It travels at speeds in excess of 13,000 miles per hour, weathering extreme temperatures of more than 3,500 degrees Fahrenheit. Engineers and analysts expect this hypersonic glider to one day be capable of delivering a conventional warhead payload to a target anywhere around the globe within 60 minutes.
It’s the fastest aircraft ever built, a technological marvel from the not-too-distant future, a Dr. Strangelove-esque concept rooted in the perpetual race for global military superiority.
Even though the latest such vehicle to be tested is believed to have self-destructed only a few minutes after it began its course, analysts say the test yielded approximately three minutes of data from the stable, aerodynamically controlled Mach-20 flight, which will prove invaluable as research continues in this largely uncharted field.
At 7:45 a.m. on Aug. 11, an arrowhead-shaped Hypersonic Technology Vehicle-2 (HTV-2)—known as the Falcon—hitched a ride out of Vandenberg Air Force Base on a Minotaur IV Lite rocket. After separating from the rocket, the Falcon achieved a few minutes of flight before communication to base command was lost.
Officials confirmed the vessel “splashed down” into the Pacific Ocean somewhere along its flight trajectory. It was heading to the Kwajalein Atoll, some 4,200 miles southwest of Vandenberg. Although the “anomaly” that caused it to fail hadn’t been determined as of press time, the agency developing the new technology said that the recorded data may serve as vital in advancing the government’s knowledge of hypersonic flight.
The glider itself was built by the defense giant Lockheed Martin, under a contract with the U.S. government, for a Defense Advanced Research Projects Agency (DARPA) program. DARPA, the Pentagon’s special high-tech research wing, is responsible for developing and testing new technology for the military, reporting directly to senior Department of Defense officials.
The Falcon HTV-2 program began in 2003, and cost approximately $320 million total, but DARPA won’t reveal individual vehicle or launch costs.
Following the launch, the Minotaur rocket propelled the vehicle to near-orbit before separating. The glider then dipped back down, reentering the earth’s upper atmosphere, and pulled back up slightly in a maneuver to control its altitude and glide. At this point, ground controllers noted that the vessel’s more than 20 air, land, sea, and space data collection and transmission systems were functional.
But after a few minutes into the “glide phase” of the flight, where the HTV-2 was to test its aerodynamic performance, communication went down.
“Range assets have lost telemetry with HTV-2. More to follow,” reads a post on the agency’s Twitter page from during the flight. A moment later, another post announced the agency was unable to reacquire tracking, but noted that the HTV-2 has an “autonomous flight termination capability” or, in layman’s terms, a self-destruct mechanism.
U.S. Air Force and DARPA personnel directly associated with the project are currently wrapped up in working with an independent engineering review board to scrutinize the data collected during the flight, and they didn’t return requests for comment. However, DARPA spokesman Eric Mazzacone shed a little light on the specifics of the program in an e-mail to the Sun.
Mazzacone said the vessel terminating itself during flight wasn’t an indication of failure. On the contrary, he said, the focus of the test wasn’t distance flown, but collecting readings of stable Mach-20 flight. Following the glide phase, the vessel was programmed to self-terminate by diving into the Pacific Ocean anyway, he said. At such speed, very little would remain of the vessel.
“Retrieving the vehicle was never envisioned,” Mazzacone said.
DARPA launched its first hypersonic vessel from Vandenberg in April 2010. That flight had similar results, with base personnel soon losing communication with the vessel. But according to Mazzacone, DARPA staff made modifications to the vehicle’s design based on the results of the April 2011 flight test, including adjusting the vehicle’s center of gravity, decreasing the angle of attack, and using the onboard reaction control systems to augment vehicle flaps. Those modifications appear to have been effective, the agency announced Aug. 14, and whatever anomaly brought down the second flight is believed to be unrelated to the first.
“We’ve confirmed that the HTV-2 made impact with the Pacific Ocean along its flight trajectory as planned in the event of an anomaly,” U.S. Air Force Maj. and program manager Chris Schulz said in a press release. “This flight safety system is a significant engineering advance in that the system prompts a vehicle to monitor the parameters under which it is operating and exercise safety protocols completely autonomously should those parameters be breached.”
Mazzacone said no future flight tests have been scheduled, as the Falcon HTV-2 program was designed for only two flight tests before the technical knowledge gleaned is to be turned over to the Department of Defense.
Hypersonic flight is still considered the new frontier in terms of aeronautical engineering, and though the United States—along with only a smattering of other countries—has tested aircraft capabilities in controlled settings such as wind tunnels, there’s very little flight test data available, said John Pike, defense analyst and director of the public policy organization GlobalSecurity.org.
Pike told the Sun that, to put Mach-20 speeds in perspective, a commercial airliner travels at less than Mach-1, and ground-level tests such as wind tunnels can only yield speeds up to Mach-6. Further development relies on testing in the air, he said.
“The problem is that there is a world of hurt between Mach-6 and Mach-20, and they’ve spent the last 16 years trying to figure out if there is a sweet spot there,” Pike said. “At this point, I don’t believe anybody thinks they have a real handle on it.”
While the latest flight test indicates the U.S. government still has gaps in its understanding of hypersonic flight, Pike said the research and testing is being done on multiple fronts—and the public shouldn’t discount what is, after all, a somewhat secret endeavor.
“In reality, we have no idea what’s going to hop out of the curtain with no warning from the classified community,” Pike said.
Staff Writer Matt Fountain can be reached at mfountain@santamariasun.com.
This article appears in Aug 25 – Sep 1, 2011.