A Laser Phalanx?
The Mk15 Phalanx system was originally developed as a ship’s final hope against incoming missiles: a radar-guided 20mm gatling gun would would fire up to 6,000 rounds per minute, throwing up a last-ditch wall of lead. Phalanx has become a popular naval weapon that’s also effective against helicopters, UAVs, and even small boats. It has even migrated onto land, where its “Centurion” version can protect a 1.2 km square area against incoming mortars and rockets.
In September 2007, Jane’s reported from the British DSEi exhibition that Raytheon is working on a Phalanx variant that can fire lasers. Kevin Peppe, Raytheon’s Phalanx program director, said that:
“The Centurion system has provided a near-term C-RAM (Counter-Rocket, Artillery and Mortars) solution for our deployed forces. But we know that our customers would like a larger defended footprint beyond the kinematics of a gunbased system. A missile is too expensive, so we are looking instead at a solution based on the adaptation of a robust but relatively lowpower, low beam-quality commercial laser… By using clever optics to focus the laser beam at range, we demonstrated that we could achieve sufficient energy on target to deflagrate a 60mm mortar round.”
The concept has promise – but it also has substantial obstacles to overcome before it can become militarily useful…
Laser Phalanx: Obstacles and Issues
According to Peppe, a Laser Phalanx solution would offer an effective range about 3 times that of the existing M61A1 20mm gun, along with lower life-cycle costs.
A laser-based Phalanx system certainly sounds interesting. Nevertheless, there are a number of hurdles to cross and tests to pass before it can be considered a true advance over the current set of slug-throwing “last chance” systems out there.
The first obstacle is the requirement for more powerful solid-state lasers, which can fit into a similar “footprint” as existing Phalanx weapons, and are rugged enough to survive the abuse dished out by salt spray, sand, and other inherent hazards of military existence. Most mortar rounds are larger than the 60mm bombs used in the tests, as are the rockets that featured so prominently in the 2006 Lebanon proxy war.
The second obstacle is the environment, which does more than just dish out maintenance-related abuse. Naval deployment would be affected by atmospheric humidity and fog, for instance, or by rain. They weaken lasers, but have very little effect on radar-guided cannon.
The third obstacle is uniquely naval: the growing reality of supersonic ship-killer missiles. Their speed, and ability to perform evasive maneuvers on final approach, gives them added advantages against any weapon that must be held on target for a period of time in order to work. Worse, even pieces of supersonic missile pieces have enough kinetic energy to cause a lot of damage to a ship, unless the incoming object is slowed or deflected by an opposing kinetic force. A naval defense laser, therefore, would require enough power to burn through enemy missiles almost immediately. It would also have to work in such a way that large supersonic missiles either fragment into relatively small pieces when hit, or can be killed far enough away thanks to timely engagement, extra range, and sufficient burn power at range. Even in adverse weather conditions.
A 4th obstacle applies more strongly to land-based lasers. A 20mm cannon shell has a finite range, and can be designed to detonate after a prescribed distance for safety. This protects people on the ground under the shell’s flight path, and also provides a margin of safety to aircraft flying near protected bases. A laser doesn’t have that option, and the same power requirement that ensures fast-enough kills on incoming rockets, also gives a laser more effective range. Maintaining the safety of friendly forces and civilian air traffic in areas protected by laser weapons will be a challenge.
Laser Phalanx: Updates and Developments
Jan 30/09: White Sands Missile Range in New Mexico state continues to test a solid-state laser version of the Phalanx weapons system. The laser has proven capable of “rapidly” penetrating armor plating even when not at full power, and the next step is to test the system on mortar rounds.
The exact time required for burn-through or detonation of incoming rounds is a very important number. The longer an exact focus must be maintained on a rocket or mortar round, the less effective the system will be. US Army release.
July 14/08: Aviation Week writes:
“Two years ago, Raytheon performed a ground test in which two 60 mm mortar rounds were destroyed at 500 m range using an off-the-shelf commercial fiber laser – a 20 kW unit of the type used for welding and other industrial processes. This has now led to the prototype Laser Air Defense System (LADS), combining a 50 kW fiber laser and a beam director attached to a Phalanx gun mount. “
Sept 11/07: Jane’s reports from the British DSEi exhibition that Raytheon is working on a Phalanx variant that can fire lasers.
Sept 1/07: Raytheon announces successful tests of a prototype Laser Area Defense System (LADS) combining the Phalanx radar guided gun system with a solid-state laser. The LADS demonstration used a proven, existing, off-the-shelf solid-state laser, coupled with commercially available optics technology.
During 3 tests performed over the past 6 months, the prototype system successfully detonated 60mm mortars at a range greater than 550 yards. The release does not mention whether the mortars were stationary or in flight. Defense Update.
- DID FOCUS Article – Phalanx CIWS: The Last Defense, On Ship and Ashore