For the first time since the early days of the Cold War, America is lagging behind its international competitors in a technology race with far-reaching military and diplomatic implications. Hypersonic weapons are one of six emerging technologies the Pentagon believes could dictate the outcomes of future conflicts, but as America’s competitors continue to field new hypersonic missiles… the U.S.’ own efforts continue to rack up failures.

So what gives? How is it possible that the United States, with a $700+ billion annual defense budget, can’t get a hypersonic weapon into service while Russia’s military, assigned just $61 billion annually, already has two? Well, the truth, as truths tend to be, is complicated, and as we’ll see a few hundred words from now, that very question may misrepresent the true nature of the hypersonic arms race we now find ourselves in.

Last week, we explored the hypersonic missiles America’s competitors in Russia and China already have in service, and briefly discussed America’s efforts to close the capability gap they represent. Now, it’s time to explore the reasons America has fallen behind in this rapidly advancing field.

Despite leading the world in hypersonic technologies in the ’90s and having plans for hypersonic aircraft dating back to the 1950s, the past two decades of asymmetric conflicts in the Middle East forced a shift in focus away from advancing military technologies and toward the large scale employment of existing combat systems. Like the F-14 and F-22 Raptor, hypersonic missiles were seen as incredibly expensive weapons with no potent threat they were needed to address. Now, with a new Cold War of sorts kicking off between world powers, the Pentagon is making up for lost time the best way it knows how: by throwing a bunch of money at the problem.

In 2020, the Pentagon devoted just over $2 billion to developing hypersonic technologies, including missiles. In 2021, that number jumped to $3.2 billion. It grew once again in the Defense Department’s 2022 budget proposal, with $3.8 billion now earmarked for the effort. All told, there are at least 70 hypersonic programs drawing funds from this pool, seven of which are for publicly disclosed hypersonic missiles.

Hypersonic missiles tend to come in two forms: hypersonic glide vehicles (HGVs) and hypersonic cruise missiles (HCMs). For a refresher on the differences between them, make sure to check out our previous coverage.

Related: What exactly are hypersonic missiles and why do they matter?

Why is the US behind in fielding hypersonic missiles?

The United States is indeed lagging behind the competition in fielding operational hypersonic missiles, but the word operational can be pretty subjective in this context. Russia, for instance, says their premiere stealth fighter, the Su-57, is in operational service despite possessing only a single production aircraft and a dozen prototypes. By American military standards, the Felon would still be many years away from earning that coveted “operational” label.

But the fact remains that the United States still appears to be literally years away from fielding a hypersonic weapon, and in the minds of many, that’s a serious problem.

America isn’t as far behind as you might think

The word hypersonic has a cutting edge connotation to it and recent media coverage of these technologies has treated the realm of hypersonic flight like it’s right out of a science fiction movie. The truth, however, is that hypersonic platforms have already been around for decades, and you’re almost certainly already familiar with a number of them.

The hypersonic barrier is, as we’ve already discussed, Mach 5, or approximately 3,838 miles per hour. At these speeds, air itself becomes the enemy as it impacts the vehicle, creating enough friction to damage or even incinerate most common aircraft and missile materials. The space shuttle, however, regularly exceeded Mach 25, or more than 17,500 miles per hour, during reentry. The Air Force’s current (and secretive) X-37B can also reach these blistering speeds. In fact, practically every ballistic missile and spacecraft mankind has ever launched had been and still is hypersonic in nature.

Related: The X-15 was America’s first piloted hypersonic aircraft

That means, not only does the U.S. already possess a wide variety of hypersonic platforms just like many other nations, even corporations operated by Americans like Elon Musk and Jeff Bezos can claim hypersonic capabilities. That’s not to say that we should adjust the hypersonic weapons conversation to include everything from NASA’s Mercury missions to SpaceX’s latest Crew Dragon flights. Rather, it’s meant to highlight the selective use of the term “hypersonic” in most media to frame the discussion specifically around the capabilities America lacks. That is, after all, the more dramatic story.

“It is very commonly asserted that there is an arms race in hypersonic technology and that the United States is losing,” explained James Acton, who serves as the co-director of the nuclear policy program at the Carnegie Endowment for International Peace and is also a trained physicist.

“But in many ways, the United States is running a different race from Russia and China.”

Both Russia and China, for instance, are exploring reusable spacecraft to aid in their own defense efforts, with China testing their own version of America’s X-37B for the first time in September of 2020, and Russia announcing the development of their own “X-37B-like” reusable spacecraft in March of 2021.

When viewing hypersonics through a lens of reusable military space platforms then, the United States has the resounding lead. The X-37B made its space debut nearly 12 years ago now.

The competition isn’t as far ahead as they seem either

Even in terms of specifically envelope-pushing hypersonic technologies in the contemporary sense of the word, the U.S. again has a solid pedigree.

All the way back in 2004, NASA’s 12-foot long scramjet technology demonstrator known as the X-43A reached Mach 9.6 in testing. In 2011, Boeing’s B-51 Waverider, also a scramjet technology demonstrator, flew under scramjet power for 210 seconds, reaching Mach 5.1. In August of that same year, DARPA’s Falcon Project and its HTV-2 boost-glide vehicle achieved Mach 20 during a nine-minute flight test. And in 2017, the U.S. and Australia conducted a joint test of the HiFire scramjet missile, reaching speeds in excess of Mach 8.

Meanwhile, Russia’s Kh-47M2 Kinzhal (or Dagger), which entered service in 2017, is neither a hypersonic boost-glide vehicle nor is it a scramjet-powered cruise missile. Instead, it’s little more than the first stage of a 9K720 Iskander short-range ballistic missile married to a new targeting apparatus and mounted on the belly of a MiG-31 (or carried inside Tu-22M3 bombers).

Related: What exactly are hypersonic missiles and why do they matter?

In other words, the Kinzhal is an air-launched ballistic missile made of components that were largely designed all the way back in 1988. Like so many of Russia’s highest-profile weapons, the Kh-47M2 is little more than a redress of Soviet-era firepower. While this sort of weapon does offer Russia increased military capability, there’s little practical value in the U.S. rushing a similarly rudimentary design into service beyond garnering press attention, which is, of course, one of Russia’s longstanding strategic goals (making the deployment of the Kinzhal a strategically crafty play).

The United States’ hypersonic missile efforts currently include at least two hypersonic boost-glide vehicles and potentially up to five hypersonic cruise missiles leveraging scramjet propulsion. A scramjet, or supersonic ramjet, is essentially an air-breathing jet engine that reaches combustion with supersonic airflow (unlike traditional ramjets which use shock cones to reduce airflow to subsonic speeds). This type of propulsion allows for incredibly high rates of travel, but it needs to rely on a conventional source of power, whether a ramjet or a rocket booster, to reach those speeds in order to operate well.

Of course, putting a ramjet/scramjet-powered weapon system into service has never been done by any nation before, making it pretty logical that this effort would lag behind Russia’s approach to using old technology and brute force to enter the hypersonic arena. America’s approach will result in a longer timeline to service, but it may well also result in far more capable weapon systems in the long run.

Russia and China both do have hypersonic boost-glide vehicle weapon systems in service, however. Despite America’s previous successes in this specific realm, there’s no denying that the U.S. has yet to match that capability… but there may be good reason for that too.

Related: Russia’s high profile weapons are all smoke and mirrors

America’s focus is on conventional hypersonic weapons

America only has plans to develop new conventional, or non-nuclear, hypersonic weapons at this point, and that poses larger technical challenges than fielding nuclear ones.

Nuclear weapons, as you can imagine, don’t need to be nearly as accurate because of the relative size of their blast radius. A conventional weapon, on the other hand, carries a smaller destructive yield, and as such, must be more accurate in order to destroy its target.

This point was laid out more than once in a recent report on hypersonic missiles published by the Congressional Research Service: