WASHINGTON, D.C. – Although hypersonic weapons might seem like relative newcomers, known advantages of these weapons are both self-evident and multi-faceted as they can be fired from much greater stand-off ranges while having vastly increased ability to defeat, circumvent or simply destroy enemy air and ballistic missile defenses.
USAF Research Laboratory is working round-the-clock on hypersonic weapons designed to come in the next 10-15 years, in order to “expand USAF’s mission options” in the next decades, as an increasingly contested airspace is emerging, limiting US strike capabilities.
The Pentagon has been aggressively pushing for hypersonic weapons development, especially after Russian advances in this field have left the US trailing behind. Given the implications associated with firing weapons able to travel at over five-times the speed of sound, a number of programs have been underway (reportedly, there are up to 8 US hypersonic programs currently underway).
Right now, the most optimistic estimate is that an initial set of more primitive US hypersonic weapons will be operational by the mid-2020s. In late June 2019, USAF conducted its first prototype hypersonic missile flight test, with a B-52 bomber launching a sensor-only prototype of the AGM-183A ARRW (Air-Launched Rapid Response Weapon).
Despite some initial success with basic hypersonic design testing and development, there is still much more work to be done when it comes to refining the technology needed for current and future hypersonic weapons flight. Engineering a weapon to fly at 5+ times the speed of sound primarily relies on its ability to survive and neutralize (or at least minimize) the heat generated by extreme speeds.
An area of focus relates to several complex aerodynamic challenges, such as managing the airflow surrounding the vehicle in flight. Referred to by scientists as a “boundary layer”, the airflow characteristics of a hypersonic weapon’s flight trajectory greatly impact the survivability and stability of the system – most of which relate to temperature, as excessive heat at such speed can incinerate the weapon.
Increased heat also brings other challenges, as it increases the weapon’s thermal signature, making it easier to detect and track. For this reason, hypersonic weapons – and ICBMs as well – are constructed with specially engineered heat-resistant materials.
“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 a 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,” a RAND (Speier, Nacouzi, Lee) essay states.
”Also, most hypersonic weapons need to travel for long periods of time at high speeds, when compared to a re-entry body traveling at relatively short distances, therefore, two of the major parameters in the total heat equation, velocity and time, cannot generally be reduced,” the RAND paper states.
Many hypersonic weapons are engineered as kinetic energy strike weapons, meaning they will not use explosives but rather rely upon sheer speed and the force of impact to destroy targets. In addition, hypersonic missiles can also be armed with both nuclear and conventional payloads.
US Armed Forces are currently faced with both tactical and strategic implications of hypersonic weapons. How can carrier strike groups “project power” within a striking range of hypersonic missiles? How can mechanized armored columns maneuver without being badly crippled by hypersonic attacks? How can fighter jets maneuver to avoid impact by hypersonic SAMs, which Russia already fields?
What’s more, low orbit satellites, ICBMs and ballistic missile defense weapons such as ground-based interceptors are also vulnerable. The variables through which hypersonics alter warfare are basically limitless. The dangerous implications for aggressive Western-style warfare are extremely serious.