What is hypersonic flight?
Hypersonic Flight Experiment or HEX was the first test flight in the RLV Technology Demonstration Programme of the Indian Space Research Organisation (ISRO). The demonstration trials will pave the way for a two-stage-to-orbit (TSTO) fully re-usable launch vehicle. HEX was launched on 23 May, 2016.

Objectives

HEX was the first test flight of a reusable launch vehicle developed by India. The test flight objectives included:
• Validating the aerodynamic design characteristics during hypersonic flight
• Characterize induced loads during the hypersonic descent through the atmosphere
• Assess the performance of the carbon fibre used in construction of the nose of the vehicle
• Demonstrate first stage separation sequencing

Launch and flight

The Hypersonic Flight Experiment, or HEX, was the first test-flight in the RLV Technology Demonstration Programme. The RLV-TD vehicle was launched from the first launchpad of Satish Dhawan Space Centre on 23 May 2016 at 7:00 AM local time, onboard an HS9 rocket booster. After a successful lift that lasted 91.1 seconds to a height of about 56 km, the RLV-TD separated from the 9-ton HS9 booster and further ascended to a height of about 65 km. The RLV-TD then began its descent at about Mach 5 (five times the speed of sound). The vehicle’s navigation, guidance and control systems accurately steered the vehicle during this phase for a controlled splashdown down to the defined landing spot over the Bay of Bengal, at a distance of about 450 km from Sriharikota, thereby fulfilling its mission objectives.


The vehicle was tracked during its flight from ground stations at Sriharikota and a shipborne terminal. The total flight duration from launch to splashdown lasted about 770 seconds. The unit was not planned to be recovered. ISRO plans to construct an airstrip greater than 4 km long in Sriharikota Island in the “near future”. Critical technologies such as autonomous navigation, guidance & control, reusable thermal protection system, and descent mission management were validated in this flight.

How Hypersonic Planes Work?

NASA’s experimental space plane, the X-43A, set a new speed record for aircraft on November 16, 2004. In the unmanned test flight, the plane reached Mach 10 — 10 times the speed of sound, or about 6,600 miles (10,600 kilometers) per hour. This flight broke the previous speed record of Mach 7, set in March 2004 by the X-43A in a previous test flight. What sets the X-43A apart from other rocket-powered aircraft is that it is powered by a scramjet engine. Instead of using onboard oxygen to combust the hydrogen fuel, the scramjet scoops up oxygen as it travels through the atmosphere. By eliminating the need for onboard oxygen, cutting the weight of the spacecraft, the X-43A could lead to cheaper Earth-to-orbit space travel. The futuristic X-43A prototype looks like a flying surfboard. It’s thin, has a wingspan of 5 feet (1.5 m), measures 12 ft (3.7 m) long and 2 ft (0.61 m) thick and weighs 2,800 pounds (1,270 kg). But the most unique feature of the X-43A is its engine.
The best way to understand an X-43A’s air-breathing engine is to first look at a conventional rocket engine. A typical rocket engine is propelled by the combustion created when a liquid oxidizer and a hydrogen fuel are burned in a combustion chamber. These gases create a high-pressure, high-velocity stream of hot gases. These gases flow through a nozzle that further accelerates them to speeds of 5,000 to 10,000 mph (8,000 to 16,000 kph) and provides thrust.

The Hypersonic Age is near!

The world is at the start of a renaissance in supersonic and hypersonic flight that will transform aviation, but the effort will need steady commitment and funding if the United States wants to lead the way, congressional leaders and industry officials said at a forum late last month.
“What’s exciting about aerospace today is that we are in a point here where suddenly, things are happening all across the board in areas that just haven’t been happening for quite a while,” said former U.S. Air Force Maj. Gen. Curtis M. Bedke.
“There was a period where engine technology had just sort of stagnated a point where all materials technology was going along at about the same pace,” Bedke added. “There just wasn’t much happening. But suddenly, in all sorts of areas that apply to aerospace, things are happening.”
Bedke was one of five panelists to speak Oct. 27 at the Forum on American Aeronautics here at the Mojave Air and Space Port. Sponsored by the House Committee on Science, Space, and Technology, the forum was hosted by committee chairman Lamar Smith, R-Texas, and member Steve Knight, R-Calif. Bedke, Smith and Knight were joined by David McBride, director of NASA’s Armstrong Flight Research Center in California, and Craig Johnson, director of business strategy and development for Lockheed Martin’s Skunk Works. Former Mojave Air and Space Port CEO Stu Witt moderated.


Knight has taken the lead on the House Science Committee in getting NASA’s aeronautical program to focus on a new set of experimental aircraft. He said his passion for these programs isn’t just about improving American aviation it’s personal.
“In 1967 was the last time we went hypersonic in an airplane,” Knight said, referring to an X-15 flight piloted by his late father, William J. “Pete” Knight. That flight reached Mach 6.7 — 6.7 times the speed of sound a record for piloted aircraft that still stands nearly 50 years later. (Hypersonic flight is generally defined as anything that reaches Mach 5 or greater. “Supersonic” refers to any flight that exceeds Mach 1.)
Since that time, the U.S. has conducted two unpiloted hypersonic research programs, X-51 and X-43. However, there was no continuity in the work, Knight said, “We collected an awful lot of data,” he said. “But what I would like to see is that we can move that data into something, whether we are going to move into an aircraft that we’re going to put people into or we’re going to use it for some other program. We’ve got to have that continuity and move forward.”

THE WARP SPEED OF TODAY

Private companies in China and America are achieving hypersonic speed in aircraft speeds categorized as those which exceed five on the mach scale, which equates to 3,835 miles per hour or above. At this speed, an aircraft could travel the circumference of the Earth in approximately 6 and a half hours. We could see this speed attained and made commonplace within the next few years, with estimates stretching from 2020 to 2030. Alan Bond, a co-founder of Reaction Engines, said that this could be “a revolution in transportation equivalent to the jet engine.”
It is only now that we really have the technology required to overcome the extreme heat (surface temperatures exceed 1,000 degrees Celsius) and changes in air that occur at these ludicrous speeds. as well as developing ways to introduce them into common usage by tackling factors like the deafening boom caused by breaking the sound barrier. Among the most prominent companies working on this is Lockheed Martin, whose SR-72 will reportedly be used to carry out surveillance missions as a successor to the SR-71 blackbird. The company announced earlier this month that it would begin production.
Additionally, the Chinese Aerospace Science and Industry Corporation has finished a successful technology demonstration for their Teng Yun plane, which launches in two stages. The first uses a TRCC engine to propel it to altitudes of 29 to 40 kilometers, after which it detaches and leaves a rocket propelled space plane that can fly as far as the moon. Skylon is a British plane that pursues similar ambitions. At the more commercial end of the spectrum is Boeing’s X-51A, which undertook a 240 second successful flight over the Pacific last year. Dennis Muilenburg, the company’s CEO told CNBC that “I think in the next decade or two you’re going to see them (hypersonic planes) become a reality.”

THE FUTURE OF FLIGHT

This technology has particular consequences in three sectors: commercial travel, the military, and spaceflight. Commercially, hypersonic planes have the potential to rapidly decrease flight times, and therefore decrease the frustration, weariness, and inconvenience that long-haul flights can cause. While companies are still calculating whether the cost of such an undertaking is viable, Tom Enders, the CEO of Airbus, optimistically stated that we have “ever more fuel efficient aircraft,” which could indicate that the cost of these flights would not be too much more expensive than today’s commercial flights. This technology could also change the nature of military flight fundamentally.

Brad Leland, a Lockheed engineer, told Reuters that “your adversaries cannot hide or move their critical assets. They will be found. That becomes a game-changer.” The principles applied to the aircraft could also be used to develop new missiles. Theis principle in both cases is to opt for speed over stealth: becoming fast enough that the enemy prevent the attack or surveillance mission due to the speed of the aircraft or missile. Perhaps most promisingly, however, are the potential applications for spaceflight. While there has been a huge amount of coverage concerning reusable rockets recently, using space planes are an alternative could potentially be more viable. At the very least, the development of the planes of the future will add another competitor to the commercial space race, and this competition will lead to remarkable innovation.ow will it change, how we travel?

Hypersonic Flight Is Coming: Will the US Lead the Way?

The world is at the start of a renaissance in supersonic and hypersonic flight that will transform aviation, but the effort will need steady commitment and funding if the United States wants to lead the way, congressional leaders and industry officials said at a forum late last month. “What’s exciting about aerospace today is that we are in a point here where suddenly, things are happening all across the board in areas that just haven’t been happening for quite a while,” said former U.S. Air Force Maj. Gen. Curtis M. Bedke. “There was a period where engine technology had just sort of stagnated a point where all materials technology was going along at about the same pace,” Bedke added. “There just wasn’t much happening. But suddenly, in all sorts of areas that apply to aerospace, things are happening.”
Bedke was one of five panelists to speak Oct. 27 at the Forum on American Aeronautics here at the Mojave Air and Space Port. Sponsored by the House Committee on Science, Space, and Technology, the forum was hosted by committee chairman Lamar Smith, R-Texas, and member Steve Knight, R-Calif. Bedke, Smith and Knight were joined by David McBride, director of NASA’s Armstrong Flight Research Center in California, and Craig Johnson, director of business strategy and development for Lockheed Martin’s Skunk Works. Former Mojave Air and Space Port CEO Stu Witt moderated.
“In 1967 was the last time we went hypersonic in an airplane,” Knight said, referring to an X-15 flight piloted by his late father, William J. “Pete” Knight. That flight reached Mach 6.7 — 6.7 times the speed of sound a record for piloted aircraft that still stands nearly 50 years later. (Hypersonic flight is generally defined as anything that reaches Mach 5 or greater. “Supersonic” refers to any flight that exceeds Mach 1.) Since that time, the U.S. has conducted two unpiloted hypersonic research programs, X-51 and X-43. However, there was no continuity in the work, Knight said.
“We collected an awful lot of data,” he said. “But what I would like to see is that we can move that data into something, whether we are going to move into an aircraft that we’re going to put people into or we’re going to use it for some other program. We’ve got to have that continuity and move forward.”
Knight noted that it still takes the same 4.5 hours or so to fly from New York to Los Angeles today as it did 30 years ago. Supersonic aircraft flights over land have been banned for decades because of the sonic booms they produce. No supersonic passenger planes have been in operation since the retirement of the Concorde in 2003.


NASA wants to change that. In February, the space agency awarded a contract to Lockheed Martin for the design of an experimental plane to test technologies that can significantly reduce the sonic booms caused by aircraft. If the program is successful, the ban on overland supersonic flights could be lifted.
“We’re poised on the brink of a new era in air transportation,” McBride said. “We do need to go faster. There is a market for supersonic flight over land in an efficient manner that can fly without being an annoyance to everyone on the ground.” NASA also is exploring ways to improve the efficiency and reduce the environmental impacts of subsonic aircraft. Engineers are experimenting with blended wings and other innovations. Smith admitted that the difficulty that Congress and the president have experienced in passing budgets has caused problems in sustaining research.
“None of that is conducive to good work getting done in an efficient way,” Smith said. “And we can do better. We need to get to the point where continuity actually lasts beyond just one administration, much less beyond tomorrow. And we’re with you on that.” Bedke said there is no time to waste in moving these programs forward.
“It is inevitable that hypersonic technologies are going to happen,” he said. “It is not inevitable that we are going to be the country to do it first. But we can be the country to do it first, but we’re going to have to put our minds to it, and we’re going to have to stop the history of fits and starts, of throwing money at a big program, achieving a wild success, and then having no follow-up. Or throwing a lot of money at too big a program, taking too giant a bite, failing miserably and then deciding hypersonics isn’t going anywhere. Neither of those must be allowed to happen in the coming years.”

Sydney to London in an hour? The future of hypersonic air travel

HTV-2 glides at Mach 20 (~20,000km/h) – an incredibly high speed to travel within the Earth’s atmosphere. If you could sustain this speed for long enough you could go from Sydney to London in around 50 minutes. But travel at these speeds is not new. Ever since the dawn of the space age astronauts have been propelled to considerably faster speeds in order to enter earth orbit. What’s different about the HTV-2 is that it “flies” at these speeds within Earth’s atmosphere. At altitudes below about 50 kilometres this generates incredible friction.
The heat from atmospheric friction can lead to the melting of all known materials if the heat cannot be dissipated. Conventional aluminium can be used for aircraft such as the now-retired Concorde that fly at speeds below Mach 2. The American SR-71 Blackbird, which flew at speeds greater than Mach 3, was made of titanium, an extremely light and strong metal that can maintain its strength up to 450 degrees Celsius. Consequently, the HTV-2 encountered heating rates that were almost 300 times greater than the SR-71 when flying at the same altitude. To survive such temperatures, the HTV-2 uses a type of material known as Ceramic Matrix Composites (CMC) that can maintain their strength up to 2,000 degrees Celsius or more. There are many things that can go wrong on an experimental flight like this. At this stage it’s not known if the incredibly high heating of the HTV-2’s outer skin was to blame for the failure, or if something else was at play.
While the goals of the HTV-2 are impressive, the craft is a simple glider with no propulsion system. Its range is therefore limited by aerodynamic efficiency, in particular its lift to drag ratio. The real future of hypersonic flight in the atmosphere is the design of hypersonic air-breathing engines called Supersonic Combustion Ramjets (Scramjets). Australia is at the forefront of scramjet technology through the research and flight testing being done within the Centre for Hypersonics at the University of Queensland .A computer model of an aircraft being designed by the University of Queensland’s HyShot group.

Scramjets work in the same way as a conventional jet engine, by increasing the velocity (and therefore momentum) of air passing through it by burning fuel. As you might remember from high school science lessons, Sir Issac Newton showed that a change in momentum produces a force. In an air-breathing engine the change in momentum of the air creates thrust. At hypersonic speed the engine thrust must overcome the drag generated by pushing the air out of the way at tremendous speeds. In this way, scramjets are fighting an uphill battle.
Current research, authored by myself and others, shows scramjets may be able to operate up to Mach 12 or even Mach 14. If this can be proved in flight, then travel around the globe in a matter of hours is possible. Scramjets can also be used to put satellites into space more efficiently than rockets. The same high temperature materials pioneered for use in the HTV-2 are expected to be applied to hypersonic vehicles propelled by scramjets. While aircraft such as the HTV-2 or those being developed at UQ are still in the experimental phase, the ultimate goal is to see hypersonic aircraft enter the commercial market. The first experience that you or I might have of hypersonic flight could come as an extension of the space adventure flights to be offered by Virgin Galactic.

Patents related to the technology

1. Hypersonic flight vehicle
US 5082206 A: A hypersonic inlet and a hypersonic engine and flight vehicle having such an inlet. The three-dimensionally-swept inlet has an upper member with a caret-shaped lower surface portion producing a two-dimensional wedge flow below such lower surface portion. The inlet also has a lower member having two inverted and transposed semi-caret-shaped upper surface portions producing a two-dimensional wedge flow above such upper surface portions. An inlet aft portion connects together the upper and lower members and has an orifice defining the engine inlet throat which at least partially receives the two-dimensional flows.

2. Airbus patented new designs for a jet that could fly from London to New York in 1 hour: US0344158 A1
The airplane is described by the company as “a space aircraft capable of taking off from the ground in the usual manner, reaching an altitude of at least a hundred kilometres, flying at a transsonic or even supersonic speed, and then landing in the usual manner of an aircraft.” The plane would have a huge rocket engine at the back of the body, with two turbojet engines on either side of it. The turbojets would fly the plane up to a certain altitude, before the rocket engine ignites, sending the plane vertically upwards to its final altitude. At first ignition, the rocket engine would make a huge supersonic boom, creating enormous drag on the aircraft, which Airbus says it would counter this with anti-drag flaps. When it released the original designs back in July, Airbus said that the hypersonic jet could have both civilian and military applications. In civilian trim, the craft could serve as private jet or as an airliner with room for 20 passengers. When used by the military, the jet could serve as transport for soldiers or as a reconnaissance plane.