With the purchase of the Air Warfare Destroyers (AWD) complete with the Aegis weapons system, ADM thought it might be time to have a look at what these ships can do in the ballistic missile defence (BMD) space. What can we achieve and what do we want to do?
Missile defence is a system, weapon, or technology involved in the detection, tracking, interception, and destruction of attacking missiles. Originally conceived as a defence against nuclear-armed intercontinental ballistic missiles (ICBMs), its application has broadened to include shorter-ranged non-nuclear tactical and theatre missiles. For reference, the US missile defence program under the Missile Defence Agency (MDA) is the most well known and controversial of BMD programs globally. It’s hard to talk BMD in a meaningful way without having some history and some technical background. First, the history side of the equation.
In the late 1990s, and early 2000s, the issue of defence against ballistic missiles became more prominent with the new Bush Administration. In 2002, President George W. Bush withdrew the US from the Anti-Ballistic Missile Treaty, allowing further development and testing of ABMs under the MDA, and allowing for deployment of interceptor vehicles beyond the single site allowed under the treaty.
When BMD became an issue in the US during this period, it was the Army that took the lead in the development efforts. The USN was late to the game but was able to contribute under the Aegis program which gave equipped ships the sensor and shoot ability similar to those afforded by land based systems such as the THAAD system (Terminal High Altitude Area Defense).
“We primarily focused initially on the exoatmospheric weapon with the Standard Missile 3 (SM-3) and then we followed that with an endoatmospheric weapon with the SM-6,” Brad Hicks, RADM, USN, ret. Vice President for Integrated Warfare Sensors and Systems and former Aegis BMD Director explained to ADM.
Missile defence can take place either inside (endoatmospheric) or outside (exoatmospheric) the Earth's atmosphere. The trajectory of most ballistic missiles takes them inside and outside the Earth's atmosphere, and they can be intercepted either place. There are advantages and disadvantages to either intercept technique.
Some missiles such as THAAD can intercept both inside and outside the Earth's atmosphere, giving two intercept opportunities. Endoatmospheric anti-ballistic missiles are usually shorter ranged such as the American MIM-104 Patriot. The payoffs include a physically smaller/lighter missile which are easier to move and deploy and endoatmospheric intercept means balloon-type decoys won't work against them. But they have a limited range and defended area plus a limited decision and tracking time for the incoming warhead.
Exoatmospheric anti-ballistic missiles are usually longer ranged like the Ground-Based Midcourse Defense. This system allows for more decision and tracking time and fewer missiles required for defence of a larger area. However, the system requires larger/heavier missiles which are more difficult to transport and emplace than smaller missiles and the system must also be able to handle decoys effectively.
“So we generally describe ballistic missile defence as exoatmospheric and endoatmospheric. Exoatmospheric is above the earth’s atmosphere in space,” Hicks continued. “Exoatmoshere is the preferred area to intercept those ballistic missiles that actually go into outer space. The rationale there, if you can intercept a threat in space and you hit it then the ability of the debris, particularly if it’s a weapon of mass destruction, will burn off in the earth’s atmosphere, much like the satellite shoot down that occurred back in 2008.
“The US designed the ground based interceptors originally to handle long range, high speed ballistic missiles that are either what we call intercontinental or extremely long range ballistic missile threats. The Aegis system was designed to intercept those weapons that are medium range to short range or at the low end of the line for ballistic missile threats. That was the SM-3 family originally. And then for those missiles that are low exoatmospheric, right above the earth’s atmosphere and in the earth’s atmosphere the US THAAD system was developed.”
The USN and wider US defence community has had over a decade of testing weapons and concepts in this space thanks to systems like Aegis, THAAD, Ground-Based Midcourse Defense (GMD), PATRIOT Advanced Capability-3 (PAC-3) and Medium Extended Air Defense System (MEADS), a co-developmental program of the US Department of Defense, Germany and Italy.
With an Aegis equipped ship, the RAN and wider ADF are now positioned to play a meaningful role in the BMD space, either individually or as part of a coalition. But how much they choose to exploit the technology available to them is choice for government and the top levels of Defence.
“The way I used to describe sea based missile defence is like going to the movies,” Hicks explained to ADM. “If you want to go to a nice movie you’ve got to pay for a ticket and there’s a price of admission to do this mission. One, the first entry ticket into the theatre is to have a sensor, a radar or a data link to provide you the information necessary to come up with a solution. Then you can decide upon which means you want to engage a target. So if you don’t have the sensor or the data link to provide you the information to make a decision then you can’t have the price of admission.
“The next step is what I call “I want to sit in the middle of the theatre in the centre seat with nobody sitting in front of me that can block my view” and that’s what I call having a weapon. If you have a weapon like an SM-3 or an SM-6 missile then you can sit there because you can take the information you have off your radar or a data link and launch a missile to engage the ballistic missile.
“That also requires you to have a launcher that can hold the missile. That’s not an insignificant event. If you fire a missile like an SM-3 or SM-6 it’s a very high energy missile that has a lot of heat so you have to have a robust launcher that can fire that missile. Most launchers that can’t do that. Today the MK 41 Vertical Launching System (VLS) is the only sea based system that can handle these weapons.”
The SM-3 family of missiles is designed for exoatmospheric intercepts; SM-6 is a dual-purpose missile that’s sea launched that can execute endoatmospheric BMD missions as well as long range air defence engagements against manned aircraft and cruise missiles.. Each AWD’s main weapon is a 48-cell Mark 41 Vertical Launch System. The cells are capable of firing the SM-2 anti-aircraft missile or the quad-packed Evolved Sea Sparrow (ESSM) point-defence missile. Investigation into the firing capability of the SM-6 has been undertaken.
“So the last thing I’d say you need is the theatre has to have an audio system or you can see the movie but you can’t listen to it; that’s the command and control system that controls the sensor to the missile. If you have that then you have it together.
“I would describe the audio system as the Aegis weapons system and the data link. I would describe the launcher as giving me the seat and I would describe the sensor as allowing me to get into the theatre. If you don’t have those ingredients then you can’t play. In the case of what Australia’s purchased with Air Warfare Destroyer, they have purchased the pieces necessary to do the mission. The only issue is are they watching the right movie?”
Australia would have the capability to establish a BMD shield around the northern approach of Australia with the AWD fleet. This could of course be supplemented with land-based sites that could be online when AWDs are not on station. But does it want to? There are opportunities and costs associated with any BMD capability that Australia chooses to exercise.
It will be interesting to see what Australia chooses to do in this area given the last White Paper that raised the issue of BMD. What will the next White Paper bring?
This article first appeared in Australian Defence Magazine VOL.23 No.3, March 2015