Spaceplanes


Spaceplanes

Not all space missions follow a ballistic flight path, but some use their body to generate lift. The most famous one is the US Space Shuttle, but there have been many more. This page shows a collection of space planes that are, have been or will be operational. A list of experimental space planes can be found here.


Space Shuttle

Operator: USA

Mission: Reusable crewed space plane

First flight: 1981-2011

Status: Retrired 


Afther the design of the Apollo programme was completed, NASA planned for their new vehicle. This vehicle should, unlike the Apollo command module, be reusable. In 1981, after approximately 15 years of designing, building and testing, STS-1 (Space transportation system) Space Shuttle Columbia lifted off the launch pad. This was the beginning of a 30-year-long era of Space Shuttle flights.

The space shuttle vehicle consisted of four main parts: the orbiter, the external tank and two boosters. The boosters would provide the initial thrust for the tank and orbiter to be able to reach orbit. The external tank, which contained 543000l of LOX and 1080000l of liquid hydrogen, had no engine and would be discarded once all the propellants were used [200]. The space shuttle orbiter could lift 29000kg into orbit [204].

The reusable orbiter had three main Space Shuttle Main Engines besides a multitude of smaller manoeuvring engines. The orbiter had a 24m span delta wing, was 37m long, 17m high and had an empty mass of 78000kg[200,206]. The thermal protection system on the space shuttle consisted of, among others, the reinforced carbon-carbon elements at high-temperature locations, such as the nose-tip and the leading edges of the delta wing [200]. The completed underside of the orbiter and part of the side was covered in High-Temperature and Low-Temperature Reusable Surface Insulation. These were in total, 25000-30000 silica tiles, essentially very pure quartz sand,  that protected the space shuttle during the re-entry. 

Space shuttle before launch
Space shuttle landing with parachute deployed

After re-entry, the space shuttle would autonomously guide itself to one of two possible Space shuttle runways. These were at Edwards Airforce Base and Kennedy Space Center. From the 1990s onwards, after touching down a 12 m reefed braking parachute would be deployed to aid in the deceleration[205].

Six orbiters were made: one test vehicle (Enterprise) and five operational orbiters (Columbia, Challenger, Discovery, Endeavour, Atlantis). All six were named after exploratory vessels [203]. Over its long career, the Space Shuttle deployed the Hubble space telescope and performed its servicing missions. It launched the Galileo orbiter to Jupiter, and Space shuttles also aided in building the International Space Station. The five Space Shuttles performed in total 135 missions and spent a total of 1320 days in orbit. On the 21st of July 2011, after 30 years in service, the space shuttle program ended when Space Shuttle Atlantis completed STS-135 by touching down at the Kennedy Space Center [201,202].


Buran

Operator: Soviet Union

Mission: Reusable crewed space plane

First flight: 1988

Status: Retrired/cancelled 


With the US having announced the Space Shuttle, the USSR, although initially slow to respond, could not remain behind, and in 1976, under the leadership of the Ministry of Defence and NPO Energiya, the Development of the Soviet spaceplane began. Although there was already some minor spaceplane research within the Soviet Union, for what would become the Buran, major "inspiration" was taken from the US space shuttle to reduce the development time [209].


Putting the two concepts of the space shuttle and the buran side-to-side, they look almost identical. However, there are some major and minor differences. The most obvious one is that the Buran would use four liquid boosters instead of two solid boosters to get into orbit. These boosters were also originally designed to be reusable. However, this was soon discarded because this would cause a loss of payload to orbit. The main propellant tank would almost be a copy of the space shuttle's external tank with 552000 l of LOX and 1523000 l of LH2. The Buran would, however, have the main engines on the tank and not on the orbiter [209].

The orbiter was again very similar to the space shuttle orbiter, without the previously mentioned missing main engines. It had a double-delta wing, a wingspan of 24m, a length of 36m and a diameter of 5.5m. It could carry a 30t payload into orbit and had a mass at lift-off of 105t [209,210]. The thermal protection system used 38800 silica tiles, divided into high- and low-insulation types. The nose tip and the leading edge of the wings were made out of reinforced carbon-carbon. It would be capable of autonomously flying and landing. Finally, immediately at touchdown, 3x cross-type parachutes would deployed to reduce the required landing length [209].

Buran during landing

Buran during landing

The final big difference between the Buran and the Space Shuttle is its operational history. Where the Space Shuttle had a total of 135 orbital missions, the Buran only had 1. On the 15th of November 1988, the first and last Buran flight took place. It lasted only a little under 3.5 hours. Plans were made for more flights, and more Buran orbiters were already in production. However, after the collapse of the Soviet Union, all the funding for the Buran disappeared [209].

Buran in launch position

Buran in launch position

Space Rider

Operator: ESA

Mission: Reusable payload delivery vehicle

First flight: Unflown 

Status: In development


Space Rider, Space Reusable Integrated Demonstrator for Europe Return, is a small spaceplane developed by Italy in collaboration with ESA. Space Rider will launch on the Italian built Arianespace operated Vega-C launcher. The objective is to bring a payload of 800 kg to orbit and back. The vehicle is designed for at least six flights. 


Space Rider in orbit showing the capsule and the service module

Atmospheric Entry

The space rider capsule is a lifting body type spacecraft. That means that much like the space shuttle, the capsule generates lift. A lift generating capsule is more complex than a ballistic entry capsule, but the maximum deceleration and thermal loads are lower. Space Rider's ability to perform a gliding entry was tested in the ESA IXV mission, which flew a suborbital trajectory using a Vega launcher in 2015. From the render, one can see that the spacecraft does not have any wings; this is due to the lifting body design, which means that the spacecraft body itself generates sufficient lift to perform a gliding entry. This is unlike the US Space Shuttle or Russian Buran. This also means that the capsule cannot land by itself and requires a parachute system for a safe landing. 


Parachute system

Even though the Space Rider has a lift generating body, it cannot generate sufficient lift for a safe landing. Therefore it requires a parachute system for the final landing. The space rider parachute system consists of two drogue parachutes and a 70 m2parafoil main parachute. The parafoil can be seen below during an X38 test flight. Parafoils are lift-generating parachutes. This means that they work much like the wing of an aircraft. 


Dream Chaser

Operator: Sierra Space Corporation

Mission: Cargo flights to the LEO, possible human flights

First flight: Q7 2024

Status: In development


Since the space shuttle was completed, there was always this need for a second smaller space plane to complement its operation. This was planned to be the HL-20, but this project was never finalized into an operational vehicle.

Sierra Nevada Corporation using the HL-20 design (internal link), which originates from the BOR space planes (internal link), updated the design using the modern state-of-the-art and created the Dream Chaser. The dream chaser, just like the HL-20 and the BOR before it, is a small lifting body space plane. The HL-20 design was updated to use modern composite materials, a propulsion system and a non-toxic RCS system. Finally, the fins of the HL-20 are updated to have an airfoil cross-section, as recommended at the end of the HL-20 project [184].


The propulsion system of the Dream Chaser is a hybrid propulsion system using HTPB and Nitrous, which is restartable and throttleable. The RCS system uses 800 lbs of ethanol and nitrous as a non-toxic alternative to the RCS system of the HL-20 [184].

The Dream Chaser was initially designed to be launched on the Atlas V. However, as the Atlas is being replaced, it will use ULA's new Vulcan launcher to get into orbit. Its primary purpose is to ferry a crew of 7 or 12000 lbs of cargo to the ISS [184,185]. Because of the lifting-body design, the descent is more "gentle" than a standard capsule return. Due to the L/D ratio of 1.4 during the hypersonic phase and an L/D of 4 during landing, the maximum deceleration of the Dream Chaser is limited to 1.5g [184]. Standard operations are to be run from Kennedy Space Centre, with it landing on the runways used for the space shuttle. However, in an emergency, it can also use regular commercial runways as long as they are at least 7000ft [184].

The first test flight of the Dream Chaser is planned for Q1 2024, which is a demonstration mission to fly to the ISS. If this is successful regular contracted missions can begin [186].


Render of Dream Chaser in space

Dream Chaser in space

HL-20

Operator: NASA

Mission: Crewed spaceflight

First flight: None

Status: Cancelled


With the space shuttle 10 years old at the time, in the 90s, a new vehicle was requested by NASA to complement the space shuttle. In addition, this vehicle was proposed as the crew emergency rescue vehicle, which would be attached to the upcoming space station Freedom (which became the ISS). It would have a crew of between 2 and 8 people, launched using a Titan IV. But in addition, it should fit inside the shuttle payload bay[1,3]. Using inspiration from the Soviet BOR-4, the HL-20 was designed [178,181].

The HL-20, or Personnel launch system (PLS), was a small space plane with a wingspan of 7.2 and a length of 8.8m [178,179]. It had a dry mass of 7863 kg, a landing mass of 9392 kg and a launch mass of 28788 kg [180]. The propulsion system had enough propellant onboard for 335m/s Delta-V, 305m/s for orbital manoeuvring and 30m/s for space station operations. HL-20 had a suspended heat shield attached to the pressure vessel for re-entry. This thick graphite-polyamide honeycomb was the last layer. On top of this, there were thermal tiles for extra thermal shielding.


During the ascent, the HL-20 would monitor the Titan IV for any anomalies and separate if it detected any. As it is a lifting body, it would have the option to fly back to base. If flying back was impossible due to altitude or location, a parachute system would also be onboard. This was a conventional cluster of three 3.6m diameter ringsails. They would be deployed by three mortar-fired conical ribbon pilot chutes [178,180].

Part of the goal for the HL-20 was to make it as safe and cheap as possible. To achieve this, several changes were made with respect to the space shuttle, such as minimizing the amount of parts as much as possible. Also, the HL-20 used the improving state of technology and did away with the heavy hydraulic system and replaced it with an all-electric system to actuate the aerodynamic surfaces [179].


Render of the HL-20 on the run way

Only scale models to be tested in the wind tunnel were built. One full-scale model was made, which was used for further research on the crew compartment [179]. The HL-20 was eventually cancelled, and the design continued during the Dreamchaser.


X-20

Operator: USAF

Mission:  Spaceplane for the USAF

First flight: 1966 (planned, not happened)

Status:  Cancelled (1963)


With Operation Paperclip, the US not only brought over German aerospace engineers and scientists but also the ideas they had been working on during the war. One idea was the Aggregate program, which eventually, after many years, culminated in the Saturn V rocket. Another idea that they brought over was the Silverbird skip-glide bomber [3]. This was the basis to start the X-20 Dyna-Soar program.


The vehicle would have had a gross mass of 10125kg and be capable of carrying a 450kg payload, including one pilot. It has a height of 14.5m and a 6.3m wingspan [211]. It used a passive cooling system based on water to withstand the heat from re-entry. The X-20s mission profile would have had it perform a flight at 7.5km/s at 98 km altitude right at the edge of space [211,212].


In 1963, it was decided that the X-20 did not have a clear mission, and the program was cancelled as the space bomber mission itself was no longer discussed by the USAF [211,213]. However, the knowledge gathered during the X-20 program would eventually be used for the following space plane programs: Prime, Asset, X-23, and X-24 [211].

Render of the X20

HOPE-X

Operator: NASDA and NAL (both now part of JAXA)

Mission:  Bring astronauts and cargo to LEO

First flight:  

Status:  Cancelled


The JAXA HOPE-X space plane was a project that aimed to develop an experimental orbital vehicle for testing and validating technologies for future manned spaceflight. The project was started in the 1980s by a partnership between NASDA and NAL, both now part of JAXA. HOPE-X was intended to be one of the main Japanese contributions to the International Space Station, along with the Japanese Experiment Module. However, the project faced several challenges and delays and was eventually cancelled in 2003. One of the reasons for the cancellation was the reduction in scope that occurred in 1997 when it was decided that HOPE-X should be modified into an unmanned cargo vehicle with automated docking systems and a cargo bay. This was believed to be a cheaper and faster way to supply the ISS, which was suffering from problems with the US Space Shuttle program. However, this also meant that HOPE-X would lose its original purpose of being a precursor for a larger manned space plane. The HOPE-X space plane was supposed to be launched on Japan's H-IIA rocket, which had a payload capacity of about 3 metric tons (6,600 lb) to low Earth orbit. This was comparable to the Russian Progress spacecraft's capacity of about 2,500 kilograms (5,500 lb). The HOPE-X space plane had a length of 15.2 m (50 ft), a wingspan of 9.7 m (32 ft), and a mass of 14 t (31,000 lb). It was designed to reenter the atmosphere and land horizontally on a runway.


Schematic of JAXA HOPE-X

Scematic of HOPE-X

X-37

Operator: USAF

Mission: Unknown

First flight: 2010

Status: Active


The X-37 is a spacecraft operated by the United States Air Force capable of performing a gliding entry. The spacecraft flies classified missions and is launched on board an Atlas V or Falcon 9. During the landing, the X-37 uses its lift-generating capabilities to fly back to a runway where it lands like an aircraft. The X-37 can do this as the lift-over-drag ratio of the X-37 is higher at subsonic conditions compared to the Space Rider. The X-37 has had a troubled history where it was originally developed to fly in the Space Shuttle cargo bay. After the space shuttle's cancellation, the X37 was changed to be launched onboard a ULA Atlas V and the SpaceX Falcon 9. 


SpaceShipTwo

Operator: Virgin Galactic

Mission:  Suborbital flights

First flight:  2004 (SpaceShipOne), 2018 (SpaceShipTwo)

Status:  Active (SpaceShipTwo)

The development of SpaceShipTwo is plagued with issues. In 2007, an explosion occurred during motor testing, killing three employees and injuring three more. In October 2014, the VSS Enterprise crashed after the feathering system deployed during flight. This resulted in the death of co-pilot Michael Alsbury and injured pilot Peter Siebold. This crash marked the first fatality in spaceflight since the Columbia disaster.

The first spaceflight with passengers occurred in July 2021 during the suborbital space race with the New Shepard. During this flight, the spaceship deviated from the course, leading to a grounding of the spaceship. This ban was lifted in September of that year. A second crewed flight was performed in May 2023.


SpaceShipOne under the carrier aircraft
Crash site of VSS Enterprise

Crash site of the VSS Enterprise

SpaceShipOne under the carrier aircraft

The vehicle was further developed into SpaceShipTwo, a more capable vehicle that can perform suborbital spaceflight with six passengers. 


The SpaceShipOne vehicle of Virgin Galactic was developed for the Ansari X Prize back in 2007-2018. The rocket was conceived in 1994 and first flew in May 2003. The unique design consists of an air-launched spaceplane with a hybrid rocket motor. When returning from space, the vehicle 'folds in half' or feathers like a shuttlecock. This allows the vehicle to have natural stability, thus not requiring active control during re-entry. The first space flight of SpaceShipOne was performed on June 21, 2004 when Mike Melvill flew to 100.124 km. The two subsequent flights occurred on September 29, 2004, and October 4, 2004, which completed the requirements of the Ansari X Prize.