The technological challenges of developing reliable, deployable hypersonic weapons

Of all the forward-looking defense technologies under development to counter perceived threats of the next several decades, hypersonic weapons represent the one with the highest sense of urgency. The reason these future Mach-5 weapons are getting so much attention is the nation’s military leaders believe the U.S. is behind — perhaps far behind — its chief military rivals, Russia and China.

Hypersonic weapons are particularly scary because today there’s no way to defend against them; they’re just too fast. These kinds of weapons are considered so formidable and beyond any of today’s missile defenses that they will be in the 2020s what some of the first reliable intercontinental ballistic missiles were in the 1960s — the focal point of billions of dollars in research and development to build ever-faster hypersonic weapons, and new ways to counter them. Military & Aerospace Electronics tracks some of the trends in our special report feature on page 14.

Remember President Ronald Reagan’s Strategic Defense Initiative (SDI) “Star Wars” program back in the mid-1980s to defend against Soviet nuclear ballistic missiles? We’ll probably see much the same thing with regard to hypersonic weapons by the 2030s — perhaps much earlier. It all comes down to how soon Russia and China (and perhaps others) can build the first reliable and deployable hypersonic missiles.

Hypersonic weapons stand out because of their speed. Today a weapon is considered hypersonic if it could achieve Mach 5. That’s about 3,800 miles per hour, or one mile per second, which is twice the speed of a bullet. Future generations of hypersonic weapons could be expected to exceed Mach 5 by a wide margin.

The U.S. Air Force is working with the Lockheed Martin Corp. Space Systems segment in Huntsville, Ala., on the Hypersonic Conventional Air-Launched Strike Weapon program to develop a Mach 5 hypersonic weapon. This would be for jet fighter and bomber aircraft to provide a prompt precision-strike capability against high-value, time-critical fixed and relocatable surface targets, like enemy warships.

Ships at sea typically would have less than a minute to react after detecting the launch of hypersonic missiles fired their way. Effective defenses are likely to involve detection at extremely long ranges, and technologies able to destroy or disable incoming weapons at much longer distances than today’s technology allows.

Despite their potential as offensive weapons, however, here’s something to think about: there’s a lot of hype behind hypersonic weapons. Today their value in political propaganda is much higher than it is in real firepower. Are the U.S., Russia, and China near to developing deployable hypersonic weapons? It’s hard to say, but there are substantial technological challenges involved.

First, it’s no easy feat to control a weapon moving twice as fast as a bullet, and the ability to control a hypersonic vehicle is critical; just because you can propel a weapon through the air at Mach 5, doesn’t mean you can hit what you shoot at.

There are environmental conditions to consider. Something going that fast generates a lot of heat, shock, vibration, and other environmental extremes because moving through the atmosphere at speeds like that is like a spacecraft during re-entry. The Mercury, Gemini, and Apollo spacecraft needed sophisticated heat shields to prevent them from burning up on re-entering the Earth’s atmosphere. Even the Space Shuttle needed heat shielding; it was this shielding’s failure that caused the Space Shuttle Columbia to disintegrate on re-entry in February 2003.

Heat is an issue not just for the weapon itself. Its guidance systems, sensors, sensor processing, communications, and other electronics also must be able to survive the heat, as well as the anticipated shock and vibration of hypersonic flight. Do we have enabling technologies yet to protect the hypersonic weapon, its electronics, and weapons payload during torturous high-Mach flight? That’s not clear, but believe me, military leaders and defense contractors are working on it.