State of the Royal Navy: a roundup - Part 1

Type 45

Some good news from the Type 45s front. All ships appear to have received their Phalanx fit, even HMS Duncan, the last vessel to enter service, which sported them in her recent visit to Oslo for the 200 years of the norwegian navy.
As we have known from MOD words since last year, Harpoon missile fit is also on the way for four of the six ships. It is not exactly clear when the missiles will take their place on board, but the Royal Navy's website itself is confirming that HMS Duncan is going to be the first in class getting the system. Unconfirmed reports suggest that Daring, Dragon and Diamond will be the other three. It remains unclear if the other two ships in the class are going to be cut out entirely, or if they will be fitted with the launchers infrastructure, wiring and software, allowing the missile fit itself to be moved from vessel to vessel to ensure the deployed ships have the capability.
The MOD said that additional equipment would be purchased to enable the integration of Harpoon on Type 45 (in addition to the kit that is recovered from the four decommissioned Type 22 Batch 3 frigates) but it is not clear if it is needed for the four ships, or to prepare the other two.
If all vessels get the infrastructure and system integration, swapping the missile fit from one to another is not going to be an issue; but unfortunately i'm inclined to read it as having two vessels which will flat-out not get the capability.
It is also not clear when the missile fit will appear. HMS Duncan was seen in port last march with a white tent covering what was almost certainly work related to getting the Harpoon infrastructure in; but on her subsequent sorties to sea, she still does not sport the missiles.

HMS Duncan in Portsmouth, back in March, with tarpaulin covering the Harpoon area. It is reasonable to assume she underwent some fitting out related to the missile fit, but the job isn't finished yet. Photo by Chris Argles. Thank you for letting me use the image!

Seen in Oslo in May 2014, HMS Duncan has gained Phalanx, but is still missing Harpoon, in a Royal Navy photo

HMS Defender has made progress towards full capability by receiving her own Phalanx fit and by firing Sea Viper for the first time on May 15.

Those who follow me on Twitter already know that i've been doing my best to track the Anti-Ballistic Missile tests undergone by HMS Daring in her long deployment in the Pacific. A while ago i had concluded, thanks to documents of the US Missile Defense Agency, that she had been part of
Flight Test Operational-01 (FTO-01), a US BMD System operational test executed at the Reagan Test Site/Kwajalein Atoll in the Marshall Islands.
Since then, an interesting Jane's article has confirmed that i was right in my reconstruction of the events. The results of HMS Daring's work with the modified SAMPSON radar have been good enough that the MOD has provided additional funding to continue with the ABM development program. This is a welcome development, even though so far there continues to be no plan for the eventual roll out of ABM capability to the Type 45 fleet, nor any plan to provide the ships with anti-ballistic missiles. 
The new phase of development should culminate in another ABM test in 2015. The target is to better integrate the ABM radar functionality into the ship's combat system, and add better interoperability with US ABM assets by introducing the necessary data link format. 
The 2013 test used an ABM software functionality that was separated from the ship's mission system. This required the effective "shut off" of the normal Anti Air Warfare capability of HMS Daring, which slaved its main radar to the sole ABM task instead. 
The aim for 2015 is to demonstrate an integrated ABM function running alongside the AAW mode. This paves the way for a "full spectrum" air defence and anti ballistic capability comparable to the latest american AEGIS Baseline 9 combat system; an ambitious target. 

In early 2016 the Type 45 fleet will also finally begin to receive the fully integrated Electronic Chart Precise Integrated Navigation System, the key component of the Warship Electronic Chart Display and Information System (WECDIS) navigation capability.
WECDIS is a fleet-wide program which is delivering electronic mapping and navigation to the fleet, including to submarines. 



Type 26 

Although still unconfirmed, according to Jane's the MOD is about to select the BAE MK45 Mod 4 gun as the artillery piece for the Maritime Indirect Fire System program, a branch of the wider Type 26 frigate enterprise. This would mean defeat for the Oto Melara / Babcock team, offering the 127/64 Lightweight, which was earlier seen as the favorite. 
The Lightweight is a more modern artillery piece, offering a much higher rate of fire (over 30 rounds per minute versus 20 plus) and a wholly automated high capacity ammunition magazine. Both BAE and Oto Melara can also offer guided long-range ammunition, respectively the Standard Guided Projectile and the VULCANO ammunition family. These follow very different design phylosophies, with SGP using rocket propulsion to extend the range of a full-width 127mm shell, while VULCANO uses a sabot-discarding, slim dart which exploits aerodynamics to reach long distances, at the expense of a smaller payload. Details of the two guns and of their ammunition is inside an earlier article.

In addition, British Forces News has visited the BAE design centre, and saw the virtual reality 3D design work ongoing for the Type 26 frigate. Observing the design work, a couple of things caught my attention: the new warship is possibly going to have a mission centre aft of the bridge, with windows looking out directly over the sides of the vessel, and possibly even facing aft, to give a greater and more immediate situational awareness. 
These 360° degrees bridges are becoming more common in warship design. The Holland class OPVs use the COBRA (COmmand BRidge Aft) arrangement; while other vessels have similar conceptual solutions, such as the DCNS Androit OPVs, and the still in design PAM multi-role warships for the italian navy.  
There is no way to confirm, at the moment, whether my suspect is correct or not, but windows definitely seems to have appeared aft of the bridge, suggesting a COBRA-like arrangement. 

A long row of new windows has appeared aft of the bridge, right beneath the sensors mast. The funnel mast also seems to have been redesigned and split into two masts of differing heights. 

The COBRA used on the Holland OPVs offers a mission control centre right behind the bridge. Armored windows ensure direct view of the bridge itself (see photo) as well as of the sides of the vessel. 

Panoramic view of the COBRA centre, with windows giving a view on the bridge and on the sides of the vessel. Might the Type 26 gain a similar arrangement?

The bridge itself seems virtually identical to the Type 45's one. The images shown do not allow me to say whether there are windows between the bridge and the supposed mission control area aft of it, like in the COBRA arrangement.

The graphic of the design being refined by BAE also suggests that the funnel mast has changed, splitting into two masts of different height. 

It will be interesting to see how the mast area is eventually reconfigured, and if it has any impact on the disposition of the pole masts and related communications equipment; on sensors and eventually even on weapons capability. The aft CAMM launchers apparently are still there, in the low mast aft of the funnel area, but maybe the new arrangement opens up space for anti-ship missile launchers?

The monolithic funnel mast as last showcased, at DSEI last year, with the CAMM missile cells. The more recent graphic suggests a split mast, with the aft half rising higher up (apparently almost to the same height of the SCOT 5 satcom radomes on the mast). Might we be looking at a new base for sensors or a relocated pole mast? 

In the design as last showcased, the Type 26 appears to have no space available for the fitting of the traditional quadruple missile launchers employed by Harpoon, NSM, Exocet, Teseo and other missiles. This could be seen as both a weakness in regard to exportability (those missile systems remain the most prevalent on the market) and a risk to the Royal Nayy's own anti-ship missile capability in the future, as there still isn't a truly defined plan to acquire a vertical launch weapon to replace the old Harpoon. The redesign could also address this aspect, possibly.

The Type 26 program should get the go ahead by the end of the year, probably with the aim to sign a contract for the first 8 frigates, leaving the other five for another day. 
Among the hurdles to be overcome, we have to include the referendum that will decide the future of Scotland. Until the result is known, the shipbuilding programs will be somewhat restrained, including the final go away for the BAE's plan of redevelopment of the shipyards on the Clyde. The preferred option sees a 200 million upgrade to the Scotstoun facilities, to create a single, fully capable yard, with the closure of Govan and the transfer of the manpower. There is also, formally, an alternative that sees both shipyard retained, and given a more limited uplift. The ship building process split on two sites, however, is less efficient. Finally, there's the "doomsday" scenario that sees both these ideas junked, in the quest for uplifting the capacity of one of the shipyards south of the border instead, in the case Scotland walks away. Something i dearly hope does not happen, as it would bring nothing good, to no one.

 




 
Submarines

HMS Tireless is about to leave service, after having its life extended (it was planned it would decommission already last year) and after completing another long deployment which gained great media visibility when it was sent searching for the lost MH370 airplane. 
HMS Artful, the third of the Astute class submarines, has finally entered the water, many months later than originally planned. In general, the delays of the Astute class sure have kept the Royal Navy worried for a long time, and caused quite a bit of pressure. 

Artful is the first in class fitted with the Common Combat System (CCS), which uses common consoles, electronics cabinets, and commercial off-the-shelf hardware and software to create a shared computer environment. The CCS is the result of a Royal Navy initiative to streamline and future proof the fleet's combat systems, to develop more open system architectures that are more cost-effective to maintain and easier to update.

The next submarine, Audacious, will be launched incorporating further improvements. such as the Naval Extremely / Super High Frequency Satcom terminal (NEST) and a variety of enhancements grouped under the Astute Capability Sustainment Programme. 

NEST has seen the installation of a new antenna and related equipment at the Colerne satellite ground station in Wiltshire. This new equipment enables Super High Frequency communications using the british Skynet 5 satellite constellation, or Advanced Extremely High Frequency communications using the american AEHF satellite constellation.

The Rafael TORBUSTER advanced countermeasures system, which uses decoy which combine seduction and hard-kill capability, has been proposed as part of the Astute CSP by a team made up by BAE, Babcock and Rafael, but we might never get told whether it is being installed or not.When it comes to submarines, information is always sparse. 

Full new Communication and Radar Electronic Support Measures (CESM and RESM) capability has also been funded as baseline fit from Boat 4 onwards. 

The Spearfish heavyweight torpedo upgrade programme is also underway. The program includes the replacement of the two different fuels employed by the torpedo with a single one; the replacement of the warhead with a new one, compliant with Insensitive Munition rules; the digitalisation of the weapon; and a new fiber optic guide fibre replacing the current copper/cadmium wire, removing the delays in communication between the torpedo and the submarine. The end result will be almost a new weapon, with much greater capability and greater safety. Again, the details on the state of the Spearfish upgrade program are under wraps, but there has been a delay in the signature of contracts for the next phase of the work, which means delays. 

Looking ahead, to the delivery of the next Astutes and further away to the Successor SSBNs, the MOD and BAE have given green light to a 300 million project for the upgrade of the shipyard facilities in Barrow.  

The future could also include ultra-accurate navigation, completely independent from vulnerable GPS signals, thanks to a science development project ongoing for quantum positioning technology.

New OPVs

The contract for the delivery of three new OPVs should be signed soon. Little is known about these vessels, other than they will be derived from the 90m OPV design mostly known as Amazonas class, due to the ships of this type having been purchased by Brazil.
The new OPVs will have a flight deck compatible with the Merlin helicopter. What's not at all clear is the fate of the OPVs of the royal navy, as shortage of money and manpower might make these new vessels the replacements for the still young River-class. Even though the MOD has just purchased, for 39 millions, these vessels which have been operated for years under a leasing agreement.

I've already expressed my opinion that such a decision would be an inexcusable waste of money, time and good ships. While i fully understand the rationale of keeping the shipyards working to bridge the gap between the carriers and the Type 26 frigates, in order to keep the production line "hot" and in order to retain manpower and expertis, i think that withdrawing the Rivers would be a grave mistake.
The new OPVs will be extremely welcome and useful if they are kept in addition to the Rivers, not in their place.
The Rivers will be barely around 14 years old when the first new ship is delivered, in 2017, and the Royal Navy has a clear need for deployable hulls. The new OPVs, with their greater sizes and capability (including helicopter) can and should be used away from home, to relieve the frigates of some of their tasks (Caribbean, but also counter-piracy, for example), while the River continue to do what they have done well for years.

The government has right in these days published its Maritime Security strategy. The document, while being of some interest, hardly deserves the praise it received from several commenters. Moreover, the supposed "strategy" is written out in a deliberately ambivalent, vague way, especially when it comes to the new OPVs: mentioned several times in the document, they are described as a "further improvement" to the UK's maritime security capability, but not once there is a clear statement of their fate, and that of the Rivers. The official line is that the decision is left for the next SDSR. Of course.
The document has been written in such a way to allow the government to bin the Rivers and still describe the situation as an "improvement" because of the greater capabilities of the new vessels, regardless of the fact that, observing historical trends in the use of the Rivers, it is safe to say that such additional capabilities would be hardly be needed, and will only sparsely be exploited.

The hope can only be that, thanks to the very modest cost in money and manpower, the OPVs gain points in the SDSR.


Carrier Enabled Power Projection 

With HMS Queen Elizabeth to be named by the queen on July 4, and the manufacture of HMS Prince of Wales currently significantly ahead of schedule, the building of the carriers is progressing well. The program costs have been re-agreed, hopefully for the last time, and the MOD is planning ahead to reach the SDSR 2015 with a full set of options for the way ahead for CEPP. In particular, the MOD is coming up with plans for the second carrier, as well as for the vital MARS Fleet Solid Support capability, which has to deliver the ships which will replace the Fort class vessels in the 2020s.

CEPP also includes a dependency program for the delivery of amphibious capability via the carriers, a requirement made unescapable by the impossibility to fund a dedicate replacement for HMS Ocean.
The carrier includes design features such as wide assault routes and accommodation for a 250-strong reinforced Marines company, which can be expanded further depending on the composition of the air wing. Less jets means more Marines and helicopters. Deck manoeuvers, and even deck layout, are being thought out to accommodate the amphibious requirement, including concurrent jet and helicopter operations. It is possible that the deck layout selected will include 10 spots for medium helicopters operations.

In a very welcome move, the MOD has also moved to substantially close the unacceptable gap in AEW coverage, by keeping 7 Sea King ASaC in service all the way to 2018, and by speeding up the CROWSNEST program by 18 months, with the aim of having the first AEW capability on Merlin HM2 in 2018, in time to nearly completely avoid the gap.


Fleet Air Arm  

As said above, even as the Sea Kings of all other variants are withdrawn from service in 2016 as planned, 7 MK7 ASaC will be kept flying with 849 NAS up into the second half of 2018. By then, it is hoped that the initial capability of the CROWSNEST radar package for the Merlin HM2 will have been achieved, substantially closing the dangerous, unacceptable AEW gap which would have lasted for a good four years or more according to the initial plan.

As a way to prepare to the return of fixed wing naval aviation when 809 NAS will reform on F-35B, the Fleet Air Arm has taken back control of Fleet Requirements and Air Direction Unit (FRADU) from private contractor Serco. The squadron, equipped with 14 Hawk T1s, was recommissioned in Culdrose on June 6, 2013 as 736 NAS.

736 NAS is an extremely busy squadron, which has inherited all the tasks of FRADU.
Its role is serving as Maritime Aggressor Squadron, and is best known for providing threat simulation to warships conducting OST in the South Coast Exercise Areas. The Hawks, with the help of Falcon 20 aircraft loaded with towed targets and EW pods, provided by the contractor Cobham, train the royal navy in defence against air attacks.
736 NAS also delivers intercept training to the RN School of Fighter Control at Yeovilton, Close Air Support (CAS) training to 3 Cdo Bde as well as Army units, and Affiliation training to Rotary Wing Squadrons at both Culdrose and Yeovilton. It is a good place, in other words, for the Royal Navy pilots to work their way up to the rebirth of naval fixed wing aviation. 

FRADU in action, with Hawk and Falcon 20 jets, the latters equipped with a variety of EW system pods

The Fleet Air Arm has finalised its plan for the transition from Lynx MK8 to Wildcat HMA2, which will include the return of 825 NAS, which will reform out of the merge of 700W Nas and 702 NAS as the training squadron moves on from Lynx to Wildcat. 

825 NAS will be commissioned in september this year, to deliver training for the Wildcat and to form the first four ship flights. 
815 NAS will begin to convert to Wildcat from the second half of 2015. The transition will take time, and Lynx helicopters will continue to provide their service all the way up to their OSD, planned for 31 March 2017. 
815 NAS, once fully converted, will line 12 single-manned Flights at readiness for deployed operations worldwide and 2 double-manned MCT Flights at very high readiness in the UK.

One problem remains for Wildcat: the big delay in the FASGW program which has to deliver the two missiles it will use in its maritime attack role. They are not expected to be available before 2020, which means a big gap is taking shape as the Lynx force draws down and, with the Lynx, the Sea Skua missile does progressively vanish as well. 


Separately, in the Commando Helicopter Force, 847 NAS is converting to Wildcat as well, but the squadron uses the Wildcat AH1, the same variant employed by the Army, in support of the Royal Marines. 847 NAS will be the first operational Wildcat squadron.

Another transition is due to take place in the CHF, with the Sea King HC4 being replaced by the ex-RAF Merlin HC3/3A, later to become HC4 as they are fully upgraded and navalised.
While Fleet Air Arm crews have been training for a long time and the transfer of the helicopters to the Navy is underway, the first bit of naval capability will only arrive between late 2015 and early 2016, as the first 7 Merlin are delivered in interim, Phase 1 navalisation including folding rotor head, lash down points and other minor changes. These helicopters (HC3i) will bridge the gap forming as the Sea King HC4 bows out of service, replaced by helicopters which, in their current form, are unsuitable for shipboard operations.

848 NAS, the training unit for Sea King HC4, stood down in december 2013 after delivering the last training course. 846 disbanded in March 2014, leaving Sea King to move on to the Merlin. The squadron will reform in September 2014, while the RAF Merlin squadron 78 will disband as the helicopters are handed over.
845 NAS continues to serve the Marines, with a mere 11 Sea King HC4 left in service. The squadron will reform with Merlin in August 2015, and sometime in the same year the second and last RAF Merlin squadron (28 Sqn) will disband.
It does not seem to be planned to reform 848 NAS: training will probably be delivered from within the two frontline squadrons. The total number of crews in the force will drop from 43 to 37, with all of them expected to be trained come 2016.

For the disbanding RAF Squadrons, there's a little ray of hope, as one of them might stand up again with Chinook as the new HC6 arrive, but this is not confirmed at the moment.

25 Merlin helicopters will undergo upgrade and navalisation (Phase 2) including the seven interim helicopters. The full program of changes includes electric folding tail, folding rotor head, lash down points, fast rope kit, a cockpit upgrade like that of the naval HM2 helicopters, an integrated digital map system, improved CHF-specific communication systems and uplifted integrated defensive aids suite, including Generation 3 Common Missile Warning System, which actually ads the capability to locate the source of small arms and RPG fire as well.
The first fully reworked helicopter, to be known as HC4 / 4A, will be delivered in late 2017, and the deliveries won't be completed before march 2022.

The ballistic anti-ship missile panic

The reports about China's development of a ballistic anti-ship missile have given new (questionable) arguments for air force fans to attack the aircraft carriers. Too vulnerable, they say, forgetting that ballistic missiles have been a threat for land airfields for many years. At one point, Vertical Take-Off and Landing was the answer to what was expected to be "the end of all airfields", which would be devastated by barrages of missiles and bombs. 
Days ago I wrote a quick comment piece that proved, sadly, a prophecy: while people obsessed about "too vulnerable" aircraft carriers, an attack on Camp Bastion took place, and 6 US Harriers were destroyed on the ground. 
Although it does not appear that this time indirect fire was the main threat, the attack on Bastion proves me right on both the need for improved Base-ISTAR and also the need for an effective C-RAM capability. 

Today I want to return on the subject of the ballistic carrier killer and look at the matter in greater detail to make a few considerations. 

The DF-21D

The new bogey man, I call it, because it is causing all sort of bold assertions and an unjustified amount of panic. The Dong Feng (Eastern Wind, in Chinese) DF-21D (CSS-5 Mod. 4 in NATO nomenclature) is, reportedly, a ship-killing variant of a well known two-stage, solid-propellant, single-warhead medium-range ballistic missile (MRBM) land-based medium range ballistic missile in service in China for several years in nuclear (DF-21A) and conventionally armed variants (DF-21C). The DF-21 itself is a derivation, engineered in the 90s', of the Ju-Lang JL-1 missile originally developed to be launched by the submarines of the Xia class.
The DF-21A is road-mobile, mounted on a trailer towed by a large truck, while the DF-21C is mounted on a WS-2400 Tractor, Erector, Launcher (TEL) 10x10 high-mobility vehicle, which is also used by the DF-21D, to enhance survivability by allowing the system to move offroad, making it harder to locate.
The DF-21C has a payload of 2000 kg, and the DF-21D has probably the same space and weight envelopes. Differently from the C variant, however, the D needs a propulsion system and a complex guidance system fitted in that same space and weight. 

DF-21C missiles on parade. The DF-21D is supposed to look very much like its conventional brother, and share the same TEL vehicle.

Much of what we know about the DF-21D is a mix of speculation, Taiwanese-intelligence and US Intelligence analysis. 
We believed the range of the DF-21D is 2000 km but 3000 have also been suggested, and we assume that it is armed with a single, large maneuverable warhead (MARV) capable to pierce the armored decks of a Nimitz aircraft carrier, even if there is who talks of submunitions meant to destroy sensors and airplanes parked on the deck. 

The warhead is possibly equipped with a hybrid propulsion system, with liquid or solid fuel, in order to be able to maneuver and avoid interception in its exo-atmospheric flight phase. 
Unofficial Chinese sources say that the warhead is fitted with a Synthetic Aperture Radar in order to look down over the target area and locate the ships it is supposed to hit, and for terminal guidance would be provided by a multi-mode seeker combining millimeter-wave radar, electro-optic seeker and possibly passive radar homing. 

According to Taiwanese intelligence reports, the DF-21D should have entered service at the end of the 11th 5-years Plan of China, so around 2010, with a first production block of 15 to 20 missiles. Production is estimated at 10 to 15 units per year, allowing a force, by 2020, that in theory could number 150 launchers. 
For what we know, so far the DF-21D has never been tested against targets at sea, but only against land objectives.

In the words of China itself, the DF-21D is a long term capability that was first announced in 2003 and that plans to deliver: 

- By 2010, a ballistic anti-ship missile capability with a range of 1800 to 2000 Km. 
- Improve range and targeting by 2015
- Extend engagement capability at intercontinental level by 2020 (14.000 km or more) 

This is part of a larger plan of strengthening for the Strategic Missile forces that includes development of hypersonic missiles with global attack capability by 2025. 

A graphic demonstration of the Ballistic Missile capabilities available to China. In red, the indicative range of the DF-21 family.

In the Chinese forces, ballistic missiles are assigned to the 2nd Artillery Corps, which controls the nuclear and conventional missile resources as well as organic Electronic Warfare elements, force protection and support. 
The assumption is that China has so far been giving the DF-21 to two Missile Brigades based in front of Taiwan, each expected to be organized on 6 battalions with 17 launchers each in 2 batteries. This organization is that of the land attack DF-15 missile brigades, that, we assume, will be maintained. 
Within these two brigades, the anti-ship variant of the DF-21 missile is supposed to have been trialed and brought to IOC in 2010. 
Up to 40 anti-ship systems might be in service as we speak. 

And by this time, the number of "assumptions" is already very high. 

The doctrine

The DF-21D employment is part of an operational concept adopted by the Chinese forces to confront an enemy (the US Navy) that they cannot face directly with hopes of victory. 
The use of long-range bombers with anti-ship missiles is nothing new, as it is the approach the old URSS used before China. 
And ballistic anti-ship missiles were probably imagined by the Russians, as well. The idea is that the ballistic missile gives the US navy a difficult enemy to deal with, without China needing to risk any asset near the carrier battlegroups of the Americans. 

Obviously, the long range anti-ship ballistic missile is meant to neutralize aircraft carriers sailing towards China, but it is also meant to cut communications line across the Pacific and isolate hostile powers in the area (Taiwan first of all, obviously, but Japan a close second). 
The ballistic anti-ship missile is meant to keep the US away from the area, in a perfect example of Anti-Access strategy. 
To do so, the conventional DF-21 missiles meant for land attack could be used first, to force the US Navy (incapable to determine the kind of warhead fitted to the missile) to employ its SM-3 anti-ballistic missiles before the actual anti-ship Dong Feng is launched. 
The old tactic of saturation, nothing more, nothing less. 

The US are not helped in countering this tactic by the fact that the SM3 intercepts enemy missiles in their exo-atmospheric phase, so that during a saturation attack done with normal ballistic missiles there would be no real possibility to wait and track the trajectories of the warheads re-entering the atmosphere to hit only those on a dangerous trajectory. 
The US Navy would have to run the risk and hold fire, or potentially waste a huge number of precious interceptors against missiles with nearly zero effective chances of hitting the ships at sea. After that, the actual anti-ship guided warheads would follow, and find the defences of the carrier battlegroup severely short of ammunition. 
To make things worse, currently there is pretty much no way to reload vertical launch cells at sea with new missile canisters, making saturation a real issue, even for ships such as the Burkes and Ticonderoga, which carry dozen of interceptors. 


The doubts

There are many reasons to doubt of the effectiveness of the ballistic anti-ship missile. In our estimates, we are likely giving the new system capabilities it actually does not have. 
The reports about hybrid propulsion, SAR radar and multi-mode seeker bring forth several questions, from the size of the warhead to the feasibility of putting any kind of radar and electro-optic sensor inside such an atmospheric re-entry vehicle. 
The space for the actual warhead is likely to be tiny, if there really is a propulsion system and multiple targeting sensors fitted to the re-entry vehicle. 

Even assuming the tremendous speed of the re-entry into Atmosphere gives the warhead sufficient kinetic energy to be lethal on impact, we come straight to the next issue: developing a seeker window that allows the radar and electro-optic sensors to look out towards the target while resisting to the heat and stress of re-entry into atmosphere. 
The temperatures involved, the speed, the violence of the impact with the atmosphere, are tremendous. A tiny vulnerability in the heat shield means catastrophe, as the shuttle Columbia demonstrated not so long ago with tragic consequences for its crew. 

The actual feasibility of a maneuvering warhead that, during the re-entry phase, can significantly alter its course to detect, track and pursue moving ships that will have changed their position by a good bit since the DF-21D has been launched is also questionable. 
Hitting a ship at sea is not like delivering a large warhead on a static land target with an acceptable CEP. Delivering a nuke or a conventional warhead over a static target of which we know the position is one thing. Hitting a moving ship in the middle of the sea is a whole different story. 
There is too much stuff that must be crammed into the re-entry vehicle. Technology might be moving fast, but it is hard to believe that the Chinese have solved all the issues involved. 

Crucially, the biggest vulnerability of the DF-21D is in the "Find" phase. Even assuming the missile can do what it promises on the tin, the Chinese first need to detect and track the position of the ships to be hit. And this is a task far more complex than most people realize. 
The crucial capability here is that provided by satellites. The Chinese are in fact putting satellites into orbit to provide coverage to the South China Sea, with a number already deployed and 8 more planned. The satellites are of the HJ-1 type, fitted with SAR radar and/or electro-optic sensors, and of the Yaogan type, fitted for ELINT tasks. 

Realistic...?

 
It'll be around satellites that the opening phases of any conflict between the two superpowers will revolve. The "player" that shoots down the most enemy satellites while preserving more of its own, gains a fundamental upper hand. 
Blind the satellites, destroying them or using electronic warfare or just hiding from them (you can actually hide from most satellites, guiding your ships into a different area of sea at the right time, and it is a simple geometrical issue, with times and routes easily calculated upon observation of the orbits of the enemy satellites) and you have seriously reduced the chances of the DF-21D to achieve anything. 

Iran's own missile 

Iran also claims to have developed a ballistic anti-ship missile, but its claim is even less substantial and raises even more doubts than China's own. 
Iran showed images on its state television of a barge in the water being hit and sunk by what was presented as the warhead of a ballistic missile, but hitting a motionless barge for the state television's camera is hardly demonstration of any realistic capability.

The countermeasures 

Since the end of the Cold War, the US Navy carrier wing has massively reduced its long range air defence effort, focusing more on land attack. It cut back on dedicate CAP patrols, and removed the "air defence" fighter from the Wing with the F14, along with the long range anti-air missile, the Phoenix. 
One countermeasure to the Chinese threat will be reversing these decisions, strengthening the carrier wing against air threats. In this sense, the interest for increasing the number of missiles carried by the F35 and the interest in the Meteor long-range missile are both indicative. 
Improved air defence will be indispensable to keep bombers, missiles and, crucially, reconnaissance airplanes and UAVs away from the battlegroup. 

Improved anti-ballistic capability, on land and at sea, is already a necessity, with the proliferation of ballistic threats, from the SCUD to the Iskander, up to the Dong Feng. It is very much likely that the UK itself will have to take note of the ballistic threat at some point (currently, it has nearly zero capability of its own to counter ballistic missiles) and the MOD has indeed studies open, and a partnership with BAE to keep the Type 45 and its Sampson radar up to date and readily available to take on a ABM role. The Type 45 also has space for 16 new missile cells, while Raytheon has developed a data link that would quickly enable the destroyer to employ the SM3 missile in ABM role.

The US is planning to expand progressively the capability of the SM3 missile, and plans to have more ships ABM capable, and more interceptor missiles at the ready. 
There are also studies to fit AMRAAMs with Infra-Red seekers, adapting them as ballistic missile killers, and this could be a cost-effective measure capable to massively increase the resilience of deployed forces against the ballistic threat, even if this project is intended to kill a ballistic missile in its boost phase, thus requiring the launching airplanes to enter enemy airspace. It would arguably be better to have more possibilities of hitting the enemy missiles in the re-entry phase, to counter the Dong Feng. 
The US Navy is also due to enhance air defence for its ships with the SM6, a Standard missile fitted with the radar seeker of the AMRAAM to finally give the Aegis system a fire-and-forget weapon, in place of the current semi-active missiles. This will greatly help in reducing the risk of saturation in front of massive air attacks. The UK in this area leads the way thanks to the formidable performances of the Aster/Sampson combination. 

The age of the UAV can help, too. The US Navy is investing to bring, by 2018 or 2020, the first UCAV into the carrier air wings, as a platform capable to collect intelligence and strike enemy targets at greater distance from the enemy.  This too can be an effective defence: the further away you are from the enemy shore, the harder you are to find and target.


Conclusions 

It is way too early to be frightened by a weapon system of dubious effectiveness, known mostly through stories, suggestions and guesses. There are many good reasons why we should doubt of the effective capabilities of the DF-21D, and there are, in general, good countermeasures already on the way. 
While it would be stupid to ignore the Dong Feng appearance, it would be even worse to fall into panic and start with unsustainable programs for weapons adequate to counter this specific mooted threat. This would only make China happy. It is a trick that NATO itself used against URSS in the Cold War. To fall for the same trick would be rather embarrassing. 

Even more unjustifiable to my eyes is the position of those who say that the aircraft carrier is now "too vulnerable" and destined to lose importance and quickly become obsolete. Its effective vulnerability is questionable, and arguably inferior, in many ways, to the vulnerability of land airbases, no matter how well defended. 
Ballistic missiles have been and are a threat for airfields from many years. It is possible that, in the future, they will be a threat to aircraft carriers as well. But this should not lead to bold and dumb claims.

Ultimately, the "obsolescence" of the aircraft carrier is denied by the simple fact that airplanes, manned or not, still need bases in order to operate. And airplanes are, today more than ever before, fundamental in any kind of operation. 
In my opinion, it is more "likely" that we will see a submarine aircraft carrier one day, more than is likely that we will see the obsolescence of floating bases for aircrafts. 
Just as we depend on runways on land, we depend on runways on the sea. Both kinds of runways are vulnerable in their own ways. 
But until the airplane becomes obsolete, or somehow ceases to need a base from which to operate, there is no alternative to the aircraft carrier just as there is no alternative to the use of airports. 

Has anyone tried to think of the vulnerability of any kind of fleet at sea without the air cover and air support provided by a carrier air wing...?  
Also, has anyone tried to think of the vulnerability of air bases in Japan, South Korea and Taiwan, when on the opposing coast, in China, literally thousands of ballistic missiles are based, ready to be launched for a massive opening strike...? 
Has anyone noticed the events in Camp Bastion...? 

Try and think about it. You're probably going to change opinion about the "vulnerability" of the aircraft carrier.