacecraft, it represented the pinnacle of Soviet aerospace engineering.
In contrast to the Space Shuttle, it didn’t use an internal propulsion system to take it into orbit. It relied on the Energia. The Energia launch vehicle was a powerful, fully expendable heavy-lift rocket capable of placing over 100,000 kg into low Earth orbit.
Once in orbit, the Buran relied on its own small orbital manoeuvring engines and reaction control thrusters. These were powered by hypergolic propellants, providing precise control for orbital adjustments, docking operations, and atmospheric re-entry alignment.
1: Skylon
Skylon originated from Britain’s 1980s HOTOL programme. After HOTOL’s cancellation, its chief designer, Alan Bond, founded Reaction Engines Limited in 1989 to continue development. Early work focused on the revolutionary SABRE air-breathing rocket engine.
The vehicle’s launch method was envisioned to be similar to that of a traditional aircraft, rolling down a runway before ascending. Its design would have allowed it to accelerate through the atmosphere efficiently, relying on air-breathing propulsion at lower altitudes.
At the heart of Skylon was the SABRE engine, a hybrid air-breathing rocket system that would have intaken atmospheric oxygen during the early ascent, mixing it with onboard hydrogen fuel. Once above the atmosphere, it would have switched to an internal oxidizer, functioning as a conventional rocket.
Thermal management was critical to the design, with precoolers intended to chill incoming air and prevent engine overheating at high speeds. Lightweight composite materials and advanced heat shielding were expected to allow sustained hypersonic flight. Skylon’s concept promised rapid turnaround, reusability, and reduced environmental impact. However, progress remained limited to engine technology demonstrations. Reaction Engines successfully tested SABRE’s precooler technology but never built a full engine or vehicle. In October 2024, the company entered administration, ending active development. With Reaction Engines now defunct, Skylon remains an ambitious but unrealized vision of Britain’s return to space.
