DARPA’s Falcon Hypersonic Technology Vehicle 2 (HTV-2) hit approximately Mach 20 — about 13,000 miles per hour or 3.6 miles per second. DARPA claimed the Falcon could fly from New York City to Los Angeles in under 12 minutes. Nobody has built anything faster than DARPA’s Falcon HTV-2. The Falcon HTV-2 was an unmanned launch vehicle. DARPA aimed to have the hypersonic craft travel anywhere around the globe in under an hour.
HTV-2 Was a Mach 20 Miracle
X-15 Harry J. Kazianis National Security Journal Photo.
X-15 Long Shot and Engine Photo. Image Credit: National Security Journal.
Give a hat tip to those egg heads at DARPA. Don’t get the wrong idea, I say that affectionately because the scientists there are intelligent beyond belief. The highly effective U.S. government research and development agency has a long record of creating the world’s most whiz-bang defense projects. The think tank outdid itself years ago with a project that will knock your socks off.
Yes, That Is 13,000 Miles Per Hour
DARPA hatched a technology demonstrator capable of traveling up to MACH 20. That’s around 13,000 miles per hour. It was called the Falcon Hypersonic Technology Vehicle 2 (HTV-2) program. This provided the innovations and scientific discovery that framed the Department of Defense’s Conventional Prompt Global Strike programs.
DARPA modeled and simulated the Falcon program for years. There was extensive wind-tunnel testing and even two flight tests. DARPA aimed to have the hypersonic craft travel anywhere around the globe in under an hour.
‘She’s Got a Ticket to Ride’ From New York to Los Angeles
The Falcon HTV-2 was an unmanned launch vehicle. DARPA claimed that the Falcon could make it from New York City to Los Angeles in below 12 minutes. DARPA also called the HTV-2 a “data truck” that vacuumed up telemetry and other data during its flight. Falcon is an acronym that stands for “Force Application and Launch from Continental United States.”
X-43A Test Image. Image Credit: Creative Commons.
X-43A from NASA. Image Credit: Creative Commons.
X-43A NASA. Image Credit: NASA.
Setting the Standards for Hypersonic Flight
Falcon made its first flight in 2010 and stayed in the air, hoovering up data for only nine minutes. But during that time, it hit over MACH 17 for 139 seconds, DARPA revealed.
In a news release, DARPA announced that Falcon:
-“Deployed the largest number of sea, land, air, and space data collection assets in support of hypersonic flight test;
-Maintained Global Positioning System (GPS) signals while traveling 3.6 miles per second;
-Validated two-way communication with the vehicle.
-Verified effective use of the Reaction Control System (RCS).”
There Was Another Test
There was a second flight in 2011 that lasted about nine minutes. DARPA wanted to analyze “shock waves, boundary layer transition, mechanical stresses, and navigation” at MACH 20 speeds, according to FlyaJetFighter.
Good Reasons to Celebrate
This was an incredible feat of engineering. It is amazing that DARPA was thinking about ultra-fast hypersonic flight so long ago. This would have led to some very smart people high-fiving each other, even though the tests were short. But flying at 3.6 miles per second was something to be proud of.
The other interesting breakthrough was making the Falcon maneuverable in the air and the ability to collect flight data and other intelligence. The U.S. Air Force also worked with DARPA to deliver these rapid technology demonstrators. Falcon was not planned to be a functioning missile, but it paved the way for future weapons development. It is slightly disappointing that, even with this hypersonic flight so long ago, the United States could have been a more prominent global leader in plus-MACH-5 flight today.
How Did Falcon Do the Impossible?
FlyaJetFighter has an excellent description of how Falcon worked. “The HTV-2 is a hypersonic glider-type vehicle. It is based on a ‘boost-glide’ concept: a rocket provides the initial energy [the boost phase], then the vehicle separates and ‘glides’ without propulsion [the glide phase]. It is therefore neither a scramjet nor a ramjet aircraft. All of its performance comes from the energy supplied at the start, then from its ability to convert part of this energy into lift and distance, while surviving the heat and remaining controllable.”
We Are Talking Real Heat Generation
“Heat and remaining controllable” is the critical point of failure here. DARPA would need some extra brainpower to ensure that Falcon did not overheat (3,500 degrees Fahrenheit at the surface) and break up. The flight characteristics were unpredictable during the test flights. If this thing had changed trajectory, it could have been lost during the boost and glide phase.
DARPA and the Air Force thus had to struggle with controlling this force of nature. That’s one reason the flight tests were so short.
“The more the vehicle heats up, the more its properties change [rigidity, expansion, mechanical play]. The more its properties change, the more its aerodynamic model drifts. The more the model drifts, the more the autopilot makes decisions based on false assumptions. And at these speeds, a small wrong decision can lead to a loss of control in a matter of seconds,” FlyaJetFighter wrote.
So control was a problem, and during a flight test on August 11, 2011, personnel lost contact with the Falcon, and it plunged into the Pacific Ocean. It had taken off from Vandenberg Air Force Base in California on top of a Minotaur 4 rocket. Mission control failed to continue tracking and collecting the correct telemetry data, and that was the end of the Falcon.
The Legacy of the Falcon HTV-2
This was a disappointing finale, but DARPA should be given credit for conducting important research flights with a hypersonic vehicle that was so magnificent during its short run.
We can only hope that the data collected was used wisely to help the Conventional Prompt Global Strike programs.
The scientists and engineers involved with Falcon were trailblazers at a time when few knew anything about hypersonic flight.
Let’s hope that other current researchers can stand on the shoulders of these giants in the field.
About the Author: Brent M. Eastwood, PhD
Author of now over 3,500 articles on defense issues, Brent M. Eastwood, PhD, is the author of Don’t Turn Your Back On the World: A Conservative Foreign Policy and Humans, Machines, and Data: Future Trends in Warfare, plus two other books. Brent was the founder and CEO of a tech firm that predicted world events using artificial intelligence. He served as a legislative fellow for US Senator Tim Scott and advised the senator on defense and foreign policy issues. He has taught at American University, George Washington University, and George Mason University. Brent is a former US Army Infantry officer. He can be followed on X @BMEastwood.
