Air Force Plans Flight Tests Of Hypersonic Vehicle

A joint U.S. Air Force and Defense Advanced Research Projects Agency (DARPA) project is moving speedily along--intended to fly to Mach 20, plus some.

The Falcon Hypersonic Technology Vehicle program is exploring high-speed air vehicles designed for rapid, around-the-world reach. Project goals are to develop hypersonic technology for a glided or powered system, as well as advance small, low cost, and responsive launch vehicles.

A Falcon Hypersonic Test Vehicle-1 (HTV-1) is now on the books for a less than one-hour flight in September 2007. Attaining Mach 19 (19 times the speed of sound), the glided air vehicle will briefly exit the Earth's atmosphere and reenter flying between 19 and 28 miles above the Earth's surface. This inaugural voyage of HTV-1 would end in the Pacific Ocean.

The Falcon HTV program is geared to showcase the ability of a craft to attain hypersonic speeds - ranging from 6,000 to 15,000 miles per hour (Mach 9 to Mach 22), and reach altitudes between 100,000 to 150,000 feet. To do so will necessitate an airframe structure designed to survive intense heat and pressure.

There are other partners participating in the demonstration program: NASA, the Space and Missile Systems Center, Sandia National Laboratories and the Air Force Research Laboratory's (AFRL) Air Vehicles and Space Vehicles Directorates.

Critical technologies

Work is now underway to build the Falcon HTV-1's flight hardware components. The test vehicle will be integrated at a Lockheed Martin facility in Valley Forge , Pennsylvania.

AFRL's Space Vehicles directorate, located at Kirtland Air Force Base in New Mexico, is specifically focusing on technologies for the glided system and issued a January 25 background release on the hypersonic work. Technologists there are helping to develop a thermal protection system for the HTV structure to withstand 3,000-degree temperatures and extreme exterior pressures - 25 times those experienced by NASA's space shuttle orbiter.

Other critical technology to be investigated in the Falcon HTV work includes an all carbon aeroshell. This outer casing must tolerate crushing pressures and intense heat. To keep the vehicle interior cool, an advanced multi-layer insulation is being fabricated for long duration flights. In addition, researchers are designing tools for enhanced HTV navigation and maneuverability.

Trio of flights

A second glided flight is slated for 2008 or 2009. That HTV-2 test would feature a different structural design, enhanced controllability, and higher risk/performance factors during its high-speed journey. Like its predecessor, the system will reach Mach 22 speed, and then finish its one-hour plus mission in the Pacific Ocean.

Also scheduled is a third and final flight of a Falcon HTV. That test shot is planned for 2009 and will be a departure from the previous two demonstrations.

This time the reusable hypersonic glider will lift off from NASA's Wallops Flight Facility, Wallops Island, Virginia.

Screaming out of the area, the HTV-3 would be recovered in the Atlantic Ocean an hour later. In addition, the HTV-3--flying at a maximum Mach 10 speed--would achieve high aerodynamic efficiency and validate external heat barrier panels that will be reusable.

Affordable, adaptable, and responsive

"We have made great progress and are on track for the first glided hypersonic test vehicle flight in 2007," said Russ Partch, Falcon HTV-1 project manager in the AFRL release. "It will enable a revolutionary capability to quickly respond to events anywhere around the world."

Partch added that the HTVs will prove technologies for global reach vehicles that can get a payload to the area of interest quickly in support of the joint warfighter.

The results of the trio of HTV experimental flights are viewed as having a significant impact in the development of future affordable, adaptable, and responsive military delivery platforms and launch systems.

According to AFRL, the Falcon HTV program is expected--during the next three to four years--to tackle challenges related to hypersonic flight by in-flight validation of technologies while demonstrating operationally responsive space lift.