Mission and Programs

In 2003, the Department of Defense (DOD) specifically identified a new mission—prompt global strike (PGS)—that sought to provide the United States with the ability to strike targets anywhere on Earth with conventional weapons in as little as an hour, without relying on forward based forces. DOD argued that this capability would bolster U.S. efforts to deter and defeat adversaries by providing the United States with the ability to attack high-value targets or "fleeting targets" that might be visible for only a short amount of time promptly, at the start of or during a conflict. DOD has considered a number of systems that might provide the United States with long-range strike capabilities. The Pentagon is also conducting research, through DARPA and the Air Force, into shorter-range, air-delivered, hypersonic cruise missiles. Some analysts have questioned the need for these programs, raising concerns, for example, about the possibility that U.S. adversaries might misinterpret the launch of a missile with conventional warheads and conclude that the missiles carry nuclear weapons. This report provides an overview of the rationale for the PGS/prompt strike mission and the possible deployment of conventional warheads on long-range ballistic missiles or boost-glide systems in support of this mission. It then reviews the Air Force and Navy efforts to develop these systems. However, it has continued to support funding for hypersonic technologies in its FY2019 defense budget request. Even without direct substitution, however, CPGS still might reduce U.S. reliance on nuclear weapons, because, with more conventional options, a President might be less likely to authorize the use of a nuclear weapon to attack a critical target. Plans and Programs

Both the Air Force and the Navy have studied the possible deployment of conventional warheads on their long-range ballistic missiles in the past. Air Force Programs

			The FALCON Study

In 2003, the Air Force and DARPA (the Defense Advanced Research Projects Agency) initiated a program, known as FALCON (force application and launch from continental United States) that was designed to develop both a launch vehicle similar to a ballistic missile and a hypersonic reentry vehicle, known as the common aero vehicle (CAV) that, together, would provide the United States with the ability to meet the requirements of the prompt global strike mission. Army Advanced Hypersonic Weapon

The Army also developed a hypersonic glide vehicle, known as the advanced hypersonic weapon (AHW). The capability, even when fully deployed, would be limited by the small number of available warheads. Moreover, funding for the program is expected to increase significantly, from a request for $278 million in FY2019 to a request for $478 million in FY2022, for a total of $1.9 billion between FY2019 and FY2022. Congress authorized and appropriated the requested funds for FY2010. As the CPGS program has evolved in the past 15 years, and as the United States has placed a higher priority on long-range strike and hypersonic weapons in recent years, analysts have questioned the shifting and expanding rationale for the programs. Congress has supported the development of a new land-based intermediate-range missile as a part of the U.S. response to Russia's violation. This technology remains in its early stages, and could not contribute to the PGS mission for several years. They have both noted that, by strengthening the U.S. ability to attack at long ranges with conventional weapons, these systems could help reduce the number of circumstances when the United States might have to consider using nuclear weapons to defend its interests. The same could be true for the adversaries who are the intended targets of U.S. conventional prompt strike weapons. Some have argued that the possible crisis instabilities associated with long-range ballistic missiles should not eliminate them from consideration for the conventional prompt strike mission because the United States can work with Russia, China, and other nations to reduce the risks; also because no other weapons, at least in the short term, provide the United States with the ability to attack promptly anywhere on the globe at the start of an unexpected conflict.
Conventional prompt global strike (CPGS) weapons would allow the United States to strike targets anywhere on Earth in as little as an hour. This capability may bolster U.S. efforts to deter and defeat adversaries by allowing the United States to attack high-value targets or "fleeting targets" at the start of or during a conflict. Congress has generally supported the PGS mission, but restricted funding for several years. Recently, efforts to develop a long-range prompt strike capability, along with other efforts to develop extremely fast hypersonic weapons, have garnered increased support.
CPGS weapons would not substitute for nuclear weapons, but would supplement U.S. conventional capabilities. Officials have argued that the long-range systems would provide a "niche" capability, with a small number of weapons directed against select, critical targets. Some analysts, however, have raised concerns about the possibility that U.S. adversaries might misinterpret the launch of a missile with conventional warheads and conclude that the missiles carry nuclear weapons. The U.S. Department of Defense (DOD) is considering a number of systems that might provide the United States with long-range strike capabilities.
The Air Force and Navy have both pursued programs that would lead to the deployment of conventional warheads on their long-range ballistic missiles. During the 2000s, the Air Force and the Defense Advanced Research Projects Agency (DARPA) sought to develop a hypersonic glide delivery vehicle that could deploy on a modified Peacekeeper land-based ballistic missile, but test failures led to the suspension of this program; research continues into a vehicle that might be deployed on air-delivered or shorter-range sytems. In the mid-2000s, the Navy sought to deploy conventional warheads on a small number of Trident II submarine-launched ballistic missiles, but Congress rejected the requested funding for this program. Since then, the Pentagon has continued to develop a hypersonic glide vehicle, now known as the Alternate Reentry System, which could be deployed on long-range missiles. At present, it seems likely that this vehicle could be deployed on intermediate-range missiles on Navy submarines, for what is now known as the Prompt Strike Mission. Congress may review other weapons options for the deployment of hypersonic weapons, including bombers, cruise missiles, and possibly scramjets or other advanced technologies.
The Pentagon's budget request for FY2019 increases funding for the CPGS program from around $201 million in FY2018 to $278 million in FY2019; it also shows significant increases in funding over the next five years, with a total of $1.9 billion allocated to the program. This shows the growing priority placed on the program in the Pentagon and the growing interest in Congress in moving the program forward toward deployment.
When Congress reviews the budget requests for prompt global strike and hypersonic weapons, it may question DOD's rationale for the mission, reviewing whether the United States might have to attack targets promptly at the start of or during a conflict, when it could not rely on forward-based land or naval forces. It might also review whether this capability would reduce U.S. reliance on nuclear weapons or whether, as some critics have asserted, it might upset stability and possibly increase the risk of a nuclear response to a U.S. attack. At the same time, Members of Congress and officials in the Pentagon have both noted that Russia and China are pursuing hypersonic weapons, leading many to question whether the United States needs to accelerate its efforts in response, or whether an acceleration of U.S. efforts might contribute to an arms race and crisis instability.
This report will be updated as needed.