The US warship’s destruction of an incoming Houthi missile in the Red Sea this week marks the first use in this conflict of an advanced weapons system also called the “last line of defense” of the US Navy.

As CNN reports, the Phalanx Close-In Weapon System (CWIS) was used by the Navy destroyer USS Gravely on Tuesday night against what US officials said was a cruise missile that came within 1 mile of the ship – and thus seconds before impact with the US vessel.

The Phalanx automated system has Gatling guns that they can launch up to 4,500 20mm projectiles per minute, having the ability to hit projectiles or other targets at extremely close range.

“The Phalanx weapon system is a rapid-fire weaponcomputer-controlled, radar-guided missile capable of defeating anti-ship missiles and other near-land and sea threats”manufacturer Raytheon states in an article on its website titled, “Last Line of Defense.”

US warships have successfully dealt with dozens before Houthi missile attacks using longer-range defense systems such as the Standard SM-2, Standard SM-6 and Evolved Sea Sparrow missiles, analysts say. These defensive missiles engage their targets at ranges of about 12 kilometers, or more.

But at night on Tuesday this did not happen for undisclosed reasons.

Tom Karako, director of the Missile Defense Program at the Center for Strategic and International Studies, said it was “alarming” that the Houthi missile came so close to a US warship.

For his part, analyst Carl Schuster, a former US Navy captain, commented that the Houthi missile, which had developed a speed of about 965 km per hour, was about 4 seconds from hitting the US warship when destroyed by 2 to 3 second Phalanx machine gun fire.

He noted that destroying an incoming missile at a range of 1 mile does not necessarily prevent warships from being hit by debris.

“Missiles do not vaporize when destroyed, send thousands of fragments and components from the missile frame,” Shuster explained. “The good news is that lighter components slow down quickly, but large pieces can be launched up to 500 meters.”

The closer the incoming missile is when it is destroyed, the greater the danger to the target vesselwith larger fragments capable of penetrating unarmored parts of the hull from about 200 meters Shuster commented.

In the event of a subsonic cruise missile like the one the USS Gravely encountered on Tuesday, “depending on whether the warhead explodes, the size of the fragments, the angle of flight of the missile and its height at the time of destructionabout 2% of the debris can reach the ship” he said.

Up to 70% of missile fragments traveling at a higher speed, such as hypersonic cruise missiles or ballistic missiles, would likely hit a warship after being engaged by the Phalanx.

Phalanx has a limited height rangetherefore it can not even be able to engage ballistic missiles that strike a warship from above, the analyst added.

Even with these limitations the system is valuable to the US Navy.

Since its introduction in 1980, it is now installed on all US Navy surface ships and at least 24 US allies use itaccording to Raytheon, which notes that the ground version has also been tested in combat in the past.

Whether it will be used further in the current hostilities in the Red Sea remains to be seen. But the Iran-backed Houthis show no signs of abating in their attacks on merchant ships and warships in the waters around their base in Yemen, which they claim are retaliation against Israel for its war in Gaza.

A day after the Gravely attack, the US Central Command reported that another US destroyer, the USS Carney, had shot down incoming anti-ship missiles and drones. And on Thursday, US forces shot down a Houthi drone over the Gulf of Aden and destroyed a surface drone in the Red Sea, it said.

Alongside, two ballistic missiles fired from Houthi-controlled areas of Yemen miss targets in Red Seasaid American Central Command.