Story originally appeared on Aviationweek.com.
With Russia’s full-scale invasion of Ukraine in its third year, much attention has been paid to the West’s diminishing stockpile of weapons. Manufacturers have scrambled to increase production—or in some cases, restart production—of weapons that have proven vital to Ukraine’s defense. Dire warnings have been issued that we are rapidly depleting weapons stockpiles that our own military might require. At the same time, there are concerns that industry is not positioned to meet the increasing demand for rocket engines, driven in part by plans to produce large numbers of hypersonic weapons.
But lost in the conversation around weapons and rocket engine supplies is the reality that much of U.S. technology associated with solid propellants and explosives—so-called energetic materials—has seen little advance since the end of World War II. This includes not only the materials, but also the methods used to produce them at scale.
Despite decades of research and benchtop demonstration, the field has suffered from a reluctance to employ new manufacturing techniques and a resistance to using new formulations.
Consider that one of the primary ingredients in plastic explosives, RDX, was patented in Germany at the end of the 19th century and entered full-scale manufacturing in the U.S. in the early 1940s. The chemically similar HMX is only slightly more recent. Both are satisfactory, but newer, even more powerful explosives have seen only limited adoption in the U.S. For example, CL-20, invented about four decades ago, holds great promise as a rocket propellant because of its high energy density (20% greater than RDX or HMX) and the fact that it releases less smoke than other fuels. Yet, because of production and environmental challenges, few American weapons have incorporated CL-20; meanwhile, China has been using it in rockets for more than a dozen years. This is another example of an American invention that a competitor has embraced while we dither.
Our reluctance to incorporate new formulations is compounded by a production infrastructure that is mostly outdated and vulnerable to supply chain interruption. Key ingredients in energetic materials come from foreign suppliers, including peer competitors and potential adversaries. The processes used for munitions manufacturing are far from state of the art. In many cases, U.S producers still utilize so-called batch processing, which is best suited to producing small amounts of material with unique requirements. Industry could benefit from switching to methods more suitable to producing large quantities of chemical compounds such as continuous processing, which speeds up production and reduces waste and energy requirements and which, if done correctly, can be safer than batch methods. Advanced mixing techniques could enable the production of energetic materials more efficiently and more safely than current methods.
The field of energetic materials is poised to benefit from the revolution in manufacturing made possible with additive techniques. This will reduce the costs of some manufacturing processes and even enable the manufacturing of complex shapes that cannot be made with traditional methods. Additive manufacturing holds the promise of tailored warhead designs and rocket engines that are optimized for enhanced performance. Additive processes for energetic materials are already being explored extensively in select university laboratories and have made their way into industry. If it can be scaled effectively, this could represent the future of solid rocket engine and warhead production.
The energetic materials field would also benefit from advances in related disciplines. For example, the pharmaceutical industry has made great strides in applying advanced algorithms to the identification of new disease-fighting molecules. Similar advanced software can be used to identify promising new high-energy materials with a wide range of desirable properties. Likewise, new methods in bioindustrial manufacturing could lead to production techniques that have significant application to the energetics industry.
If we are to meet the challenges of our peer competitors and satisfy the needs of our industry, we must invest not only in increased production of new warheads and engines but also in modernizing the underlying energetic materials and means of production, including pyrotechnics, explosives and propellants.
As is true in so many areas of aerospace technologies these days, the development of energetic materials has been allowed to languish, almost taken for granted. This must change, for we cannot meet the needs of a 21st-century military with energetic material formulations and manufacturing processes from the 19th century.
Mark Lewis is the first president and CEO of the Purdue Applied Research Institute and was director of defense research and engineering for modernization at the Pentagon.