How NASA’s X-43 Hypersonic Aircraft Almost Reached Mach 10 in Testing

X-43 was an advanced prototype that tested the feasibility of scramjet engines for hypersonic flight.
Nasa X-43

The experimental aircraft known as NASA X-43 was specially designed to evaluate the feasibility of hypersonic flights.

The experiment wasn’t entirely successful. But, the scramjet technology of the aircraft left such an impressive legacy that it is probably the key to achieving hypersonic speeds (5 times the speed of sound) in a safe and reliable way.

How powerful was the X-43?

X-43A by Public Domain.

The NASA X-43 was an unmanned experimental aircraft to test hypersonic flight technologies. It was an experimental aircraft funded by NASA as part of their Hyper-X program. The goal of the program was to develop technologies for hypersonic flight. 


The X-43 was launched from a B-52 bomber and then accelerated to supersonic speeds using a rocket booster. Once it reached Mach 3, the aircraft’s scramjet engine took over and propelled it to even higher speeds.

B-52 carries X-43A
B-52 carries X-43A by NASA/Tom Tschida. Public Domain.

It was so impressive that it set the world speed record for a jet-powered aircraft when it hit Mach 9.6, or almost 11,854.08 km/h or 7366 miles per hour on November 16, 2004.

The X-43 was designed to reach Mach 10, making it the fastest air-breathing vehicle ever built. Unfortunately, the aircraft never reached its full potential due to many technical difficulties.


One issue was that the engine wasn’t able to function correctly at high altitudes, which limited the aircraft’s range. In addition, the heat generated by friction at such high speeds caused premature engine failure.

As a result, the X-43 never lived up to its potential but reaching Mach 9.6 was an outstanding record anyway.

NASA’s X-43 legacy

B-52B with X43
B-52B with X43 by NASA. Public Domain.

At Mach 9.6, the NASA X-43 was traveling at nearly ten times the speed of sound, making a significant contribution to the development of hypersonic flight technologies. 


Actually, after this test, Scramjet technology was set to enable hypersonic flights.

In Scramjet technology, the jet engine uses air intakes to compress the air, which is then mixed with fuel and ignited in a combustion chamber. The hot gases that result from this process are then expelled through a nozzle, providing thrust that propels the aircraft forward. 

Scramjet engines are designed to overcome this problem by using supersonic airflow throughout the engine, meaning that they can operate at extremely high speeds. 


X-43A (Hyper - X) Mach 7 computational
X-43A (Hyper – X) Mach 7 computational by NASA. Public Domain.

Currently, scramjet technology is still in the early stages of development, but it has the potential to revolutionize hypersonic flight soon.

SR-72: the next hypersonic aircraft to change military aviation

The SR-72 is an unmanned aerospace vehicle under development by Lockheed Martin. Announced in 2013, it is designed to succeed the SR-71 Blackbird, which was retired in 1998 as the fastest manned aircraft ever built. 

And with the technologies researched in the X-43, it will be finally possible to build a hypersonic aircraft like the SR-72. It is expected to fly at Mach 6. This would make it the fastest aircraft ever built.


However, the SR-72 is still in the early stages of development, and it is unclear if it will ever reach production. If it does, it could revolutionize military aviation and finally demonstrate the importance of the Nasa X-43 as a hypersonic prototype. 

NASA’s X-43 set a speed record that will be hard to beat

This aircraft faced many logistical and engineering issues that made its widespread use almost impossible. However, this technology advanced, and today it is much more feasible than ever before.

That’s why the USAF’s following developments, such as the son of SR-71 Blackbird, the SR-72, or a sixth-generation fighter jet, could already implement scramjet technology to ultimately achieve hypersonic flight consistently.


Featured image credit: Nasa X-43 by NASA.Public Domain.

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