Propelling Missiles into the Future

A lot of today’s anti-air missile systems have some pretty serious drawbacks: They cannot reach high altitudes. Range is limited. And targets that are fast and maneuverable, such as fighter jets or missiles, can be very difficult to hit. However, a new generation of Ramjet-powered anti-air missiles could spell the end of all these shortcomings.

Frank Møller, Nammo’s VP for strategy and business development. Photo: Nammo

– I think there’s a race going on internationally. Rocket technology has improved. Cruise missiles are getting longer ranges, better sensors, improved accuracy, and the cost has gone down. But a reaction is coming: Armed forces everywhere are scrambling to improve their missile defenses.

Frank Møller, Nammo’s VP for strategy and business development, has more than 30 years of experience with missiles and rocket motors. Now, he feels the business is going through some of the biggest changes ever.

Countries like Russia have invested heavily in better, longer range missile systems. High-flying strategic bombers planes, especially bombers like the Tu-160 “Blackjack” with a service ceiling of 52.000 feet, are still in operation. And unmanned, potentially stealthy strike aircraft are a certain part of many future air forces.

An AMRAAM missile as it is fired from a Norwegian NASAMS II launcher in Norway. In the future, systems like these could both get much longer ranges, as well as the ability to reach targets sigificantly higher up. Photo: Martin Mellquist / Norwegian Armed Forces

At the same time, western countries have changed in ways that make them more vulnerable for strikes. Møller believes Norway is a good example:

– Norway has a number of possible targets that would have an extremely high value in a conflict scenario: The F-35 aircraft (most of them stationed in one base at Ørland), the North Sea oil rigs, our major cities, important infrastructure, and so on. We are more dependent on these than before, and need to protect them. And I think that’s a development that mirrors what we see in other countries, Møller says.

The Wasp-class amphibious assault ship USS Bonhomme Richard (LHD 6) fires a Sea Sparrow missile during a missile exercise. Photo: U.S. Navy / Mass Communication Specialist 2nd Class Raymond D. Diaz III

The rocket motor veteran feels investing in advanced air defense is an obvious counter. Luckily, technology has advanced to a point where such defenses can, possibly, be revolutionized.

– We have a situation where several crucial technologies have advanced. Together, they are paving the way for new concepts and defense applications. If one looks at defensive systems, this is quite clear. And it’s the flip side that is happening to missiles with possible offensive uses.

Two to five times the range

Frank Møller and his colleagues at Nammo – one of only four manufacturers of tactical rocket motors in NATO – are working on Ramjet technology for missiles. The concept has been around for decades, but some crucial new improvements – converging with advances in other fields – has finally made it viable. Frank Møller is sure we will see products on the market within a few years.

Erland Ørbekk, Nammo’s VP of technology for aerospace (left) and Frank Møller, Nammo’s VP for strategy and business development (right). The duo is holding a mock-up ramjet missile. Photo: Nammo

– Long range ramjet artillery will likely be on the market within 2-4 years. For missiles, it will take a bit longer, but we are confident that the technology is ready. What we are working on now is more focused on the practical applications and technical solutions.

– Are you sure of that? Are you sure the technology will work?

– Absolutely. And it will be a momentous change.

An F-35 plane releasing an AIM-120 AMRAAM missile. Ramjet technology has the potential to greatly increase the range of such AA missiles. Photo: USAF / Master sgt. Michael Jackson

Range is one of the areas where today’s missiles could be left in the dust. Even regular passenger aircraft cruising at just over 30.000 feet would be out of range for most current air defense systems. This is true for those designed for short to medium range use. They are far smaller and less expensive than longer range systems like Patriot or S300/400. But the main tradeoff is range and the ability to go high.

– The usual solid-propellant rockets have an extremely short range. Most people don’t know that they would not be able to reach even a normal passenger plane, for example. They simply can’t get to that kind of altitude.

Nammo now aims to make the smaller air defense systems every bit as capable as their bigger and more expensive brethren.

Maintainers from the 18th Aircraft Maintenance Squadron loading AIM-9 sidewinder missiles and AIM-120 advanced medium-range air-to-air missiles onto F-15 Eagles at Kadena Air Base, Japan. Photo: U.S. Air Force / Senior Airman Peter Reft

– The next generation will change a lot. Ground-based Ramjet missiles will be able to take out high altitude targets. And if fired from aircraft (an air-to-air missile), they will be able to target even high-speed fighter jets performing last minute evasive manoeuvers, Møller says.

Frank Møller indicates that a Ramjet-powered missile will realistically have two to five times the reach of today’s missiles, while retaining the same size. They will also be more maneuverable and reach much higher – likely as much as 60-70.000 feet.

An Evolved Sea Sparrow missile (ESSM) is launched from the aircraft carrier USS Carl Vinson. Photo: U.S. Navy / Petty Officer 3rd Class Patrick Green

Replacing oxygen with fuel

In a conventional rocket motor, oxygen accounts for 80% of the fuel weight. But a Ramjet instead uses oxygen from the outside air. As a consequence, oxygen can be replaced with fuel – increasing the capacity four or five times. Erland Ørbekk, Nammo’s VP of technology for aerospace, explains that the advantages are great – if a missile can reach high enough speeds.

– In a traditional air breathing motor, you need a compressor, a combustion chamber and a turbine. But in a Ramjet, the oxygen pressure and temperature will be high enough just from reaching a high enough speed (mach 3). A Ramjet missile can have a burn time of up to 300 seconds (5 minutes), and can be throttled up and down, or even turned on and off, Ørbekk says.

– What operational advantages can we expect?

– A Ramjet-powered missile will be superior to a conventional missile in all possible ways. Ground-based Ramjet missiles will be able to take out high altitude targets. And if fired from aircraft, they will be effective against high-speed and highly maneuverable fighter jets at much greater distances than today. We believe they could even be effective against some of the new high speed missiles being introduced outside NATO. If you have a good enough sensor system on the ground, it will be possible for Ramjet-powered missiles to intercept them.

Watch Nammo’s mini documentary about ramjet artillery: