Scramjet-powered X-43A Breaks Speed Record

Released on Wednesday, November 17, 2004

Under NASA's Hyper-X research vehicle program, the X-43A vehicle powered by an air-breathing Supersonic Combustion Ramjet or Scramjet engine flew close to Mach 10 (7,200 miles per hour or 11,500 kph) for over 10 seconds on November 16, 2004. Mach 10 means ten times de speed of sound. Flight endurance must be kept short because air rubbing at high speeds involves intense heat generation which can melt X-43's airframe.

The flight took place in restricted airspace over the Pacific Ocean northwest of Los Angeles at an altitude of approximately 110,000 feet or 33,500 meters. This flight was the last in a series of three unpiloted flight tests carried out under Hyper-X program. Hyper-X is aimed at studying air-breathing technology as an alternative to current rocket power for space access vehicles.

Supersonic Combustion Ramjets, Scramjets, promise more airplane-like operations for increased affordability, flexibility and safety in ultra-high speed flights within the atmosphere and for the first stage to Earth orbit. The Scramjet engines has no moving parts and compresses the air passing through it to ignite the fuel. These engines can be throttled back, reducing power output, allowing a scramjet-powered vehicle to fly more like an aircraft. Rocket engines produce full or near full power all the time, making extremely difficult to maneuver the vehicle.

The 12.3 feet (3.75 meters) long attached to a Pegasus booster was released over the Pacific coast from a modified B-52 heavyweight bomber at 40,000 feet of altitude after liftoff from Edwards Air Force Base, California. Pegasus booster rocket ignited accelerating to up to Mach 4 (see picture above). Then the scramjet-powered X-43A vehicle was engaged accelerating to Mach 10 at an altitude of 110,000 feet. Unlike rocket motors, air-breathing scramjet engines don't need oxygen tanks. NASA has predicted that future Scramjet-powered vehicles might travel as fast as Mach 15.

Promising air-breathing engines technology could lead to development of global strike aircraft (HCV), long range cruise missiles (HyFly), and ultra-fast commercial aircraft that could fly intercontinental routes, typically requiring 10 hours, in less than one hour.