In 1967, the United States, United Kingdom and Soviet Union came together to sign a document that, at the time, seemed like a pressing concern: the Outer Space Treaty. It not only established the framework for an international set of laws governing the use of outer (and orbital) space, it set important precedents about what national militaries could do in orbit. Chief among those limitations: barring weapons platforms from being deployed on satellites.

Of course, in the intervening years, nations (including the United States) have sought ways to circumvent the rules established in that treaty. There are no rules banning the use of defensive systems in orbit, like the satellites the U.S. relies on to identify and track missile launches, but to date, no nation has openly defied the intent of the treaty by deploying offensive assets in orbit… or at least, no nation has done is publicly. Both Russia and China have invested heavily in weapons systems that can interfere with or even shoot down orbiting satellites, and both nations have experimented with mobile “drone” satellites that could easily be used to disrupt, damage, or even destroy integral elements of America’s satellite infrastructure — relied on for everything from navigation to communications to reconnaissance.

While China and Russia both already have space-specific branches of their own militaries operating, President Trump’s recent directive to establish an American Space Force was met with a great deal of domestic criticism, as well as what seemed at the time to be misplaced concerns among Russian officials that America would inevitably begin deploying legitimately offensive platforms in space.  Like much of the rhetoric from the Kremlin, those concerns were readily dismissed by most who, understanding the nature of the threat to America’s orbital assets, saw no real strategic value in loading rockets full of ordnance and launching them into the sky.

However, recent statements from Michael Griffin, Undersecretary of Defense for Research and Engineering, seems to suggest that the U.S. is at least considering taking a more aggressive approach to its space endeavors. According to Griffin, the best way to counter Chinese and Russian hypersonic missile technology is to deploy a network of 1,000 missile interceptors on orbiting satellites, ready to deploy and engage offensive launches anywhere they may threaten America or her allies.

“In brief, we do not have systems today that give us globally, comprehensive, persistent, timely, multi-mode awareness of what is going on on earth, everywhere, all the time. We don’t have that,” Griffin said this week. “And the Chinese hypersonic threat is one that in today’s world, we cannot see coming until it’s too late. So it is up to us to defend that. And in order to defend that order we must now go to space … both for the sensory layer and the ability to project power.”

While this proposed platform is being presented as purely defensive in nature, there can be no doubt that America’s competitors will see (or at least argue) that any sort of kinetic interceptor, particularly missiles, could be used offensively as well as defensively in orbit.

Perhaps the most intriguing part of this proposal is how it relies heavily on existing technologies, making the total cost of development and deployment a fraction of what other defense programs may require. Griffin estimates that the entire program would cost around $20 billion. A single Ford class aircraft carrier costs in the neighborhood of $13 billion and the F-35 program is expected to approach $1.5 trillion throughout the extent of its lifetime.

Cost effective as Griffin’s proposal may be, he didn’t offer much in the way of technical specifics — which would be as serious concern when talking about intercepting hypersonic missile platforms. Most hypersonic missiles come in one of two varieties: those that fly with a near horizontal flight path, and those that follow a more traditional long range ballistic missile arc that takes them into or near low earth orbit before reorienting and “gliding” at hypersonic speeds back down to its target. Orbital defenses would likely be tailored for the latter, hoping to intercept during the midcourse of the missile. Any missile intercept, even at subsonic speeds, is incredibly complex. Doing so from unmanned orbital stations targeting hypersonic projectiles may be a technical hurdle that could blow Griffin’s cost estimates out of the water.