As Russia and China achieve new milestones in their hypersonic development, the United States is frantically looking to build an impregnable defense system.
US Navy Vice Adm. Jon Hill, the head of the US Missile Defense Agency (MDA), recently said that the multi-purpose SM-6 missile is the only weapon in the country’s inventory that can intercept highly maneuverable hypersonic threats.
This follows the agency’s announcement last year that it intends to test an undisclosed version of the SM-6 against an “advanced maneuvering threat,” a word normally associated with unpowered hypersonic boost-glide vehicles, perhaps in the fiscal year 2024.
Hill was speaking about the SM-6 during a discussion regarding hypersonic defensive capabilities at the American Society of Naval Engineers’ Combat Systems Symposium, which began on January 31.
The SM-6 series “is really the nation’s only hypersonic defense capability,” Hill said, without specifying any particular version of this missile. He added that these weapons have a “nascent capability” to engage incoming hypersonic threats.
“We didn’t call it that back when we got the letter from the CNO [Chief of Naval Operations], the Navy’s top uniformed officer to go develop this program,” he explained. “But the whole idea was to handle high-speed maneuver.”
These comments are significant and are the testimony that the United States acknowledges that intercepting a hypersonic glide vehicle is a very difficult task.
Unpowered hypersonic boost-glide vehicles typically require a rocket booster to achieve the desired speed and height. The vehicle is then detached from the bulk of the weapon and begins gliding back down along an atmospheric trajectory toward its target at hypersonic speed.
They are designed to be able to make rapid and unanticipated shifts throughout their flight paths, especially when compared to typical ballistic missile trajectories that follow a fixed trajectory.
This mobility, combined with their high speed and general flight profile, makes them extremely difficult to detect and track, particularly with sensors meant for normal ballistic missiles.
Neither MDA nor the US Space Force has stated how far they can monitor hypersonic weapons or how near the US is to intercepting a hypersonic missile. Hypersonic missiles can fly low and maneuver during the cruise phase, evading radar.
They are designed to destroy high-value targets fast, such as aircraft carriers, as previously stated by Air Force Magazine.
Only the SM-6, one of the 10 primary missiles that arm the Navy’s 285 surface ships and submarines (and counting), is capable of striking targets at sea, in the air, and at the edge of the atmosphere.
New missions are only added to this current missile via software upgrades, as part of Raytheon Technologies’ attempt to quickly deliver new capabilities in the hands of US and allied forces, according to the company.
Teamwork = Success! 💥 #USSJohnFinn (DDG 113) launches an SM-6 missile during @USPacificFleet #USXIBP21, striking the target. UxS IBP 21 integrates manned & unmanned capabilities into challenging scenarios to generate warfighting advantages.
— U.S. Navy (@USNavy) April 27, 2021
The SM-6 currently has two variants in service, Block I and Block IA, with a third variant, Block IB under development. Block IB missile is significantly different from the previous two variants, with a fully new fuselage and a larger rocket motor. The most spectacular thing about the Block IB variant is that it is expected to be capable of reaching hypersonic speeds and, as a result, to have improved capabilities against hypersonic threats.
However, during an MDA-led test last year, the US Navy fired a pair of SM-6 Dual IIs, a ballistic missile defense-optimized sub-variant of either Block I or Block IA. Those interceptors were unable to destroy a dummy medium-range ballistic missile, the MDA had said in a release.
SM-6 Dual II test record:
FTM-31, Event 2 (2019): Shot down cruise missile target
FTM-31, Event 1 (May 2021): Missed medium range ballistic missile target
FTM-33 (July 2021): Shot down one short range ballistic missile target & unknown status of 2nd SRBM target
FTM-32: TBA https://t.co/Zl4hEjrtAf
— Steve Trimble (@TheDEWLine) July 26, 2021
Hill appears to have revealed that the Block I and IA missiles already have some capacity against these more agile hypersonic threats, or were constructed with that capability in mind from the very start. It’s probable that just a few SM-6s now in operation have this capability, which could be the result of post-delivery changes, according to The Drive.
Beyond that, the envelope inside which a current SM-6 may combat hypersonic threats may still be quite small, and the missile may only be useful against particular sorts of targets.
While the SM-6 could be useful to defend against an impending hypersonic glide vehicle attack, the United States has not put all its eggs in one basket. For developing an advanced hypersonic defense system, it remains invested in the ‘Glide Phase Interceptor’ project which is currently under development.
The US military is likewise seeking to fill gaps, particularly by developing a space-based Hypersonic and Ballistic Tracking Space Sensor (HBTSS). Northrop Grumman and L3Harris have been roped in by MDA to build prototype HBTSS satellites, with the objective of beginning on-orbit testing of the two designs in 2023.
American Defense Against HGV
On November 19 last year, the Pentagon revealed that Northrop Grumman, Lockheed Martin, and Raytheon had been chosen to design the Glide Phase Interceptor.
The interceptors would be designed to counter a hypersonic weapon during its glide phase of flight (once a missile has re-entered the earth’s atmosphere and is heading toward its target), which is difficult to predict because hypersonic missiles fly at five times the speed of sound and perform rapid maneuvers, making their trajectory difficult to predict, as previously reported by EurAsian Times.
The interceptors are expected to be manufactured to be integrated into the US Navy’s current Aegis Ballistic Missile Defense destroyers. It would be fired from its conventional Vertical Launch System and linked to the Baseline 9 Aegis Weapon System, which detects, tracks, controls, and engages hypersonic threats, according to the statement.
However, as ambitious and efficient this system sounds, it has essentially hit a funding snag at the moment, according to Defense News.
“The best answer I can give you in this environment today: … We live in a world right now where we don’t have current year appropriations, and we also don’t have insight into the following year’s top line. So, unfortunately, that throttles this program,” Hill said.