Ballistic Missile Defense is tricky. It requires lots of radar power and plenty of missiles. Right now, you can use your Aegis-equipped ships like the Arleigh Burke-class for the job. But those weren’t designed for the role, and the current state of the art SPY-6 radar is as big as you can fit on one. That is still not ideal for BMD work. Could we do better? Could we make a big air/missile defense ship, preferably on an existing, proven hull? Huntingon-Ingalls has some thoughts on the matter. They currently make the excellent San Antonio-class amphibious transport dock, and think it would be a great candidate for conversion. Let’s look at their proposal.
The San Antonio-class is a large, modern ship for amphibious operations. They are 684 feet long, 105 feet wide, and displace 25,300 tons. They have a large helipad aft for operating MV-22s and have a well deck to launch and recover landing craft or amphibious vehicles like the LCAC. They’re currently in production too. At present, armament is limited to two RIM-116 launchers and two 30mm cannons. They also have provision for a 16-cell Mk 41 suite, but are not fitted with those at present.
HII’s proposed conversion ditches the well deck and and sports a redesigned superstructure capable of mounting four 25’x35′ (WxH) S-Band AESA arrays for better search and discrimination of ballistic missile targets. Four X-Band Arrays would be fitted above the S-Band arrays for tracking and fire control. The large hull of the San Antonios allows the BMD variant to carry no fewer than 288 Mk. 41 launch tubes.
The large hull of the San Antonios allows for plenty of extra power generation and cooling equipment, so that won’t be a problem. The large hull also allows for a higher radar mount without compromising stability. One currently noteworthy limitation is that the San Antonio-class LPDs are only capable of about 22 knots. For the role it’s designed for, that’s not a huge limitation, but they’d slow a task force down if included in one. And the number of tubes would make them tempting to include in a task force.
Finally, let’s talk cost. To the good is that the San Antonio-class production line is hot. An existing hull is no small savings. On the down side, a fancy Aegis-type suite plus big radar that isn’t going to be cheap, and I know of no appropriately-sized radar offhand that would do the job. Radar development isn’t cheap. Overall, I’d say it’s a good idea if you’re really dedicated to BMD, but without actual price numbers, I can’t really give it a great thumbs up/thumbs down. My gut is that it’s a bit too expensive for what it is, given current budget priorities.
Perhaps if just BMD was the job, you could park one out in the ocean – have it surrounded by UUV’s doing ASW+alert helo’s to drop torps and just shoot at BMs. But having that many VLS slots would make the joint force commander salivate… hence creep…
In theory Raytheon’s AMDR is scale-able to achieve the range/power/sensitivity required to meet a BMD requirement:
I also recall seeing a version with pedestal mounted single radars ala Cobra King (http://www.dote.osd.mil/pub/reports/fy2014/pdf/navy/2014cobraking.pdf & https://www.raytheon.com/capabilities/products/cjr)
Wikipedia is saying that an SM-3 was 18.4M per round (FY18 #s)… a magazine of a mere 54.3 SM-3’s would be a billion USD.
Who am I kidding, that thing would be the #1 target until the CVAW got into range…