Neptune missiles sank the Russian flagship Moskva. Here's all we know about the weapon

A senior U.S. defense official has confirmed to NPR that it was indeed the Ukrainian Neptune missiles that were responsible for the sinking of the Russian flagship, Moskva. 

Last week, we had reported the Ukrainian claim that its Neptune missiles had struck the Russian Slava-class guided-missile cruiser, twice. Russian authorities, however, reported that a fire had broken onboard which also caused an explosion of ammunition on the ship, prompting an evacuation of the crew. The carrier reportedly sank while being towed away and now sits on the sea bed at a location that has not been disclosed so far. 

The Neptune Rocket System

Named after the Roman God of the Seas, the Neptune 360 ST is a land-based rocket system equipped with anti-ship missiles. As we had reported earlier, the rocket system has a Soviet origin and was originally developed in the early 1970s. It took decades of work for the rocket to be deployed even in the Russian Federation as the Kh-35 missiles, with a range of about 75 miles (120 km) in 2003. 

Ukraine, however, began developing the system, only in 2013, and even after five years of development by the state-owned Luch Design Bureau (LDB), the anti-ship missiles had a range of 62 miles (100 km), just like the Kh-35. During tests carried out in the following years, the range of the missiles increased significantly, with the LDB claiming a range of 186 miles (300 km). 

The anti-ship missiles can be fired at a wide range of ships such as destroyer frigates, corvettes, tank landing ships, or in the recent case, cruisers, from a truck equipped with four launchers.  Once moved into position, not more than 15 miles (25 km), from the coastline, the rocket system is ready to launch in less than 15 minutes. It can fire up to 16 rockets in a salvo with a maximum delay of five seconds between each launch, an LDB brochure claims. Upon firing, the truck can move out of its position to take up a new one and can move with a top speed of 43 mph (70 kph) on highways. 

The Neptune rockets, themselves, are slightly over 16 inches (420 mm) in diameter and weigh over 1,900 pounds (870 kg). By weight comparison, the rocket is slightly lighter than the U.S. anti-ship missile, Harpoon, and carries a 330-pound (150 kg) explosive warhead. 

To evade air-defense measures that modern warships are equipped with, the Neptune rockets fly barely 10-30 feet above the water surface. Not only does this help the weapon stay below the enemy's radar but also helps it cover its distance quicker, giving the adversary lesser time to react if the rocket is detected in flight.

It is unclear whether the Moskva failed to detect the Neptune completely or its defenses did not work against the rocket system, The New York Times reported. Warships often try and stay out of the range of such mobile weapon systems while at sea. We do not know why or how the Moskva was allowed to sail so close to the Ukrainian coastline.