A top-secret US government body called the Defense Advanced Research Projects Agency (DARPA) has launched a new solicitation seeking proposals for a high-rate, energy-efficient method of producing nitric acid directly from air and water.

The initiative, known as the High-Efficiency Nitrogen Oxidation, or HNO3 program, is aimed at protecting critical U.S. defense-industrial supply chains and reshaping how energetics are produced in contested environments.

According to DARPA, the agency is requesting “innovative proposals in the foundational technologies to enable high-rate, energy efficient, decentralized nitric acid manufacturing to protect critical supply chains in the defense industrial base.”