Scramjet programs

This page describes a number of research and testing programs for the development of supersonic combustion ramjets (scramjets) Many of these programs have their own pages, but an attempt is made here to provide a short overview of a large number of programs. They include national and international collaborations, and civilian and military programs.

Scramjet programs

X-15

When the second X-15 aircraft (piloted by Jack McKay) crashed on flight 74, it was damaged but survived well enough to be rebuilt. North American Aviation rebuilt it as the X-15-A2. Among other things, one of the changes was provisions for a dummy scramjet to test if wind tunnel testing was correct. Unfortunately, on the final flight of the X-15-A2 (flight 188), the shock waves sent out by the scramjet at Mach 6.7 caused extremely intense heating of over convert|2700|°F|°C. This then drilled into the ventral fin and melted large holes. The plane survived but never flew again. Test data was limited due to the limited flights of the scramjet before the X-15-A2 and the X-15 project on the whole were cancelled.fn|1

CRAM

From 1962–1978, the Johns Hopkins Applied Physics Laboratory (APL) undertook a classified program (declassified in 1993) to develop a family of missiles called SCRAMfn|8 (Supersonic Combustion RAmjet Missile). They were intended to fit on to the Talos MK12 launcher system or the Terrier MK10 launcher. Testing of engine modules in a direct-connect, and a free-jet, facility took place at a variety of Mach numbers and pressures (altitudes). These included Mach 4 (24,000 ft), Mach 5.3 (46,000 ft), Mach 7.8 (67,000 ft) and Mach 10 (88,000 ft). Tests showed that acceptable combustion efficiency was only achieved with over 20% pentaborane (B5H9) in MCPD (C12H16). Tests with pure pentaborane (HiCal) showed that a net thrust could be achieved at Mach 7. An accelerative capability equivalent to 11"g" was observed for Mach 5 flight at sea level.

NASP

In 1986 United States president Ronald Reagan announced the National Aerospace Plane (NASP) program, intended to develop two X-30 aircraft capable of single stage to orbit (SSTO), as well as horizontal takeoff and landing from conventional runways. The aircraft was to be a hydrogen fuelled air-breathing space plane, with a low speed accelerator system to bring the aircraft up to Mach 3, where the main dual-mode scramjet engines (ramjet/scramjet) would take over. At the edge of the atmosphere, a rocket was to take over and provide the final energy for orbital insertion. It was based on a classified DARPA research program called Copper Canyon. This research program suggested that Mach 25 might be possible. As the program proceeded it became clear that Mach 17 was probably the limit, whilst the weight penalty and complexity of the skin heat exchanger and other propulsion systems was going to be substantial. The program was established by the secretary of defence in 1985, and was funded to the end of FY1994, when the decision was made that the 15 billion dollars required to build the two X-30 test craft were excessive.

Although the more visible parts of the program were cancelled, NASP provided a large amount of basic research, which flowed into following projects. For example The NASP reaction modelfn|7 for hydrogen combustion in air (31 reactions, 16 species), is still extensively used where computational power is sufficient not to have to use reduced reaction models.

HyShot

On July 30, 2002, the University of Queensland's HyShot team (and international partners) conducted the first ever successful test flight of a scramjet.

The team took a unique approach to the problem of accelerating the engine to the necessary speed by using an Terrier-Orion sounding rocket to take the aircraft up on a parabolic trajectory to an altitude of 314 km. As the craft re-entered the atmosphere, it dropped to a speed of Mach 7.6. The scramjet engine then started, and it flew at about Mach 7.6 for 6 seconds. [http://www.abc.net.au/science/slab/hyshot/default.htm] . This was achieved on a lean budget of just A$1.5 million (US $1.1 million), a tiny fraction of NASA's US $250 million to develop the X-43A. This involved many of the same researchers involved in the University of Queensland report in 1995 of the first development of a scramjet that achieved more thrust than dragfn|2.

On Saturday, March 25, 2006 researchers at the University of Queensland conducted another successful test flight of a HyShot Scramjet at the Woomera Rocket Range in South Australia. The Hyshot III with its £1,200,000 engine made an apparently successful flight (and planned crash landing) reaching in the order of 7.6 Mach. [http://news.bbc.co.uk/1/low/sci/tech/4832254.stm]

NASA has partially explained the tremendous difference in cost between the two projects by pointing out that the American vehicle has an engine fully incorporated into an airframe with a full complement of flight control surfaces available.

In the second Hyshot mission, no net thrust was achieved. (The thrust was less than the drag.) [ [http://www.uq.edu.au/hypersonics/?page=19501 Center for Hypersonics- Hyshot] ]

The HyShot program currently consists of the following tests:
*HyShot 1 - UQ 2-D scramjet. Failed launch due to rocket fin puncture by a rock on the landing pad.
*HyShot 2 - UQ 2-D scramjet. Successful, July 30, 2002
*HyShot 3-7 - NASA tests. Cancelled after announcement of manned Mars mission.Fact|date=September 2007
*HyShot 8 (Now known as HyShot III) - QinetiQ 4-chamber scramjet. Successful, March 25, 2006. [http://www.uq.edu.au/news/index.html?article=9258]
*HyShot 9 (Now known as HyShot IV) - JAXA launch of UQ 2D scramjet with JAXA hypermixer. Planned, March 28, 2006.
*HyShot 10 - DSTO scramjet

Sponsorship for the HyShot Flight Program was obtained from, The University of Queensland, Astrotech Space Operations, Defence Evaluation and Research Agency (DERA (now Qinetiq), UK), National Aeronautics and Space Agency (NASA, USA), Defence, Science and Technology Organisation (DSTO, Australia), Dept. of Defence (Australia), Dept. of Industry Science and Resources (Australia), The German Aerospace Centre (DLR, Germany), Seoul National University (Korea), The Australian Research Council, Australian Space Research Institute (ASRI), Alesi Technologies (Australia), National Aerospace Laboratories (NAL, Japan), NQEA (Australia), Australian Research and Development Unit (ARDU, Australia), the Air Force Office of Scientific Research (AFOSR, USA) and Luxfer, Australia.

Hyper-X

The most advanced US hypersonics program is the US $250 million NASA Langley Hyper-X X-43A effort, which flew small test vehicles to demonstrate hydrogen-fueled scramjet engines. NASA is working with contractors Boeing, Microcraft, and the General Applied Science Laboratory (GASL) on the project.

NASA's Hyper-X program is the successor to the National Aerospace Plane (NASP) program which was cancelled in November 1994. This program involves flight testing through the construction of the X-43 vehicles. NASA first successfully flew its X-43A scramjet test vehicle on March 27, 2004 (an earlier test, on June 2, 2001 went out of control and had to be destroyed). Unlike the University of Queensland's vehicle, it took a horizontal trajectory. After it separated from its mother craft and booster, it briefly achieved a speed of 5,000 miles per hour (8,000 km/h), the equivalent of Mach 7, easily breaking the previous speed record for level flight of an air-breathing vehicle. Its engines ran for eleven seconds, and in that time it covered a distance of 15 miles (24 km). The "Guinness Book of Records" certified the X-43A's flight as the current Aircraft Speed Record holder on 30 August 2004. The third X-43 flight set a new speed record of 6,600 mph (10,620 km/h), nearly Mach 10 on 16 November 2004. It was boosted by a modified Pegasus rocket which was launched from a Boeing B-52 at 13,157 meters (43,166 ft). After a free flight where the scramjet operated for about ten seconds the craft made a planned crash into the Pacific ocean off the coast of southern California. The X-43A craft were designed to crash into the ocean without recovery. Duct geometry and performance of the X-43 are classified.

The NASA Langley, Marshall, and Glenn Centers are now all heavily engaged in hypersonic propulsion studies. The Glenn Center is taking leadership on a Mach 4 turbine engine of interest to the USAF. As for the X-43A Hyper-X, three follow-on projects are now under consideration:

Integrated Systems Test of an Air-Breathing Rocket

X-43B: A scaled-up version of the X-43A, to be powered by the Integrated Systems Test of an Air-Breathing Rocket (ISTAR) engine. ISTAR will use a hydrocarbon-based liquid-rocket mode for initial boost, a ramjet mode for speeds above Mach 2.5, and a scramjet mode for speeds above Mach 5 to take it to maximum speeds of at least Mach 7. A version intended for space launch could then return to rocket mode for final boost into space. ISTAR is based on a proprietary Aerojet design called a "strutjet", which is currently undergoing wind-tunnel testing. NASA's Marshall Space Propulsion Center has introduced an Integrated Systems Test of the Air-Breathing Rocket (ISTAR) program, prompting Pratt & Whitney, Aerojet, and Rocketdyne to join forces for development.

HyTECH

X-43C: NASA is in discussions with the Air Force on development of a variant of the X-43A that would use the HyTECH hydrocarbon-fueled scramjet engine.The US Air Force and Pratt and Whitney have cooperated on the Hypersonic Technology (HyTECH) scramjet engine, which has now been demonstrated in a wind-tunnel environment.

While most scramjet designs to date have used hydrogen fuel, HyTech runs on conventional kerosene-type hydrocarbon fuels, which are much more practical for support of operational vehicles. A full-scale engine is now being built, which will use its own fuel for cooling. Using fuel for engine cooling is nothing new, but the cooling system will also act as a chemical reactor, breaking long-chain hydrocarbons down into short-chain hydrocarbons that burn more rapidly.

Hyper-X Mach 15

X-43D: A version of the X-43A with a hydrogen-powered scramjet engine with a maximum speed of Mach 15.

FASTT

On December 10, 2005 Alliant Techsystems (ATK) [http://www.atk.com] successfully flight tested an air-breathing, liquid JP-10 (hydrocarbon) fuelled scramjet powered free-flight vehicle from NASA Wallops Flight Facility, Wallops Island, Virginia. The flight test was conducted under the Defense Advanced Research Projects Agency (DARPA)/ Office of Naval Research (ONR) Freeflight Atmospheric Scramjet Test Technique (FASTT) [http://www.atk.com/Customer_Solutions_MissionSystems/cs_ms_w_hs_fastt.asp] project. This latest flight was a culmination of a three year, three-flight program to successfully demonstrate the feasibility of using ground-launched sounding rockets as a low-cost approach to hypersonic flight testing, and represents the world’s first flight test of an air-breathing, scramjet powered vehicle using hydrocarbon fuel.

Begun in late 2002, the FASTT project entailed the design and fabrication of three flight vehicles and a ground test engine rig to undergo wind tunnel testing. The first and second payloads were dubbed surrogate payload vehicles and matched closely the scramjet flight article, but lacked the internal flowpath and fuel system. They were designed as test rounds to validate vehicle subsystems, such as booster stack combination performance, fin sets, payload deployment mechanism, telemetry and trackability, and inlet shroud, before flight testing the more complicated scramjet flowpath, which was to undergo proof-of-concept testing in a wind tunnel prior to flight testing.

The first surrogate vehicle, SPV1, was launched aboard an un-guided Terrier/Improved Orion two stage solid rocket motor stack from Wallops Island on October 18, 2003, approximately 12 months after program initiation. This had exact outer mold-lines to the eventual shrouded scramjet payload and contained full onboard instrumentation and telemetry suites. The vehicle was boosted to approximately convert|4600|ft/s|m/s|abbr=on and convert|52000|ft|m|abbr=on altitude, where it was deployed to free-flight, deployed its shroud at high dynamic pressure, and flew an un-powered trajectory to splashdown. All on-board subsystems worked flawlessly. The boost stage however inserted the payload at lower than desired flight speed, altitude, and flight path angle. The second surrogate vehicle, SPV2 was launched aboard the identical booster stack from Wallops Island on April 16, 2004, approximately six months after the first launch. After making slight trajectory corrections to account for launch rail effects, higher than anticipated drag, and actual booster performance, the payload was inserted nominally above convert|5200|ft/s|m/s|abbr=on and convert|61000|ft|m|abbr=on altitude. The full compliment of subsystems were again proven out in flight on this successful flight test. The results of these two flight tests are summarized in a technical paper AIAA-2005-3297, presented at the 13th International Space Planes and Hypersonics Systems and Technologies Conference (see [http://www.aiaa.org] )in Capua, Italy. The ground test engine hardware was fabricated over 18 months and underwent a four month engine validation testing program in the ATK GASL freejet wind tunnel complex Leg 6, located in Ronkonkoma, New York. Ignition, fuel throttling, and engine operation were wrung out over a range of expected flight conditions. After a delay of 2 months to modify flight hardware based on ground test findings, the first powered vehicle, FFV1, was launched without incident, propelled to speeds of convert|5300|ft/s|m/s|abbr=on at convert|63000|ft|m|abbr=on altitude, roughly Mach 5.5. Over 140 inlet, combustor, and vehicle outer mold line pressure, temperatures, and vehicle accelerations as well as fuel pressure, timing feedback, and power systems monitoring were recorded. The vehicle executed the prescribed test sequences flawlessly for 15 seconds, before continuing on to splashdown into the Atlantic Ocean. Further details can be found in the technical paper AIAA-2006-8119, presented at the 14th International Space Planes and Hypersonics Systems and Technologies Conference, in Canberra, Australia.

Alliant Techsystems Inc. (ATK) GASL Division led the contractor team for the FASTT project, developed and integrated the scramjet vehicle, and acted as mission managers for the three flights. Launch vehicle integration and processing was performed by Rocket Support Services (formerly DTI Associates), Glen Burnie, MD; the flight shroud was developed by Systima Technologies, Inc., Bothell, WA.; electrical systems, telemetry and instrumentation was handled by the NASA Sounding Rocket Office Contract (NSROC); flight test support was provided by the NASA Wallops Flight Facility; and technical support was provided by the Johns Hopkins Applied Physics Laboratory, Baltimore, MD. GASL previously built and integrated the engine flowpaths and fuel systems for the three X-43A flight vehicles, working closely with air framer and systems integrator Boeing, NASA Langley, and NASA Dryden on the successful Hyper-X Program.

US Military

To coordinate hypersonic technology development, the various factions interested in hypersonic research have formed two integrated product teams (IPTs): one to consolidate Army, Air Force, and Navy hypersonic weapons research, the other to consolidate Air Force and NASA space transportation and hypersonic aircraft work. Current funding levels are relatively low, no more than US $85 million per year in total, but are expected to rise.

Promethee

Several scramjet designs are now under investigation with Russian assistance. One of these options or a combination of them will be selected by ONERA, the French aerospace research agency, with the EADS conglomerate providing technical backup. The notional immediate goal of the study is to produce a hypersonic air-to-surface missile named "Promethee", which would be about 6 meters (20 ft) long and weigh 1,700 kilograms (3,750 lb).

Russia

First working scramjet "GLL Holod" in world flies on 28 November, 1991 reaching speed mach 5.8.Fact|date=June 2007However, the collapse of Soviet Union stopped the funding of the project.

After NASA's NASP program was cut, American scientists began to look at adopting available Russian technology as a less expensive alternative to developing hypersonic flight. On November 17, 1992, Russian scientists with some additional French support successfully launched a scramjet engine "Holod" in Kazakhstanfn|6. From 1994 to 1998 NASA worked with the Russian Central Institute of Aviation Motors (CIAM) to test a dual-mode scramjet engine and transfer technology and experience to the West. Four tests took place, reaching Mach numbers of 5.5, 5.35, 5.8, and 6.5. The final test took place aboard a modified SA-5 surface to air missile launched from the Sary Shagan test range in the Republic of Kazakhstan on 12 February 1998. According to CIAM telemetry data, first ignition of the scramjet was unsuccessful, but after 10 seconds the engine was started and the experimental system flew 77s with good performance, up until the planned SA-5 missile self-destruction (according to NASA, no net thrust was achieved).

Some sources in the Russian military have said that a hypersonic (10-15M) maneuverable ICBM warhead was tested.

The new "GLL Igla" system is expected to fly in 2009.

GASL projectile

At a test facility at Arnold Air Force Base in the U.S. state of Tennessee, GASL fired a projectile equipped with a hydrocarbon-powered scramjet engine from a large gun. On July 26, 2001, the four inch (100 mm) wide projectile covered a distance of 260 feet (79 m) in 30 milliseconds (roughly 5,900 mph or 9,500 km/h). The projectile is supposedly a model for a missile design. Many do not consider this to be a scramjet "flight," as the test took place near ground level. However, the test environment was described as being very realistic.

FALCON

The final target of this program is a hypersonic vehicle that will be using scramjet technology.

India

The Thiruvananthapuram-based Vikram Sarabhai Space Centre (VSSC) of the Indian Space Research Organisation (ISRO) had designed and ground tested a scramjet in 2005. A press release stated that stable supersonic combustion was demonstrated in ground testing for nearly seven seconds with an inlet Mach number of six. A flight test of a full engine (intake, combustion chamber and nozzle) was planned for 2008. The experiment is to be a suborbital ballistic trajectory using a two-stage RH-560 sounding rocket. This method, also used by the HyShot program, is much cheaper, but has shorter test times than the horizontal trajectory used in the Hyper-X program.

See also

*Boeing X-51
*Jet engine
*Ramjet
*Single-stage to orbit
*Skylon and the earlier project HOTOL

References

Notes

*fnb|1Thompson, Milton O. “At the Edge of Space”. Smithsonian Institution, Washington. 1992.
*fnb|2 Paull, A., Stalker, R.J., Mee, D.J. "Experiments on supersonic combustion ramjet propulsion in a shock tunnel", JFM 296: 156-183, 1995.
*fnb|3 Kors, D.L. “Design considerations for combined air breathing-rocket propulsion systems.”, AIAA Paper No. 90-5216, 1990.
*fnb|4 Varvill, R., Bond, A. " [http://www.reactionengines.co.uk/downloads/JBIS_v56_108-117.pdf A Comparison of Propulsion Concepts for SSTO Reuseable Launchers] ", JBIS, Vol 56, pp 108–117, 2003. Figure 8.
*fnb|5 Varvill, R., Bond, A. " [http://www.reactionengines.co.uk/downloads/JBIS_v56_108-117.pdf A Comparison of Propulsion Concepts for SSTO Reuseable Launchers] ", JBIS, Vol 56, pp 108–117, 2003. Figure 7.
*fnb|6 Voland, R.T., Auslender, A.H., Smart, M.K., Roudakov, A.S., Semenov, V.L., Kopchenov, V. "CIAM/NASA Mach 6.5 scramjet flight and ground test", AIAA-99-4848.
*fnb|7 Oldenborg R. et al "Hypersonic Combustion Kinetics: Status Report of the Rate Constant Committee, NASP High-Speed Propulsion Technology Team" NASP Technical Memorandum 1107, May 1990.
*fnb|8 Billig, FS "SCRAM-A Supersonic Combustion Ramjet Missile", AIAA paper 93-2329, 1993.
* [http://www.mech.uq.edu.au/hyper/hyshot/ HyShot -University Of Queensland] "HyShot Leaders in Scramjet Technology"
* [http://news.bbc.co.uk/2/hi/science/nature/4832254.stm Latest results] from the 24 March 2006 QinetiQ HyShot launch.
* [http://www.netwrx1.com/skunk-works/v02.n027 French Support Russian SCRAMJET Tests.]
* [http://www.americanscientist.org/template/AssetDetail?assetid=14779#17708 A Burning Question.] "American Scientist".
* [http://www.spacedaily.com/news/scramjet-01a.html Hypersonic Scramjet Projectile Flys in Missile Test.] "SpaceDaily".
* [http://hapb-www.larc.nasa.gov/Public/Projects/national_hypersonics_plan.html NASA website for National Hypersonics Plan]
* [http://www.nasa.gov/missions/research/x43-main.html NASA's X-43A]
*http://www.uq.edu.au/hypersonics/index.html?page=19501 University of Queensland Centre for Hypersonics]

External links

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* [http://news.bbc.co.uk/1/hi/sci/tech/4832254.stm BBC: Scramjet]