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78-546: The DC-X , short for Delta Clipper or Delta Clipper Experimental , was an uncrewed prototype of a reusable single-stage-to-orbit launch vehicle built by McDonnell Douglas in conjunction with the United States Department of Defense 's Strategic Defense Initiative Organization (SDIO) from 1991 to 1993. Starting 1994 until 1995, testing continued through funding of the US civil space agency NASA . In 1996,

156-519: A fire which severely burned the DC-XA, causing such extensive damage that repairs were impractical. In a post-accident report, NASA's Brand Commission blamed the accident on a burnt-out field crew who had been operating under on-again/off-again funding and constant threats of outright cancellation. The crew, many of them originally from the SDIO program, were also highly critical of NASA's "chilling" effect on

234-452: A fire. Post flight inspection of the landing struts revealed that the pneumatic nitrogen actuation line to the failed strut was disconnected. This line was normally disconnected from the strut during pre-flight testing, when each strut was extended and retracted by a ground cart. Normally the structural damage from such a fall would constitute only a setback, but the LOX from the leaking tank fed

312-584: A flight test program with experimental vehicles . These subsequently led to the development of the Falcon 9 reusable rocket launcher. Retro rocket A retrorocket (short for retrograde rocket ) is a rocket engine providing thrust opposing the motion of a vehicle, thereby causing it to decelerate. They have mostly been used in spacecraft , with more limited use in short-runway aircraft landing. New uses are emerging since 2010 for retro-thrust rockets in reusable launch systems . Rockets were fitted to

390-518: A fully reusable successor to the Saturn V rocket, having the capacity of transporting up to 450–910 t (990,000–2,000,000 lb) to orbit. See also Sea Dragon , and Douglas SASSTO . The BAC Mustard was studied starting in 1964. It would have comprised three identical spaceplanes strapped together and arranged in two stages. During ascent the two outer spaceplanes, which formed the first stage, would detach and glide back individually to earth. It

468-666: A higher anticipated launch cadence and landing sites for the new generation of vehicles. Reusable launch systems may be either fully or partially reusable. Several companies are currently developing fully reusable launch vehicles as of March 2024. Each of them is working on a two-stage-to-orbit system. SpaceX is testing Starship , which has been in development since 2016 and has made an initial test flight in April 2023 and 5 more flights as of November 2024. Blue Origin , with Project Jarvis , began development work by early 2021, but has announced no date for testing and have not discussed

546-486: A method to drop heavy equipment or vehicles from aircraft flying at high speeds and altitudes, the project turned out to be a disaster and was largely forgotten after the war. Although some of the tests turned out to be successful, Hajile was too unpredictable to be used in conventional warfare, and by the time the war drew to a close, with no chance to put the project into action, it was shelved. Later Soviet experiments used this technique, braking large air-dropped cargos after

624-599: A new DC-X at $ 50 million, cheap by NASA standards, but NASA decided not to rebuild the craft in light of budget constraints. Instead, NASA focused development on the Lockheed Martin VentureStar which it felt answered some criticisms of the DC-X, specifically the airplane-like landing of the VentureStar, which many NASA engineers preferred over the vertical landing of the DC-X. Just a few years later,

702-456: A parachute descent. When a spacecraft in orbit is slowed sufficiently, its altitude decreases to the point at which aerodynamic forces begin to rapidly slow the motion of the vehicle, and it returns to the ground. Without retrorockets, spacecraft would remain in orbit until their orbits naturally slow, and reenter the atmosphere at a much later date; in the case of crewed flights, long after life support systems have been expended. Therefore, it

780-694: A reusable space vehicle (a spaceplane ) as well as a part of its launch system. More contemporarily the Falcon 9 launch system has carried reusable vehicles such as the Dragon 2 and X-37 , transporting two reusable vehicles at the same time. Contemporary reusable orbital vehicles include the X-37, the Dream Chaser , the Dragon 2, the Indian RLV-TD and the upcoming European Space Rider (successor to

858-541: A slight overlap. These were mounted in the retrograde section of the adapter module, located just behind the capsule's heat shield. For lunar flights, the Apollo command and service module did not require retrorockets to return the command module to Earth, as the flight path took the module through the atmosphere , using atmospheric drag to reduce velocity. The test flights in Earth orbit required retrograde propulsion, which

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936-436: A spacecraft to enter an orbit around such a body, when otherwise it would scoot past and off into space again. As pointed out above (in connection with Project Apollo ) the main rocket on a spacecraft can be re-oriented to serve as a retrorocket. The Soyuz capsule uses small rockets for the last phase of landing. New uses for retro-thrust rockets emerged since 2010 for reusable launch systems . After second stage separation,

1014-472: A variant's basic operation would have to be "reversed"; from taking off and then landing, to landing first then taking off. Yet, if this could be accomplished on Earth, the weaker gravity found at both Mars and the Moon would make for dramatically greater payload capabilities, particularly at the latter destination. Some people proposed design changes include using an oxidizer/fuel combination that does not require

1092-423: Is an in-air-capture tow back system, advocated by a company called EMBENTION with its FALCon project. Vehicles that land horizontally on a runway require wings and undercarriage. These typically consume about 9-12% of the landing vehicle mass, which either reduces the payload or increases the size of the vehicle. Concepts such as lifting bodies offer some reduction in wing mass, as does the delta wing shape of

1170-484: Is assumed that the bulk density of the first stage (without propellant) is less than the bulk density of air. Upon returning from flight, such a first stage remains floating in the air (without touching the surface of the Earth). This will ensure that the first stage is retained for reuse. Increasing the size of the first stage increases aerodynamic losses. This results in a slight decrease in payload. This reduction in payload

1248-607: Is compensated for by the reuse of the first stage. Reusable stages weigh more than equivalent expendable stages . This is unavoidable due to the supplementary systems, landing gear and/or surplus propellant needed to land a stage. The actual mass penalty depends on the vehicle and the return mode chosen. After the launcher lands, it may need to be refurbished to prepare it for its next flight. This process may be lengthy and expensive. The launcher may not be able to be recertified as human-rated after refurbishment, although SpaceX has flown reused Falcon 9 boosters for human missions. There

1326-525: Is critical that spacecraft have extremely reliable retrorockets. Due to the high reliability demanded by de-orbiting retrorockets, Mercury spacecraft used a trio of solid fuel, 1000  lbf (4.5  kN ) thrust retrorockets that fired for 10 seconds each, strapped to the heat shield on the bottom of the spacecraft. One was sufficient to return the spacecraft to Earth if the other two failed. Gemini used four rockets, each 2,500 pounds-force (11 kN), burning for 5.5 seconds in sequence, with

1404-430: Is eventually a limit on how many times a launcher can be refurbished before it has to be retired, but how often a launcher can be reused differs significantly between the various launch system designs. With the development of rocket propulsion in the first half of the twentieth century, space travel became a technical possibility. Early ideas of a single-stage reusable spaceplane proved unrealistic and although even

1482-533: Is to be caught by arms after performing most of the typical steps of a retrograde landing. Blue Origin 's New Shepard suborbital rocket also lands vertically back at the launch site. Retrograde landing typically requires about 10% of the total first stage propellant, reducing the payload that can be carried due to the rocket equation . There is also the concept of a launch vehicle with an inflatable, reusable first stage. The shape of this structure will be supported by excess internal pressure (using light gases). It

1560-553: The Douglas DC-1 . The vehicle is inspired by the designs of McDonnell Douglas engineer Philip Bono , who saw single stage to orbit VTOL lifters as the future of space travel. The Delta Clipper was very similar to Bono's SASSTO vehicle from 1967. Bono died less than three months before the DC-X's first test flight. SDIO wanted a "suborbital, recoverable rocket (SRR) capable of lifting up to 3,000 pounds (1361 kg) of payload to an altitude of 1.5 million feet (457 km); returning to

1638-550: The Falcon 9 and the New Shepard employ retrograde burns for re-entry, and landing. Reusable systems can come in single or multiple ( two or three ) stages to orbit configurations. For some or all stages the following landing system types can be employed. These are landing systems that employ parachutes and bolstered hard landings, like in a splashdown at sea or a touchdown at land. The latter may require an engine burn just before landing as parachutes alone cannot slow

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1716-544: The IXV ). As with launch vehicles, all pure spacecraft during the early decades of human capacity to achieve spaceflight were designed to be single-use items. This was true both for satellites and space probes intended to be left in space for a long time, as well as any object designed to return to Earth such as human-carrying space capsules or the sample return canisters of space matter collection missions like Stardust (1999–2006) or Hayabusa (2005–2010). Exceptions to

1794-512: The S-IC and S-II stages off from the rest of the vehicle after their respective shutdowns during the Saturn V's launch to Earth orbit. Meanwhile, the succeeding stage may have posigrade ullage rockets , both to aid separation and ensure good starting of liquid-fuel engines. Retrorockets are also used in landing spacecraft on other astronomical bodies, such as the Moon and Mars , as well as enabling

1872-699: The Space Launch System are considered to be retrofitted with such heat shields to salvage the expensive engines, possibly reducing the costs of launches significantly. Heat shields allow an orbiting spacecraft to land safely without expending very much fuel. They need not take the form of inflatable heat shields, they may simply take the form of heat-resistant tiles that prevent heat conduction . Heat shields are also proposed for use in combination with retrograde thrust to allow for full reusability as seen in Starship . Reusable launch system stages such as

1950-537: The Space Shuttle . Systems like the McDonnell Douglas DC-X (Delta Clipper) and those by SpaceX are examples of a retrograde system. The boosters of Falcon 9 and Falcon Heavy land using one of their nine engines. The Falcon 9 rocket is the first orbital rocket to vertically land its first stage on the ground. The first stage of Starship is planned to land vertically, while the second

2028-470: The SpaceX Falcon 9 development was "... continuing the great work of the DC-X project." Some NASA engineers have noted that the DC-X could provide a solution for a crewed Mars lander. Had a DC-type craft been developed that operated as an SSTO in Earth's gravity well , even if with only a minimum 4–6 crew capacity, variants of it might prove extremely capable for both Mars and Moon missions. Such

2106-673: The hostages in Iran resulted in the construction of two modified Lockheed C-130 Hercules , designated YMC-130H, which featured retro-rockets to allow it to perform extremely short landings. As part of the plan, these aircraft would land in the Shahid Shiroudi Stadium near the US Embassy in Tehran and use the retrorockets to come to a stop. One aircraft was destroyed in a crash during a test flight without any fatalities, and

2184-512: The 1950s ( Rocketship X-M , Destination Moon , and others), but not seen in real world designs of space vehicles. It would take off vertically like standard rockets , but also land vertically with the nose up. This design used attitude control thrusters and retro rockets to control the descent, allowing the craft to begin atmospheric entry nose-first, but then roll around and touch down on landing struts at its base. The craft could be refueled where it landed, and take off again from exactly

2262-546: The 1970s, the first reusable launch vehicle, the Space Shuttle , was developed. However, in the 1990s, due to the program's failure to meet expectations, reusable launch vehicle concepts were reduced to prototype testing. The rise of private spaceflight companies in the 2000s and 2010s lead to a resurgence of their development, such as in SpaceShipOne , New Shepard , Electron , Falcon 9 , and Falcon Heavy . Many launch vehicles are now expected to debut with reusability in

2340-649: The 2020s, such as Starship , New Glenn , Neutron , Soyuz-7 , Ariane Next , Long March , Terran R , and the Dawn Mk-II Aurora. The impact of reusability in launch vehicles has been foundational in the space flight industry. So much so that in 2024, the Cape Canaveral Space Force Station initiated a 50 year forward looking plan for the Cape that involved major infrastructure upgrades (including to Port Canaveral ) to support

2418-403: The DC-X project was minimized maintenance and ground support. To this end, the craft was highly automated and required only three people in its control center (two for flight operations and one for ground support). Construction of the DC-X started in 1991 at McDonnell Douglas' Huntington Beach facility. The aeroshell was custom-constructed by Scaled Composites , but the majority of the spacecraft

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2496-480: The DC-X technology was completely transferred to NASA, which upgraded the design for improved performance to create the DC-XA . After a test flight of DC-XA in 1996 resulted in a fire, the project was canceled. Despite its cancellation, the program inspired later reusable launch systems . Michael D. Griffin has since praised the program as "government R&D at its finest." According to writer Jerry Pournelle : "DC-X

2574-563: The European Commission 's RETALT project and the China National Space Administration 's Long March 8 are also pursuing retro-thrust re-entry for reusable boosters. New Shepard is a reusable single-stage suborbital rocket where the booster uses its main engine to land again after a flight. The capsule slows its descent with parachutes and uses retrorockets to slow down just before reaching

2652-611: The Shuttle technology, to be demonstrated under the X-33 and X-34 programs, which were both cancelled in the early 2000s due to rising costs and technical issues. The Ansari X Prize contest was intended to develop private suborbital reusable vehicles. Many private companies competed, with the winner, Scaled Composites , reaching the Kármán line twice in a two-week period with their reusable SpaceShipOne . In 2012, SpaceX started

2730-697: The aircraft is thought of as the first stage of the launch vehicle. An example of this configuration is the Orbital Sciences Pegasus . For suborbital flight the SpaceShipTwo uses for liftoff a carrier plane, its mothership the Scaled Composites White Knight Two . Rocket Lab is working on Neutron , and the European Space Agency is working on Themis . Both vehicles are planned to recover

2808-452: The atmosphere, parachutes or retrorockets may also be needed to slow it down further. Reusable parts may also need specialized recovery facilities such as runways or autonomous spaceport drone ships . Some concepts rely on ground infrastructures such as mass drivers to accelerate the launch vehicle beforehand. Since at least in the early 20th century, single-stage-to-orbit reusable launch vehicles have existed in science fiction . In

2886-531: The craft down enough to prevent injury to astronauts. This can be seen in the Soyuz capsule. Though such systems have been in use since the beginning of astronautics to recover space vehicles, only later have the vehicles been reused. E.g.: Single or main stages, as well as fly-back boosters can employ a horizontal landing system. These vehicles land on earth much like a plane does, but they usually do not use propellant during landing. Examples are: A variant

2964-428: The craft needs to have considerable cross-range maneuverability, something that is difficult to arrange with a large smooth surface. The Delta Clipper design thus used a nose-first re-entry with flat sides on the fuselage and large control flaps to provide the needed cross range capability. Experiments with the control of such a re-entry profile had never been tried, and were a major focus of the project. Another focus of

3042-404: The east about 20 to 30 degrees in that time; or for a launch from the southern United States, about 1,500 miles (2,400 km). If the spacecraft is launched to the east this does not present a problem, but for the polar orbits required of military spacecraft , when the orbit is complete the spacecraft overflies a point far to the west of the launch site. In order to land back at the launch site,

3120-492: The far more promising Skylon design, which remains in development. From the late 1990s to the 2000s, the European Space Agency studied the recovery of the Ariane 5 solid rocket boosters. The last recovery attempt took place in 2009. The commercial ventures, Rocketplane Kistler and Rotary Rocket , attempted to build reusable privately developed rockets before going bankrupt. NASA proposed reusable concepts to replace

3198-431: The first practical rocket vehicles ( V-2 ) could reach the fringes of space, reusable technology was too heavy. In addition, many early rockets were developed to deliver weapons, making reuse impossible by design. The problem of mass efficiency was overcome by using multiple expendable stages in a vertical launch multistage rocket . USAF and NACA had been studying orbital reusable spaceplanes since 1958, e.g. Dyna-Soar , but

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3276-476: The first reusable stages did not fly until the advent of the US Space Shuttle in 1981. Perhaps the first reusable launch vehicles were the ones conceptualized and studied by Wernher von Braun from 1948 until 1956. The Von Braun Ferry Rocket underwent two revisions: once in 1952 and again in 1956. They would have landed using parachutes. The General Dynamics Nexus was proposed in the 1960s as

3354-501: The first stage engines, while the tank is expended. The engines would splashdown on an inflatable aeroshell , then be recovered. On 23 February 2024, one of the nine Merlin engines a powering a Falcon 9 launched for the 22nd time, making it the most reused liquid fuel engine used in an operational manner, having already surpassed Space Shuttle Main Engine number 2019's record of 19 flights. As of 2024, Falcon 9 and Falcon Heavy are

3432-497: The first stage of SpaceX 's Falcon 9 and Falcon Heavy rockets uses one to three of the main engines in order to decelerate for propulsive landing . The first stage is then recovered, refurbished and prepared for the next flight. The boosters of other orbital rockets are routinely destroyed after a single use by atmospheric reentry and high-speed impact in the ocean. Companies like Blue Origin with their New Glenn , Link Space with their New Line 1 and national projects like

3510-490: The first stage. So far, most launch systems achieve orbital insertion with at least partially expended multistaged rockets , particularly with the second and third stages. Only the Space Shuttle has achieved a reuse of the orbital insertion stage, by using the engines and fuel tank of its orbiter . The Buran spaceplane and Starship spacecraft are two other reusable spacecraft that were designed to be able to act as orbital insertion stages and have been produced, however

3588-443: The former only made one uncrewed test flight before the project was cancelled, and the latter is not yet operational, having completed four orbital test flights , as of June 2024, which achieved all of its mission objectives at the fourth flight. Launch systems can be combined with reusable spaceplanes or capsules. The Space Shuttle orbiter , SpaceShipTwo , Dawn Mk-II Aurora, and the under-development Indian RLV-TD are examples for

3666-670: The general rule for space vehicles were the US Gemini SC-2 , the Soviet Union spacecraft Vozvraschaemyi Apparat (VA) , the US Space Shuttle orbiter (mid-1970s-2011, with 135 flights between 1981 and 2011) and the Soviet Buran (1980-1988, with just one uncrewed test flight in 1988). Both of these spaceships were also an integral part of the launch system (providing launch acceleration) as well as operating as medium-duration spaceships in space . This began to change in

3744-487: The ground, in order to retrieve and reuse the vehicle. As of 2021 , SpaceX is building and testing the Starship spaceship to be capable of surviving multiple hypersonic reentries through the atmosphere so that they become truly reusable long-duration spaceships; no Starship operational flights have yet occurred. With possible inflatable heat shields , as developed by the US (Low Earth Orbit Flight Test Inflatable Decelerator - LOFTID) and China, single-use rockets like

3822-410: The ground. SpaceX's Starship launch vehicle recovers its Super Heavy booster in a similar manner to Falcon 9, lighting thirteen engines, before shutting down ten of these engines for the final descent. The second stage, after reentry, lights its three inner engines and descends to either a splashdown or a catch. Operation Credible Sport , a plan put forward by the US government in 1979 to rescue

3900-417: The heat load is spread out over a larger area. Finally, this profile would not require the spacecraft to "flip around" for landing. The military role made this infeasible, however. One desired safety requirement for any spacecraft is the ability to "abort once around", that is, to return for a landing after a single orbit. Since a typical low Earth orbit takes about 90 to 120 minutes, the Earth will rotate to

3978-460: The horizon, under control of the main engines. It then exercised a controlled rotation to a nose up attitude, and executed a powered soft landing. This maneuver showed that a single stage to orbit vehicle could efficiently return from orbit using aerodynamic braking in a forward attitude, and then rotate to a base first powered landing at a spaceport. Its next flight, on 31 July 1996, proved to be its last. The launch and flight portion of this mission

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4056-419: The launch site for a precise soft landing; with the capability to launch for another mission within three to seven days". DC-X Specifications: Built as a one-third-size scale prototype, the DC-X was never designed to achieve orbital altitudes or velocity, but instead to demonstrate the concept of vertical take off and landing . The vertical take off and landing concept was popular in science fiction films from

4134-641: The mid-2010s. In the 2010s, the space transport cargo capsule from one of the suppliers resupplying the International Space Station was designed for reuse, and after 2017, NASA began to allow the reuse of the SpaceX Dragon cargo spacecraft on these NASA-contracted transport routes. This was the beginning of design and operation of a reusable space vehicle . The Boeing Starliner capsules also reduce their fall speed with parachutes and deploy an airbag shortly before touchdown on

4212-649: The nose of some models of the DFS 230 , a World War II German Military glider . This enabled the aircraft to land in more confined areas than would otherwise be possible during an airborne assault. Another World War II development was the British Hajile project, initiated by the British Admiralty's Directorate of Miscellaneous Weapons Development . Originally a request from the British Army as

4290-529: The only orbital rockets to reuse their boosters, although multiple other systems are in development. All aircraft-launched rockets reuse the aircraft. Other than that a range of non-rocket liftoff systems have been proposed and explored over time as reusable systems for liftoff, from balloons to space elevators . Existing examples are systems which employ winged horizontal jet-engine powered liftoff. Such aircraft can air launch expendable rockets and can because of that be considered partially reusable systems if

4368-534: The only reusable configurations in use. The historic Space Shuttle reused its Solid Rocket Boosters , its RS-25 engines and the Space Shuttle orbiter that acted as an orbital insertion stage, but it did not reuse the External Tank that fed the RS-25 engines. This is an example of a reusable launch system which reuses specific components of rockets. ULA’s Vulcan Centaur was originally designed to reuse

4446-442: The program after the last DC-X flight in 1995. In contrast to the original concept of the DC-X demonstrator, NASA applied a series of major upgrades to test new technologies. In particular, the oxygen tank was replaced by a lightweight (alloy 1460 equivalent of alloy 2219) aluminium-lithium alloy tank from Russia, and the hydrogen tank by a graphite-epoxy composite design. The control system was likewise improved. The upgraded vehicle

4524-510: The program, and the masses of paperwork NASA demanded as part of the testing regimen. NASA had taken on the project grudgingly after having been "shamed" by its very public success under the direction of the SDIO. Its continued success was cause for considerable political in-fighting within NASA due to it competing with their "home grown" Lockheed Martin X-33 / VentureStar project. Pete Conrad priced

4602-407: The project publicly. Stoke Space is also developing a rocket which is planned to be reusable. As of October 2024 , Starship is the only launch vehicle intended to be fully reusable that has been fully built and tested. The most recent test flight was on October 13, 2024, in which the vehicle completed a suborbital launch and landed both stages for the second time. The Super Heavy booster

4680-656: The relatively extensive ground support required for the liquid hydrogen and liquid oxygen that DC-X utilized, and adding a fifth leg for increased stability during and after landing. Reusable launch system Reusable launch vehicles may contain additional avionics and propellant , making them heavier than their expendable counterparts. Reused parts may need to enter the atmosphere and navigate through it, so they are often equipped with heat shields , grid fins , and other flight control surfaces . By modifying their shape, spaceplanes can leverage aviation mechanics to aid in its recovery, such as gliding or lift . In

4758-628: The repeated failure of the Venturestar project, especially the composite LH2 ( liquid hydrogen ) tank, led to program cancellation. The original DC-X was built in 21 months for a cost of $ 60 million. This is equivalent to $ 120 million in present-day terms. Several engineers who worked on the DC-X were hired by Blue Origin , and their New Shepard vehicle was inspired by the DC-X design. The DC-X provided inspiration for many elements of Armadillo Aerospace 's, Masten Space Systems 's, and TGV Rockets 's spacecraft designs. Elon Musk stated that

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4836-405: The same position — a trait that allowed unprecedented turnaround times. In theory a base-first re-entry profile would be easier to arrange. The base of the craft would already need some level of heat protection to survive the engine exhaust, so adding more protection would be easy enough. More importantly, the base of the craft is much larger than the nose area, leading to lower peak temperatures as

4914-616: The small prototype should be called the DC-X, X being the US Air Force designation for "experimental". This would be followed by the "DC-Y", with Y being the USAF designation for pre-production test aircraft and prototypes (e.g. YF-16 ). Finally the production version would be known as the "DC-1". The name "Delta Clipper" was chosen to result in the acronym "DC" to draw a connection with the Douglas "DC Series" of airliners, beginning with

4992-481: The uncertainties of the design, the basic plan was to produce a deliberately simple test vehicle and to "fly a little, break a little" in order to gain experience with fully reusable quick-turnaround spacecraft. As experience was gained with the vehicle, a larger prototype would be built first for sub-orbital and then orbital tests. Finally a commercially acceptable vehicle would be developed from these prototypes. In keeping with general aircraft terminology, they proposed

5070-464: The vehicle set its altitude and duration records, 3,140 metres (10,300 ft) and 142 seconds of flight time. Also, during the 8 June flight, the vehicle executed the first planned rotation maneuver for a rocket, where it transitioned from nose first forward flight to controlled backwards flight. At the apex of this rotation maneuver, DC-XA slowed itself by rotating to a backwards orientation, and flew backwards, base first, with its nose 10 degrees below

5148-682: Was at the ground-based controls for some flights. These tests were conducted at the White Sands Missile Range in New Mexico. However, further funding was provided by NASA and the Advanced Research Projects Agency (ARPA). The test program restarted on 20 June 1994 with a 136-second flight. The next flight, 27 June 1994, suffered a minor inflight explosion, but the craft successfully executed an abort and autoland. Testing restarted after this damage

5226-470: Was built from commercial off-the-shelf parts, including the engines and flight control systems. The DC-X first flew, for 59 seconds, on 18 August 1993; it was claimed that it was the first time a rocket had landed vertically on Earth. It flew two more flights 11 September and 30 September, when funding ran out as a side effect of the winding down of the SDIO program; in addition the program was considered far-fetched by detractors. Apollo astronaut Pete Conrad

5304-479: Was called the DC-XA , renamed the Clipper Advanced / Clipper Graham , and resumed flight in 1996. The first flight of the DC-XA test vehicle was made on 18 May 1996 and resulted in a minor fire when the deliberate "slow landing" resulted in overheating of the aeroshell. The damage was quickly repaired and the vehicle flew two more times on 7 and 8 June, a 26-hour turnaround. On the second of these flights

5382-461: Was canceled after the last study of the design in 1967 due to a lack of funds for development. NASA started the Space Shuttle design process in 1968, with the vision of creating a fully reusable spaceplane using a crewed fly-back booster . This concept proved expensive and complex, therefore the design was scaled back to reusable solid rocket boosters and an expendable external tank . Space Shuttle Columbia launched and landed 27 times and

5460-689: Was canceled in 1993. In the late 1980s a fully reusable version of the Energia rocket, the Energia II, was proposed. Its boosters and core would have had the capability of landing separately on a runway. In the 1990s the McDonnell Douglas Delta Clipper VTOL SSTO proposal progressed to the testing phase. The DC-X prototype demonstrated rapid turnaround time and automatic computer control. In mid-1990s, British research evolved an earlier HOTOL design into

5538-467: Was caught successfully by the "chopstick system" on Orbital Pad A for the first time. The Ship completed its second successful reentry and returned for a controlled splashdown in the Indian Ocean. The test marked the second instance that could be considered meeting all requirements to be fully reusable. Partial reusable launch systems, in the form of multiple stage to orbit systems have been so far

5616-500: Was conceived in my living room and sold to National Space Council Chairman Dan Quayle by General Graham , Max Hunter and me." According to Max Hunter, however, he had tried hard to convince Lockheed Martin of the concept's value for several years before he retired. Hunter had written a paper in 1985 entitled "The Opportunity", detailing the concept of a Single-Stage-To-Orbit spacecraft built with low-cost "off-the-shelf" commercial parts and then available technology, but Lockheed Martin

5694-403: Was fixed, and three more flights were carried out on 16 May 1995, 12 June, and 7 July. On the last flight a hard landing cracked the aeroshell. By this point funding for the program had already been cut, and there were no funds for the needed repairs. The altitude record for the DC-X was 2,500 m, set during its last flight before being upgrading to the DC-XA, on 7 July 1995. NASA agreed to take on

5772-407: Was flawless, however, after slowing to a perfect touchdown, only 3 of the 4 landing struts extended. The vehicle could not balance on 3 struts, and slowly fell sideways on the landing pad. When the side of the vehicle struck the concrete pad, the main liquid oxygen tank cracked open and leaked LOX onto the pad. This LOX contacted a small amount of glowing material on the base heat shield, and started

5850-444: Was lost with all crew on the 28th landing attempt; Challenger launched and landed 9 times and was lost with all crew on the 10th launch attempt; Discovery launched and landed 39 times; Atlantis launched and landed 33 times; Endeavour launched and landed 25 times. In 1986 President Ronald Reagan called for an air-breathing scramjet National Aerospace Plane (NASP)/ X-30 . The project failed due to technical issues and

5928-439: Was not interested enough to fund such a program themselves. On February 15, 1989, Pournelle, Graham and Hunter were able to procure a meeting with Vice-President Dan Quayle. They successfully "sold" the idea to SDIO by noting that any space-based weapons system would need to be serviced by a spacecraft that was far more reliable than the Space Shuttle , and offer lower launch costs and have much better turnaround times. Given

6006-433: Was provided by the large Service Propulsion Engine on the service module. The same engine was used as a retrorocket to slow the spacecraft for lunar orbit insertion . The Apollo Lunar Module used its descent stage engine to drop from orbit and land on the Moon. The Space Shuttle Orbital Maneuvering System provided the vehicle with a pair of powerful liquid-fueled rockets for both reentry and orbital maneuvering. One

6084-454: Was sufficient for a successful reentry, and if both systems were to fail, the reaction control system could slow the vehicle enough for reentry. To ensure clean separation and prevent contact, multistage rockets such as the Titan II , Saturn I , Saturn IB , and Saturn V may have small retrorockets on lower stages, which ignite upon stage separation. For example, they were used to back

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