Hypersonics: Past Failures Not an Option

Retired Air Force Lt. Gen. David Deptula at a Capitol Hill briefing asked the audience for a show of hands: How many were aware that China had conducted six hypersonic vehicle experiments over the past two years — three in 2014 and three in 2015?

Many hands in the relatively knowledgeable crowd went up.

“I would dare say if you went to any other portion of this august building and asked that question, they wouldn’t know,” said Deptula, now the president of the Mitchell Institute of Aerospace Studies.

For those who have followed his career, Deptula has been a leading proponent of the development of missiles and aircraft that can reach speeds of over Mach 5.

Deptula, along with retired Air Force Maj. Gen. Curtis M. Bedke, made no secret that they wanted congressional staffers in the room to take the institute’s new report, “Hypersonic Weapons and U.S. National Security: A 21st Century Breakthrough,” and use it as a means of influence. They want a serious program that will lead to fielding hypersonic vehicles in the next decade.

“We wrote this paper primarily with congressional staffers as the readership,” said its co-author Bedke. It is a mere 25 pages long and doesn’t get bogged down in technical details and the long history of failed programs.

But what they didn’t want is for one of the staffers to run upstairs and convince his or her elected representative to “eat the entire elephant all at once.”

The history of hypersonic technology is littered with the corpses of failed programs, or vehicles that succeeded in some way, but didn’t result in fielded technology.

The X-15, X-30, X-33, X-34, X-43, X-51 and the Blackswift are the ones that come to mind. That has led some to say that hypersonic technology has been the weapon of the future for the past 40 years.

“We try to solve all the problems with one big project often because senior leaders are enamored of this idea, or they are blind to the complexity of the project, or they are unwilling to accept the true costs and risks necessary for success,” Bedke said.

The United States needs “a steady and disciplined program and to see that the wasted opportunities of the past are not repeated,” he said.

There are U.S. hypersonic research programs being conducted, he acknowledged, and they are doing good work to solve some of the underlying technical problems. The Defense Advanced Research Projects Agency, the Air Force, the Navy and NASA are all devoting research-and-development dollars to hypersonics.

The report recommended bringing all of these efforts under one roof, namely that of the Air Force. 

There are two approaches to developing hypersonic weapons.

One is called boost-glide. A rocket lifts a vehicle high into the atmosphere, then releases the glider that reaches Mach 5 plus speeds upon descent. This is the method China is testing.

The other is an air-breathing engine on a cruise missile-type vehicle. This approach, similar to jet engine technology, doesn’t require large boosters or a lot of fuel.

The report doesn’t favor one approach over the other and Bedke said to drop one of them in the name of budget cutting would be a mistake. Current programs give the impression that everything is fine and there is nothing to worry about. But bringing a program under one roof, with steady funding to tackle the technology challenges in an incremental way, would assure that the program “isn’t just being kept on life support,” he said.

Deptula had stronger words: “We can’t afford to continue treating hypersonics as a science fair project. It’s time to stop being a follower in hypersonics and start being a leader.”

Russia has announced a program, and has worked on high-speed missiles with India. The two countries want to break Mach 5, Bedke said. The Chinese may have demonstrated complex maneuvers in some of its recent tests.

“They are inevitable for somebody to develop,” he added.

There are still many technological hurdles. Hypersonic weapons will need to travel at farther distances for a longer period of time, he said.

 “At these speeds the heat is not just intense, it is so incredible the air begins to ionize, individual molecules break apart and start to shed electrons,” he said. One of the main problems is simply ensuring that the aircraft doesn’t burn up, he added. “We have to figure out how not to melt. It’s not a trivial problem to solve and it has frustrated a lot of people for a long time."

There were reporters in the room asking the tough questions — namely how much do you think this is going to cost and where on Earth is the Air Force — if it is named an executive agent for the program — going to find the funds to pay for it? The earliest tests currently planned don’t come until 2019 or 2020. That just happens to be when the service has to pay for a slew of F-35s, B-21 long-range strike bombers, a couple hundred new jet trainers and joint surveillance and attack radar systems recapitalization. Budget hawks look at research-and-development programs as easy pickings. 

“I’m a realist,” Bedke said. “I understand that there is a lot on people’s plates but a good, steady well-disciplined program will not cost a heckuva lot of money.”

The other uncomfortable question is defense. Even if the U.S. military dropped everything else it was doing and devoted billions of dollars to a dedicated hypersonic weapons program, it wouldn’t necessarily stop the Chinese from fielding its own system. How do you stop a missile traveling at Mach 8 from striking a U.S. military base in Texas?

“That is another topic for another time,” said Bedke.

Topics: Armaments, Science and Engineering Technology