【Military Subplane】Author: Taibai
The United States "Harpoon" missile, which has remained unchanged for 10,000 years, finally cannot escape the fate of being replaced this time. Not long ago, United States officially started the "RIMPAC Military Exercise" in 2024. During this period, the Alli·-Burke-class guided-missile destroyer DDG-62 Fitzgerald went to Hawaii to participate in live-fire exercises, and launched a naval strike missile NSM instead of the RGM-84 Harpoon missile, which apparently has successfully formed a combat force. What are the characteristics of the NSM missile? What is so special about the Harpoon compared to the past?
▲ "Harpoon" anti-ship missile, picture source: Internet
Let's talk about the research and development unit first, United States did not choose to work independently when developing the NSM missile, but let the "Raytheon" company cooperate with the "Kongsberg" company in Norway to develop it. According to publicly available data, the two companies are able to produce about 120 pieces per year in partnership. But this is a situation with full firepower, which requires the two production lines of the "Kongsberg" company to run at full capacity, even in three shifts. Under normal circumstances, it can be produced at a rate of up to several tens per year. For example, in the next fiscal year of 2025, the United States will only receive about 15 NSMs. However, the United States has decided to invest in Australia and reopen a new production line, which will increase production speed.
▲NSM "Naval Strike" anti-ship missile, picture source: Internet
The NSM was planned to be installed on littoral combat ships and destroyers of the Arleigh ·Burke-class destroyers to replace the 10,000-year-old Harpoon. The Marine Corps also needs NSM on its side, because in the past two years, the Marine Corps has been soaring on the road of transformation. United States is determined to let the Marine Corps "do the whole job" and no longer engage in full-time amphibious landings as in the past. This time, it is necessary to seize the island, defend the island, intersperse, land, control the air, and control the sea, and build an all-round combat capability. It is necessary to streamline the organizational structure and update weapons and equipment. In the future, the United States Marine Corps will make every effort to realize the "expeditionary forward base" combat style, and fight deep into the defense line of the opponent's tactical ballistic missiles. In actual combat, it took control of the islands and reefs by surprise and cooperated with large forces to complete the struggle for sea supremacy. The NSM happens to be an important part of the Marine Corps' weapons and equipment change program. Someone is curious, the Marine Corps does not even have warships, how can it be equipped with such missiles?
That's what makes NSM unique. In the Marine Corps, the NSM is used on land, and it is launched through the NMESIS system. To put it simply, it is a tactical vehicle carrying an NSM anti-ship missile. The CH-54E or V-22 will pull the NMESIS to the designated islands and reefs, and quickly deploy to blockade the surrounding waters and strike the corresponding targets. Back in 2023, the California United States Marine Corps has already tried the power of the NMESIS system. Each NMESIS tactical vehicle can carry two NSMs. Even if you don't go to sea, you don't have warships, you have anti-ship capabilities on land. So if you really want to talk about it, in the future, the Marine Corps will be equipped with this missile even earlier than the Navy.
▲NMESIS system, image source: Internet
Performance-wise, the NSM is quite okay. It has a range of 180 km for the base model and 260 km for the extended-range version. Of course, this range has a lot to do with the flight mode. If the flight mode of the NSM adopts the full ultra-low sea-skimming flight mode, which is commonly known as the 3-low mode of the early, middle and terminal stages, it can avoid being detected by radar to the greatest extent, and the range will naturally not go up due to the high air resistance. However, if the high-altitude mode of initial climb, mid-term altitude maintenance, and finally dive descent is adopted, the theoretical range can exceed 500 kilometers.
In terms of manufacturing process and materials, the shell material of the NSM missile uses a large number of composite materials, and the stealth coating and absorbing materials are applied, which greatly reduces the radar reflection cross-sectional area (RCS) compared with the traditional anti-ship missile. And that's not all, stealth is one of NSM's great features, and its shape adopts a special hexagonal prism shape, which is a special design. In terms of guidance mode, the NSM uses almost all the latest and most advanced combinations, and all useful terrain matching, GPS, and traditional inertial guidance are used. But the funny thing is that the NSM actually did not use the terminal active radar seeker, which is obviously a bit non-mainstream. Looking at the mainstream anti-ship missiles around the world, France's "Exocet", United States' "Harpoon", Ukraine's "Neptune", don't they all have terminal radar guidance? Why did United States abandon this technology?
▲NSM "Naval Strike" anti-ship missile, picture source: Internet
Don't worry, the answer lies in stealth, and United States wants to achieve extreme stealth on the NSM. The active radar seeker actively fires radars at the end to look for the enemy, however, conversely, this also provides a signal for the air defense equipment searching for it. To defend against this type of anti-ship missile, the use of jamming chaff or the activation of search radars can have a considerable probability of successful jamming and interception. United States installed an infrared seeker on the NSM, which has the advantage of receiving information completely passively. First, it is difficult to be jammed, and second, it is difficult to be detected and countered by the opponent's radar. But there are also disadvantages, for many warships with very good infrared signal processing, it is a question whether they can find each other. Therefore, this is a technical contest between the ship's infrared stealth performance technology and the sensitivity of infrared detection equipment. In addition, in extreme weather, such as fog, the performance of the infrared seeker may be greatly reduced.
The NSM has more than one seeker, it also has a radio-frequency passive seeker. The principle is similar to that of a radar wave tracking device installed on an anti-radiation missile, which can locate the source of the radar wave emitted. Therefore, the NSM will have considerable strike accuracy when the opposing warship uses fire control radar or search radar. Once a certain warship turns on the search or fire control radar when the NSM is coming, it is simply playing into the trap. In extreme cases, the NSM can also be used as a cruise missile. The NSM is also interesting in flight, its main wing is two horizontal in the shape of a line, and the wings have a certain backsweep angle. The tail is X-shaped, with the NSM air intake facing upwards at the beginning of the launch, and then turning the direction of the air intakes facing downward when entering the cruise phase.
▲NSM "Naval Strike" anti-ship missile, picture source: Internet
The NSM is a little smaller in size than the Harpoon, with a length of only 3.5 meters. The long-range version (shipborne version) is about 3.96 meters long after the booster is installed. The most commonly used Harpoon missile in the U.S. military today is 3.8 meters in its base version, and its booster version (shipboard version) is about 4.6 meters. The total weight of the Harpoon missile is about 0.69 tons, and the NSM is only 0.4 tons. The range of the two is almost the same, so it is certain that the mass of the NSM's warhead has been cut, and it is actually expected to be only about 120 kg. The size of the NSM is so tightly controlled because the internal bomb bay of the F-35 fighter can only accommodate missiles under 3.8 meters at most. This criterion must be met if the NSM is to fit into the F-35 bomb bay. The NSM clearly meets the criteria, and the F-35 will be able to fill the magazine with two at a time in the future.
The NSM is also a standard subsonic missile, with a maximum speed of Mach 0.95. Interestingly, its engine is actually a turbofan engine produced in France. Because compared to the turbofan engine produced by the United States, this one is lighter and has a higher proportion of composite materials. In the history of the development of anti-ship missiles, the debate about whether supersonic or subsonic is better has been going on for many years, and there are even cases of developing sub-supersonic combined anti-ship missiles.
▲NSM "Naval Strike" anti-ship missile, picture source: Internet
Generally speaking, Russia attaches more importance to the flight speed of missiles, which has the advantage of giving the other side less time to react, and the disadvantage is that the range is short, unless a high-throw trajectory is used. But in this case, it is easy to be detected. Although the flight speed of subsonic anti-ship missiles is slow, they are superior to their small size and can fly all over the sea. As long as the stealth is done well, the probability of successful penetration is much higher than that of supersonic speed alone. Russia heavy supersonic anti-ship missiles, and United States heavy stealth subsonic anti-ship missiles, NSM is still developing according to the traditional ideas of United States.
United States has the world's leading anti-missile capabilities on land and sea, so its own anti-ship missiles pursue a stable and accurate ruthlessness. Flying fast may not be a priority. All in all, the NSM has been carefully designed to completely replace the United States 10,000-year-old Harpoon in the future, and will play an important role in the Navy, Air Force, and Marine Corps. In conjunction with the United States's new qualitative combat concept, the NSM has a high probability of participating in high-end conflicts. We should study it in detail, guard against it as early as possible, and never take the enemy lightly.