They unleash destruction traveling at five times the speed of sound. They maneuver with computerized precision while descending back into the earth’s atmosphere toward a target. Their speed and force are so significant, they can inflict damage by sheer “kinetic” impact without needing explosives.
They can destroy Navy ships, air defenses, ballistic missiles, ground targets and aircraft in a matter of minutes or even seconds, depending upon the launch point……. they kill in an instant --- seemingly coming out of nowhere.
They --- are Hypersonic weapons.
Many senior Pentagon weapons developers share a common view; hypersonics are nearly impossible to defend against, ushering in an unprecedented tactical reality bound to reshape warfare and force unforeseen strategic adaptations.
How can carrier strike groups project power within striking range of enemy targets? How can mechanized armored columns maneuver without being badly crippled by hypersonic attack? How can the most advanced fighter jets maneuver to avoid impact if there simply is no time? Perhaps satellites, ICBMs and defensive weapons such as Ground-Based Interceptors could also be vulnerable? The variables through which hypersonics promise to alter warfare are seemingly limitless. The danger is extremely serious.
Of equal or greater concern, hypersonics are no longer something to envision for a distant future -- they are now being prototyped, tested and refined. In short, they are basically here. U.S. weapons developers have put them on the fast track and expect to have operational hypersonic weapons in a few years, if not sooner.
An Air Force chief scientist once told Warrior that the U.S. technical approach to hypersonics is one of stair steps following a particular trajectory. First hypersonic weapons emerge in the early 2020s, to be followed by hypersonic drones in the 2030s leading up to the distant possibility of launching “recoverable” hypersonic platforms by the 2040s. However, given the pace of technical progress, this notional timeline could easily become massively accelerated. The current threat environment, we often hear, is creating a sense of urgency.
“In the last year, China has tested more hypersonic weapons than we have in a decade. We’ve got to fix that,” said Michael Griffin, the Undersecretary of Defense for Research and Engineering, according to an Air Force report from February of this year.
The real problem hypersonic weapons present for adversaries -- is speed. Kinetic energy weapons exist, ballistic missiles exist and space-traveling weapons exist, but hypersonic weapons drastically change “sensor-to-shooter’ time. In effect, if commanders have merely a fraction of the response time associated with most existing weapons, how can they defend?
But …..wait a second… before anyone becomes resigned to cataclysmic destruction… just what if there were a viable way to defend against hypersonic weapons? What if they could be destroyed or disabled before hitting a target?
This, according to Pentagon and industry weapons developers… is possible. In fact, U.S. weapons developers are already working on it.
While naturally many details of these emerging methods are not available due to security reasons, there are three broad categories of current inquiry, according to senior industry weapons developers -- lasers weapons, modifying existing interceptors or simply engineering new kill vehicles, Ret. Lt. Gen. Trey Obering, Executive Vice President and Directed Energy Lead, Booz Allen Hamilton, told Warrior in an interview. (Obering previously served as the Director of the Pentagon’s Missile Defense Agency)
Tracking Hypersonic Weapons
Industry weapons developers explain that simply “tracking” approaching hypersonic weapons can be described as a key starting point when it comes to exploring these options. While there are of course a wide range of air, sea and land sensor technologies, tracking hypersonics will rely heavily upon satellites. Current satellite-mounted Spaced Based Infrared (SBIR) sensors can now detect the heat signature of an enemy ICBM or ballistic missile launch. The intent with SBIR is to transmit that information to land-based warning systems and instantly activate response protocols, but SBIR systems cannot themselves “track” the flight of a hypersonic weapon. However, the prospect of engineering a satellite, or group of satellites, with the technical capacity to track hypersonics -- is very realistic.
“We’ve got to be able to track them through their flight. We know their trajectory once they are out of the boost phase. You are going to have to track precisely enough so you can engage it with an interceptor,” Obering said.
"We are collecting a lot of data on how this can be done,” he added.
A way to do this, Obering explained, would be to engineer a group of networked, lower-flying Very Low Earth Orbit satellites able to cover large swaths of territory. Although they cover more narrow areas than larger satellites and use more focused sensors, smaller satellites traveling closer to the earth can move faster, detect objects with greater fidelity in some cases and use advanced processing speeds to network key sensor data.
“We need enough satellites. We need to build a constellation that can track these weapons. We would have to have enough of them at the same altitudes,” Obering said.
Obering traced the technical basis for this kind of tracking to two demo satellites launched in 2009 used to track ballistic missiles. “We can generate a track from space on a ballistic missile, and maneuver it precisely to engage it with an interceptor,” he said.
Retired Lt. Gen. Chris Bogdan, Senior Vice President and a leader in Booz Allen’s Aerospace business, says emerging iterations of machine learning and artificial intelligence can help process sensor information, perform analytics and succeed in organizing target-crucial data with much greater speed than existing technology can. This naturally bears prominently on the time-challenge when it comes to defending against hypersonics.
“Machine learning and high-speed computing regarding sensor data can collapse those timelines down,” Bogdan told Warrior. (Bogdan is the former Program Executive Officer for the Pentagon's F-35 program)
With AI and certain kinds of machine-learning, new data can instantly be compared against a vast and seemingly limitless database of stored information to organize information, solve problems and instantly give human commanders essential information. Should a meshed network of fast, moving low-orbiting satellites have an ability to share target information quickly, it could make an enormous difference when it comes to defending against hypersonics. Advanced algorithms can, among many things, process enormous volumes of ISR data and quickly pinpoint moments of relevance for human decision-makers. This can, as Bogdan points out, exponentially reduce any kind of response timeframe.
Once tracked, of course, hypersonic weapons would need to be destroyed, disabled or rendered useless. Among several options, space, air and even some ground-based lasers may offer the greatest near-term promise.
“With a laser, we could burn a hole through it and cause it to fail. Lasers can fire energy into a very narrow point,” Obering said.
Also, when it comes to countering the speed of hypersonics, lasers travel at the speed of light - faster than hypersonic weapons. Therefore, from a command and control perspective, lasers might be able to help defending commanders somehow get in front of the sensor-to-shooter cycle.
The way a layered defense of hypersonics might work, Obering explained, is to use satellites to track the approaching weapon and then transmit targeting data to laser weapons or some kind of interceptor. Given that a hypersonic missile launches like a ballistic missile and then becomes a maneuvering “glider” in space, “The best defense would be during the boost phase. You want to destroy them before they get into their maneuvering phase,” Obering said.
From an operational standpoint, lasers are ideal weapons for space; the thin air reduces beam attenuation, enabling increases in functionality, precision, range and power. While satellite fired lasers are not here today, the Pentagon and industry are working on technology which might very well be able to accomplish this a few years from now. Yet another laser application might be to use some kind of laser-armed drone-type vehicle to operate at the highest altitudes in the earth’s atmosphere.
“We might put an unmanned aircraft where the air is thin. How high could we get a drone?” a senior Pentagon official told Warrior.
Pentagon weapons developers tell Warrior the main focus, at the moment, is work on laser scaling to engineer effective weapons with varying degrees of range and power. Part of this effort, U.S. military weapons developers say, is to maximize the power of transportable laser weapons.
“We want to have something portable that could be used in a small platform, combining a strong beam in a small form factor,” the official said.
Also, in addition to operating as offensive or defensive weapons able to destroy targets, lasers can also be used as sensors to quietly perform ISR at long distances. This sensing technology might prove particularly useful at longer ranges. “Lasers will burn through steel at 500 meters, but at longer ranges they might help pinpoint a target,” the senior Pentagon official said.
In application, this could mean having a surface Navy ship help track hypersonic weapons at high altitudes within or just beyond the earth’s atmosphere. It could also mean deploying laser-sensors on satellites able to both sense and destroy targets.
Are Hypersonic Weapons Vulnerable?
“Hypersonics are fragile aerodynamically and thermally,” Obering said.
Obering’s discussion of the thermal “fragility” of hypersonic weapons is further reinforced by an interesting RAND Corporation paper which explains why hypersonic weapons have a larger heat transfer than Re-entry Bodies releasing from an ICBM. The comparison, as discussed in the RAND essay, takes up what seems to be an extremely relevant question, given that Re-entry bodies also travel at hypersonic speeds when re-entering the atmosphere.
Increased heat can bring challenges; it strengthens the weapon's thermal signature, making it easier for sensors to track. Heat challenges can also introduce difficulties by creating a need to engineer a weapon able to withstand the heat levels and remain intact during high speed flight. For this reason, hypersonic weapons -- and ICBMs as well -- are constructed with specially engineered heat-resistant materials.
The RAND essay, called “Hindering the Spread of a New Class of Weapons,” explains that heat signatures are impacted by the shape, size, velocity and trajectory of a weapon.
“The larger the nose radius, the smaller the heat transfer on the nose of the vehicle. Trajectory shaping, i.e., velocity and altitude, can also be used to manage the total heat transfer on an RV (Re-entry Vehicle) while meeting other input requirements and constraints, e.g., range, maximum deceleration, and time of flight. Hypersonic weapons have different constraints and requirements compared with reentry bodies. HGVs (Hypersonic Glide Vehicles) and HCMs(Hypersonic Cruise Missiles) will tend to have sharp leading edges, i.e., a small nose radius, which will increase the heat transfer,” the essay states. (RAND - Speier, Nacouzi, Lee)
Hypersonic weapons, the essay further explains, need to travel for long periods of time at high speeds, when compared to a re-entry body.. therefore… “two of the major parameters in the total heat equation, velocity and time, cannot generally be reduced,” the paper states.
Hypersonic weapons could also potentially be stopped by, as Obering put it, causing a “disruption in the airflow.” Changes in aerodynamics can break up forces such as lift, thrust and drag, Obering said.
“These forces are all in balance. When you are going fast there is a small margin in those forces. A disruption can cause the entire vehicle to break up,” he explained.
Essentially, the idea is not to destroy the hypersonic weapon with an explosion, but rather cause an “instantaneous” angle change in the complex, interwoven mixture of air-flow variables. This, quite significantly, can cause an entire vehicle to break apart. A number of things could cause this, such as a laser, rupture of a booster, missile explosion in the vicinity of the weapon in-flight or some other kind of disruption.
“Hypersonics have control surfaces that can maneuver like an aircraft. You would take advantage of the vehicle’s speed and cause a change in vehicle direction,” Obering said.
Causing this kind of change would be made possible, in part, due to the fragility of certain elements of hypersonics flight, such as control, heat and aerodynamic stability.
“Igniting the engine of a hypersonic cruise missile has been compared to lighting a match in a 2,000-mile-per-hour wind. Moreover, the shape of the missile changes under the rigors of hypersonic flight, creating great challenges for flight control,” writes Richard Speier in a separate RAND essay called “Hypersonic Missiles: A New Proliferation Challenge.