Spaceplane
Four examples of spaceplanes have successfully launched to orbit, reentered Earth's atmosphere, and landed: the U.S. Space Shuttle, Russian Buran, U.S. X-37,[2] and the Chinese Shenlong.
Another, Dream Chaser, is under development in the U.S. As of 2024 all past and current orbital spaceplanes launch vertically; some are carried as a payload in a conventional fairing, while the Space Shuttle used its own engines with the assistance of boosters and an external tank.
Spaceplanes do not necessarily have to fly by their own propulsion, but instead often glide with their inertia while using aerodynamic surfaces to maneuver in the atmosphere during descent and landing.
The flight trajectory required to reach orbit results in significant aerodynamic loads, vibrations, and accelerations, all of which have to be withstood by the vehicle structure.
[citation needed] Once on-orbit, a spaceplane must be supplied with power by solar panels and batteries or fuel cells, maneuvered in space, kept in thermal equilibrium, oriented, and communicated with.
[citation needed] Orbital spacecraft reentering the Earth's atmosphere must shed significant velocity, resulting in extreme heating.
[9] Suborbital spaceplanes fly lower energy trajectories that do not put as much stress on the spacecraft thermal protection system.
An air-breathing orbital spaceplane would have to fly what is known as a 'depressed trajectory,' which places the vehicle in the high-altitude hypersonic flight regime of the atmosphere for an extended period of time.
The Space Shuttle was launched vertically, like a conventional rocket, with the two SRBs operating in parallel with the orbiter's three main engines, which were fueled from the ET.
'Air and Space Ship'),[15] was a Soviet and later Russian reusable spacecraft project that began in 1974 at the Central Aerohydrodynamic Institute in Moscow and was formally suspended in 1993.
HYFLEX was a miniaturized suborbital demonstrator launched in 1996, flying to 110 km altitude, achieving hypersonic flight, and successfully reentering the atmosphere.
Notable early designs include a spaceplane equipped with wings made of combustible alloys that it would burn during its ascent, and the Silbervogel bomber concept.
The result, the Boeing X-20 Dyna-Soar, was to have been the first orbital spaceplane, but was canceled in the early 1960s[37][38] in lieu of NASA's Project Gemini and the U.S. Air Force's crewed spaceflight program.
[40] Though attempts to revive the paraglider concept persisted within NASA and North American Aviation, in 1964 development was definitively discontinued due to the expense of overcoming the technical hurdles.
The Rockwell X-30 National Aero-Space Plane (NASP), begun in the 1980s, was an attempt to build a scramjet vehicle capable of operating like an aircraft and achieving orbit like the shuttle.
Introduced to the public in 1986, the concept was intended to reach Mach 25, enabling flights between Dulles Airport to Tokyo in two hours, while also being capable of low Earth orbit.
[44] The Lockheed Martin X-33 was a 1/3 scale prototype made as part of an attempt by NASA to build a SSTO hydrogen-fuelled spaceplane VentureStar that failed when the hydrogen tank design could not be constructed as intended.
[citation needed] On 5 March 2006, Aviation Week & Space Technology published a story purporting to be the "outing" of a highly classified U.S. military two-stage-to-orbit spaceplane system with the code name Blackstar.
The Buran orbital vehicle programme was developed in response to the U.S. Space Shuttle program, which raised considerable concerns among the Soviet military and especially Defense Minister Dmitry Ustinov.
[50][51] The Multi-Unit Space Transport And Recovery Device (MUSTARD) was a concept explored by the British Aircraft Corporation (BAC) around 1968 for launching payloads weighing as much as 2,300 kg (5,000 lb) into orbit.
[52] In the 1980s, British Aerospace began development of HOTOL, an SSTO spaceplane powered by a revolutionary SABRE air-breathing rocket engine, but the project was canceled due to technical and financial uncertainties.
[54] One NASA analysis showed possible issues with the hot rocket exhaust plumes causing heating of the tail structure at high Mach numbers.
[59][60] Hopper was one of several proposals for a European reusable launch vehicle (RLV) planned to cheaply ferry satellites into orbit by 2015.
[64] HOPE was a Japanese experimental spaceplane project designed by a partnership between NASDA and NAL (both now part of JAXA), started in the 1980s.
[citation needed] AVATAR (Aerobic Vehicle for Hypersonic Aerospace Transportation; Sanskrit: अवतार) was a concept study for an uncrewed single-stage reusable spaceplane capable of horizontal takeoff and landing, presented to India's Defence Research and Development Organisation.
[69][70][71] A test project, the Intermediate eXperimental Vehicle (IXV), has demonstrated lifting reentry technologies and will be extended under the PRIDE programme.
[72] The Daimler-Chrysler Aerospace RLV is a small reusable spaceplane prototype for the ESA Future Launchers Preparatory Programme/FLTP program.
[83] The RLV prototype was dropped from a Chinook helicopter at an altitude of 4.5 kms and was made to autonomously glide down to a purpose-built runway at the Chitradurga Aeronautical Test Range, Karnataka.
[84] As of 2018, Japan is developing the Winged Reusable Sounding rocket (WIRES), which if successful, may be used as a recoverable first-stage or as a crewed sub-orbital spaceplane.
[87] The Dream Chaser was originally started in 2004 as a project of SpaceDev, a company that was later acquired by the Sierra Nevada Corporation (SNC) in 2008.
