US Navy Surface-To-Air Missiles

v1.0.0 / 01 jul 20 / greg goebel

* Late in World War 2, the US military became interested in using missiles for air defense. The US Navy pursued two lines of investigation, one focused on the ill-fated "Lark" naval surface-to-air missile (NSAM), and a more successful effort codenamed Project BUMBLEBEE. BUMBLEBEE led to three SAMs, including the "Talos", "Terrier", and "Tartar" -- with Terrier and Tartar leading to the modern "Standard" naval SAM. This document provides a history and description of US Navy SAMs.

Standard Missile launch

[1] LARK

[1] LARK

* Late in World War II, the US Navy ran into Japanese suicide aircraft attacks, the "kamikazes", which proved devastatingly effective against US Navy ships. The kamikazes led to interest in developing a medium-range air-defense system, with longer range than shipboard anti-aircraft guns, but leaving long-range defense to fighter sweeps.

The air-defense effort focused on guided missiles, being split between two projects. The first project, designated "Lark", was a fast-track project, with the Navy Bureau of Aeronautics issuing a preliminary requirement to industry in early 1945. A contract for a hundred Larks was issued to Fairchild in March 1945; because of slow progress by Fairchild, a second contract for a hundred missiles was issued to Convair in June.

The Fairchild Larks were initially designated "KAQ-1", later "XSAM-2" and then "XSAM-N-2"; the Convair Larks were initially designed "KAY-1", later "XSAM-4" and then "XSAM-N-4". Both the Fairchild and Convair missiles looked alike, being cylinders with tapered noses, plus cruciform wings and tailfins. Length was 4.24 meters (13 feet 11 inches), while wingspan was 1.88 meters (6 feet 2 inches), and launch mass was about 550 kilograms (1,220 pounds) -- with a 45-kilogram (100-pound) warhead, detonated by proximity fuze.

Lark SAM

They were powered by a Reaction Motors LR2-RM-2 liquid-fuel rocket motor, with two thrust chamber -- one big for boost power, the other small for cruise power -- and burning "red fuming nitric acid" as fuel, which consisted of mostly nitric acid, plus some nitrogen tetroxide and water. It was as nasty as it sounds. Later items used the more powerful LR2-RM-6 engine, with the designations changed to "KAQ-2 / XSAM-2a / XSAM-N-2a" and "KAY-2" / XSAM-4a / XSAM-N-4a". The Lark was launched by twin rocket-assisted take-off (RATO)" boosters in a frame, which added 1.4 meters (4 feet 7 inches) to the length, and 370 kilograms (810 pounds) to the weight. Maximum range was 55 kilometers (34 miles / 30 NMI).

The two different versions of Lark used different guidance methods:

Some Larks were used for trials in other programs, as discussed below. The Lark program was canceled in 1950; it was subsonic, and better options were available by that time.



* The other branch of effort towards developing NSAMs, known as the "BUMBLEBEE Project", proved much more successful. Initial work was performed by the Applied Physics Laboratory (APL), a government-oriented research organization, associated with Johns Hopkins University in Maryland.

At the outset, the Navy really wanted a long-range supersonic SAM that could intercept adversary attack aircraft before they got in range to release guided antiship weapons. The Navy specified a weapon with a horizontal range of 18.5 kilometers (11.5 miles / 10 NMI) and a ceiling limit of 9,150 meters (30,000 feet), with a circular error of 0.2% -- that is, within a 2-meter circle at 1,000 meters. The circular error dictated a large warhead.

At the time, ramjet propulsion was seen as the best way to meet the speed and range requirements, with flight tests from early 1945 from what would become known as "Burner Test Vehicles (BTV)" -- ramjet vehicles, early on launched with clusters of 12.7-centimeter (6-inch) High Velocity Air Rockets (HVAR). Incidentally, there were of course a number of different versions of the BTV, and there's a tangle of names and designations; they're rendered down here to "BTV" here for simplicity. Initial flight were just aerodynamic tests, with dummy ramjets, but a functional ramjet with a diameter of 25 centimeters (10 inches) was finally flown in October 1945. By 1947, the BTVs had moved up to tests of a 45-centimeter (18-inch) ramjet.

In the meantime, there was work on guidance systems, starting with the "Control Test Vehicles (CTV)" -- which were Larks -- to test out beam-riding. They led to a series of beam-riding "Supersonic Test Vehicles (STV)", leading up to the "STV-3", which was a solid-fuel rocket, launched by a solid-fuel booster. At this point, the Bumblebee program was rethought, with the STV-3 looking like a pretty good short-range NSAM. All that really needed to be done was replace its telemetry module with a warhead and a fuze. The result would be the "Terrier" NSAM, discussed below.

Terrier could be fielded quickly -- which led to expanding the goals for the ramjet-powered missile, extending its range to 90 kilometers (55 miles / 50 NMI) or better, and adding a terminal homing seeker, along with beam-riding guidance. In early 1948, the ramjet-powered missile was given the name of "Talos" -- an ancient guardian demigod of the island of Crete. Talos, so legend went, was made of brass and could fly at great speed, becoming so red hot that he could incinerate enemies simply by grabbing on to them.


In any case, in 1949 the Talos program went on to the "Experimental Prototype Missile (XPM)" series, which had a 71-centimeter (28-inch) ramjet and were much more like operational weapons, with later members of the series featuring guidance systems. The XPMs led in turn in 1951 to flight prototypes for the production Talos missile, the prototype series being designated "XSAM-N-6" -- and then, in 1954, to the pilot-production "SAM-N-6b". Manufacture was performed by the Bendix corporation, with the McDonnell Corporation building the missile airframe as a subcontractor.



* The Talos NSAM, as it emerged, was essentially a "flying stovepipe", a simple tube with a ramjet, with fuel, guidance, and warhead crammed in. It had four pivoting trapezoidal wings for guidance in midbody, and four rectangular. It was launched by a Mark 11 solid-fuel booster, with four fixed rectangular fins; the missile just flew in the direction of launch until the booster was discarded, and then followed the guidance radar beam.

The warhead was in the ramjet centerbody, with electronics ringing the "stovepipe" behind that, and fuel ringing it behind that in turn. fixed fins at the tail. There was a receiver at the tail to track the radar guidance beam, and four antennas at the front -- along with a pitot tube -- for SARH homing. The warhead was detonated by a proximity fuze. SARH permitted the missile to be used as an antiship weapon, as a secondary capability. Images of Talos impacts on target hulks show they could do severe damage.

The initial production SAM-N-6b had a conventional warhead; it was complemented by the "SAM-N-6bw", which had a W30 nuclear warhead, with a yield of a few kilotons. The SAM-N-6bw didn't have a SARH terminal seeker, since it wasn't needed with a nuclear warhead. In 1956, production moved on to the "SAM-N-6b1" and "SAM-N-6bw1" -- conventional and nuclear variants respectively -- with range doubled to 180 kilometers (110 miles / 100 NMI).

continuous-rod warhead

The SAM-N-6b1 also replaced the original fragmentation warhead with a "continuous-rod" warhead, which consisted of a set of steel rods wrapped around an explosive charge, with the rods connected together at the ends so they would expand into a ring that would slice through a target aircraft. Talos was declared operational in 1958. By 1960, production had consolidated on a "Unified Talos" variant, the "SAM-N-6c", that could be fitted with either a conventional or nuclear warhead. It also had a higher ceiling, and an improved SARH seeker. The new seeker was based on continuous-wave radar illumination; the seeker didn't need to gauge distance, it just needed a good signal to home in on.

Talos SAM launch

In 1962, the Pentagon adopted a multi-service common designation scheme, and so the Talos series got the designation of "RIM-8", where "RIM" stood for "Radar Intercept Missile":

   old         new      notes

   SAM-N-6b    RIM-8A   50 NMI range, conventional warhead only
   SAM-N-6bw   RIM-8B   50 NMI range, nuclear warhead only
   SAM-N-6b1   RIM-8C   100 NMI range, conventional (rod) warhead only
   SAM-N-6b1w  RIM-8D   100 NMI range, nuclear warhead only
   SAM-N-6c    RIM-8E   Unified Talos, conventional or nuclear warhead

The size of the Talos and the elaboration of its support systems meant it was only carried by seven US Navy cruisers:

Talos was never exported. A Talos launcher had twin arms that could pivot up and down, with the missiles slung under the arms, and the arms on a rotating post. There were two radars -- the AN/SPG-49 target illumination and tracking radar, and the AN/SPW-2 missile guidance radar, to provide the radar beam for the missile to ride. The beam-rider radar didn't necessarily point directly at the target, the radar instead tracing out the most efficient trajectory for the missile, not a straight-line attack.

   _____________________   _________________   _______________________
   spec                    metric              english
   _____________________   _________________   _______________________

   missile wingspan        2.9 meters          9 feet 6 inches
   missile length          6.4 meters          21 feet
   missile diameter        71 centimeters      28 inches
   missile weight          1,540 kilograms     3,400 pounds
   warhead weight          136 kilograms       300 pounds

   booster length          5.2 meters          17 feet
   booster diameter        76 centimeters      30 inches
   booster weight          2,000 kilograms     4,400 pounds

   total length            11.6 meters         38 feet
   total weight            3,540 kilograms     7,800 pounds

   speed                   Mach 2.5
   ceiling                 24,400 meters       80,100 feet
   range                   185 kilometers      115 MI / 100 NMI
   _____________________   _________________   _______________________

The new SARH seeker on the RIM-8E was retrofitted to some RIM-8Cs, these missiles then being redesignated "RIM-8F". There were also "RIM-8G" and "RIM-8J" variants, with consecutively refined seekers -- and maximum range extended to 240 kilometers (150 miles / 130 NMI), through use of a high-energy "dimer" fuel.

nuclear Talos SAMs

Talos saw action with the cruisers CHICAGO and LONG BEACH in the Vietnam War. LONG BEACH drew first blood on 23 May 1968, hitting a North Vietnamese MiG fighter at a range of 105 kilometers (65 miles), with a second MiG destroyed by flying into the debris. LONG BEACH destroyed a third MiG in September 1968. CHICAGO shot down a MiG on 9 May 1972, late in the war. These were the only aircraft shot down by Talos in combat.

In addition, there was the "RIM-8H Talos Anti-Radiation Missile (ARM)", which was a surface-to-surface weapon that would home in on a radar station or other "emitter". Presumably, the warhead was changed to a blast-fragmentation configuration. It was first flight-tested in 1965, and saw action in the Vietnam War with the CHICAGO, OKLAHOMA CITY, and LONG BEACH. The CHICAGO performed the first attack in early 1972 -- this being the first time a US Navy ship fired a long-range surface-to-surface missile.

Talos variants

Talos was withdrawn from front-line service in 1979, with several hundred refurbished as "MQM-8G Vandal" targets, featuring a sea-skimming guidance system, and intended to emulate antiship missiles for naval training. The series included a stretched "Extended Range" variant, with GPS navigation fitted to some of the targets. The last Vandals were expended in 2008. A number of Talos rounds survive on static display.

* As a footnote to the Talos story, in the late 1950s, the US Navy began to investigate a replacement for the Talos and the other naval SAMs developed in that decade. The biggest problem with the existing NSAMs was guidance, which demanded that each missile have its own dedicated targeting system -- which would leave a warship vulnerable if attacked by a mass of enemy aircraft.

The result was the "SAM-N-8 Typhon LR", later "RIM-50A", which was clearly derived from Talos, and indeed was known as the "Super Talos" early on. The name "Typhon" was from the Greek demigod of volcanoes. The Typhon featured a ramjet-powered missile stage and a solid-rocket booster stage. Its primary visible difference from the Talos missile was that Typhon had, instead of wings and tailfins, long narrow delta wings, with control surfaces at the tips. Like the Talos, the warhead was in the ramjet centerbody, and could be either conventional or nuclear.


The guidance system was based on midcourse navigation by an inertial navigation system (INS) with terminal SARH guidance, meaning the missile didn't have to be under control of shipboard radar systems at all times. It was to be under the direction of the AN/SPG-59 phased-array radar system, which would be able to track and engage multiple targets at the same time. The missile would have a secondary surface-to-surface capability.

   _____________________   _________________   _______________________
   spec                    metric              english
   _____________________   _________________   _______________________

   missile wingspan        1.02 meters         3 feet 4 inches
   missile length          4.72 meters         15 feet 6 inches
   missile diameter        41 centimeters      16 inches
   missile weight          770 kilograms       1,700 pounds
   warhead weight          68 kilograms        150 pounds

   booster wingspan        1.57 meters         5 feet 2 inches 
   total length            8.41 meters         27 feet 7 inches
   total weight            1,640 kilograms     3,620 pounds

   speed                   Mach 4.0
   ceiling                 29,000 meters       95,000 feet
   range                   370 kilometers      230 MI / 200 NMI
   _____________________   _________________   _______________________

Work on Typhon was conducted by the Bendix Corporation, with initial test launches in 1961 and sea trials in 1962. However, the cost of the program escalated painfully, while technical problems kept popping up -- the program was simply too ambitious for the technology available at the time. Typhon was finally canceled in 1963, with the Navy reconsidering requirements. There was also thought of "SAM-N-9 Typhon MR", later "RIM-55MR", originally named "Super Terrier" -- which, as the name suggests, was to be a Terrier follow-on. It never flew.



* The first test flight of an all-up Terrier was in 1953. It entered service in 1956, two years before Talos, with the first vessel to carry the weapon being the USS CANBERRA. It was produced by Convair -- which was purchased by General Dynamics in that year, with the Convair name being dropped early in the next decade. The initial variant was the "SAM-N-7 / BW-0" -- the "BW" meaning "beam-riding, wing-controlled" -- which was quickly replaced by the "BW-1", which was much the same, except for redesigned electronics and generally better reliability.

The Terrier, as it emerged, was configurationally broadly similar to the Talos, with a missile featuring cruciform pivoting wings in mid-length, plus fixed cruciform tailfins, powered by a solid-fuel booster with fixed cruciform fins. The missile differed by being powered by solid-fuel rocket motor, not a ramjet -- and it was strictly a beam rider, with no SARH capability. It could only engage subsonic targets; it had a top speed of only Mach 1.8, and a range of only 19 kilometers (12 miles).

early Terrier

Early on in the Terrier development program, a push began to develop an improved "Terrier II", with test flights of "STV-4" and then "STV-5" vehicles. The STV-5 led to the "BT-3", which was introduced in 1958, the "BT" meaning "beam-riding, tail controlled". It was still purely a beam-rider, but replaced the wings with fixed strakes, with control provided by the tailfins, which substantially improved the missile's agility. It had Mach 3 performance and could engage supersonic targets.

It was followed by the "BT-3A", which doubled the range to about 37 kilometers (23 miles / 20 NMI), along with the "BT-3A(N)", which was fitted with a W45 nuclear warhead, with a kiloton yield. It was the only nuclear Terrier. The "HT-3" variant introduced SARH terminal homing -- the "HT" meant "homing Terrier" -- primarily to make the Terrier more effective against low-flying targets. SARH also allowed it to be used as an antiship weapon. The Terrier II had envisioned SARH terminal guidance all along, but it proved difficult, and so had to be put off.

In 1962, Terrier designations were revised as follows:

   old               new      notes
   SAM-N-7 BW-0      RIM-2A   initial variant, wings control, beam riding
   SAM-N-7 BW-1      RIM-2B   cleaned-up BW-0
   SAM-N-7 BT-1      RIM-2C   tail control, supersonic targets
   SAM-N-7 BT-3A     RIM-2D   doubled range
   SAM-N-7 BT-3A(N)  RIM-2D   nuclear warhead
   SAM-N-7 HT-3      RIM-2E   SARH homing

After 1962, one more version was introduced, the "RIM-2F", which featured:

The RIM-2F was also known as the "HTR-3", for "homing Terrier retrofit". The last Terriers were produced in 1966, after manufacture of about 8,000 missiles.

   _____________________   _________________   _______________________
   spec                    metric              english
   _____________________   _________________   _______________________

   missile length          4.6 meters          15 feet
   missile wingspan        61 centimeters      24 inches 
   missile tailfin span    1.07 centimeters    42.3 inches 
   missile diameter        34 centimeters      13.5 inches
   missile weight          535 kilograms       1,180 pounds
   warhead weight          100 kilograms       218 pounds

   booster length          3.4 meters          11 feet 4 inches
   booster weight          825 kilograms       1,820 pounds

   total length            8.0 meters          26 feet 4 inches
   total weight            1,360 kilograms     3,000 pounds

   speed                   Mach 3.0
   ceiling                 24,000 meters       80,000 feet
   range                   32 kilometers       19.8 MI / 17.3 NMI
   _____________________   _________________   _______________________

The Terrier ended up being a standard US Navy weapon, being carried on missile cruisers and guided-missile destroyers. It was fired from a Mark 10 twin-arm launcher, similar to that of Talos. Ships typically had a 40-round rear-loading magazine, but some vessels had magazines with 60 or 80 rounds -- while the heavy guided-missile cruisers USS BOSTON and USS CANBERRA featured a bottom-loading magazine with 72 rounds.

later Terrier

Terrier was also operated by the navies of Italy and the Netherlands. It doesn't seem the Terrier saw much action. On 19 April 1972, a Terrier launched by the guided missile cruiser USS STERETT , 1972, a Terrier missile fired by USS STERETT shot down a North Vietnamese MiG-17F. It's hard to find records of any other kills.

* The US Marines actually used the Terrier as a ground-based SAM for two years in the 1950s, missiles being fired from a transportable version of the sea launcher, which was complemented by a support vehicle that could carry reloads. It was the first SAM used by the Marines. It was replaced by the Raytheon Hawk SAM in Marine service.

The Terrier booster rocket was leveraged by the Army into a booster rocket for the Army Nike-Ajax SAM. Retired boosters from Talos, Terrier, and Nike-Ajax were used with sounding rockets -- with such boosters occasionally fitted in tandem combinations or pairs.



* Terrier was still too big for smaller ships like frigates, and so the solid-rocket rocket booster was dropped from the RIM-2E, with the result being the short-range "RIM-24A Tartar" NSAM, introduced in 1963. It featured a continuous-rod warhead, and a Mark I dual-thrust (boost-sustain) solid-rocket motor -- Terrier never used a dual-thrust motor, since Terriers had the booster stage. Range of the RIM-24A was 16 kilometers (10 miles / 9 NMI), with ceiling up to about 15,000 meters (50,000 feet).

Tartar SAM launch

The RIM-24A was followed by the "RIM-24B", which was about 12 centimeters (5 inches) longer and featured with an improved seeker, a more potent warhead, plus a new Mark 27 dual-thrust motor that extended range to 30 kilometers (18 miles / 16 NMI), and raised ceiling to 20,000 meters (65,000 feet). Many Tartars were modified under the "Tartar Reliability Improvement Program (TRIP)" AKA "Improved Tartar Retrofit (ITR)", with solid-state electronics, better counter-countermeasures, and the ability to engage more than one target. They also had slightly improved range and ceiling, because they were lighter. Missiles given the TRIP were redesignated "RIM-24C".

   _____________________   _________________   _______________________
   spec                    metric              english
   _____________________   _________________   _______________________

   wingspan                61 centimeters      24 inches 
   tailfin span            107 centimeters     42.3 inches 
   length                  4.6 meters          15 feet
   diameter                34 centimeters      13.5 inches
   weight                  590 kilograms       1,310 pounds
   warhead weight          60 kilograms        130 pounds

   speed                   Mach 1.8
   ceiling                 20,000 meters       65,000 feet
   range                   32 kilometers       19.8 MI / 17.3 NMI
   _____________________   _________________   _______________________

All Tartar variants had an antiship capability, using SARH for terminal attack, with a maximum range -- clearly limited by radar line-of-sight -- of about 18 kilometers (11 miles). The Tartar was initially launched from the twin-arm Mark 11 launcher, later from the Mark 13 and then Mark 22 single-arm launcher. Foreign navies that adopted the Tartar included those of Australia, France, Germany, Italy, Japan, and the Netherlands. The Germans investigated a dedicated antiship version of the Tartar, with a Bullpup air-to-surface missile warhead, but obtained the French MM38 Exocet antiship missile instead.

Terrier family

* France, as noted, was a Tartar user, and decided to use as a basis for for a Terrier-like SAM, the "MASURCA" -- an acronym for "Marine Surface Contre-Avions / Naval Surface [vessel] Anti-Aircraft)". The "Mark 1 Mod 1" was a prototype weapon; the "Mark 2 Mod 2" was the first operational version, being introduced in 1968.


The missile itself looked like a Tartar, but had a French-made solid-rocket booster with different proportions from that of the Terrier. The MASURCA was fired from a twin-rail launcher, with 17 missiles in a horizontal-loading magazine. Sources are very confusing on guidance; it appears the Mod 2 was command-guided, with no terminal homing, and a proxity fuze for detonation.

A "Mark 2 Mod 3" version replaced the Mod 2 from 1975, this version adding SARH for terminal attack. The MASURCA saw service on the frigates SUFFREN and DUQUENSE, as well as the guided-missile cruiser COLBERT. The MASURCA was finally withdrawn in 2008.



* Having found the Tartar and Terrier excellent weapons, in the early 1960s, the Navy decided to evolve them as the "Standard missile (SM)" family, with the Tartar becoming the "RIM-66 SM MR" -- "MR" for "medium range" -- and Terrier becoming the "RIM-67 SM ER" -- "ER" for "extended range".

Test flights of "YRIM-66A" prototypes began in 1965, with the initial "RIM-66A SM-1MR" variant introduced to service in 1967 for existing Tartar warships. It was built in Blocks I to IV; Blocks I & II may have been prototype only, with Block IV being the main production variant. It was called "Digital Tartar", being effectively a Tartar with a comprehensive avionics update, featuring better resistance to countermeasures, and shorter minimum range. It had the same Mark 27 dual-thrust motor, same continuous-rod warhead, and same performance specs.

The RIM-66A did visibly differ from the Tartar by having distinctive forward extensions on the wings, with these extensions being a good recognition feature of the SM family. However, there are confusions in that; although Tartars don't have forward extensions on the wings, later-model Terriers do, though they look more like wedges than airfoils. It is not clear if the wedges served as reinforcements, or had some aerodynamic purpose, or both,

To confuse matters further, images sometimes appear to be mismarked -- in particular, identifying as a Tartar a missile with forward wing extensions, and presumably a Standard. In sum, while there was a clear evolution in form in the Terrier / Tartar / SM family, trying to nail down precise variants from photos is an exercise in futility.

Standard SM-1 MR

Anyway, with a Mark 30 single-thrust motor and a Mark 12 booster attached, the RIM-66A became the "RIM-67A SM-1ER", for existing Terrier warships. It is not clear how block updates to the RIM-66 for traditional Tartar warships applied to the RIM-67A. Production of the SM-1 was originally by General Dynamics, with the line later sold off to Hughes, and finally ending up in the hands of Raytheon. It's complicated.

The "RIM-66B" AKA "SM-1MR Block V" was a much more comprehensive update, with an improved seeker, more agile autopilot, plus a new blast-fragmentation warhead, and a more powerful Mark 56 dual-thrust rocket motor, which extended range and ceiling. It was 25 centimeters (10 inches) longer than the RIM-66A, with length extended from 4.47 meters (14 feet 8 inches) to 4.72 meters (15 feet 6 inches), and weight increased by 42 kilograms (93 pounds). In effect, it was new wine in an old bottle, a new weapon in an old airframe. All RIM-66As were updated to RIM-66B standard.

   _____________________   _________________   _______________________
   spec                    metric              english
   _____________________   _________________   _______________________

   length                  4.72 meters         15 feet 6 inches
   diameter                34 centimeters      13.4 inches
   finspan                 1.07 meters         42.3 inches 
   weight                  620 kilograms       1,370 pounds
   warhead weight          60 kilograms        130 pounds

   speed                   Mach 3.5
   ceiling                 24,400 meters       80,000 feet
   range                   46 kilometers       29 miles / 25 NMI
   _____________________   _________________   _______________________

   RIM-67A SM-1ER:
   _____________________   _________________   _______________________

   booster length          3.81 meters         12 feet 6 inches 
   booster finspan         1.57 meters         62 inches 
   booster diameter        45 centimeters      18 inches
   booster weight          720 kilograms       1,590 pounds

   overall length          7.98 meters         26 feet 2 inches
   overall weight          1,340 kilograms     2,960 pounds

   speed                   Mach 3.5
   ceiling                 24,000 meters       80,000 feet
   range                   65 kilometers       40 miles / 35 NMI

   _____________________   _________________   _______________________

The "RIM-66C" AKA "SM-2MR Block I", introduced in 1978, was the next step beyond that, integrating the Standard missile into the Aegis combat system, which would be fielded on US Navy TICONDEROGA-class guided missile cruisers and ARLEIGH BURKE-class guided-missile destroyers. The Aegis system is built around the AN/SPY-1 radar, which uses four fixed passive phased-array antennas. Aegis is integrated with all shipboard weapon systems; it can track 100 targets at a time, though it's not clear if they can all be engaged at one time.

The RIM-66C a new Mark 115 blast-fragmentation warhead, and an inertial / command guidance system. It picked up where the Typhon program had left off, 15 years earlier, providing a missile that didn't need a dedicated guidance system. The Aegis system could program a flight path for the missile before launch, and update it on the fly. The new flight control scheme was much "smarter" and more efficient, increasing effective range to 74 kilometers (46 miles / 40 NMI).

The RIM-66C also had a "monopulse" radar seeker, with a quadrant radar receiver -- which allowed it to determine target speed and direction with a single radar pulse, instead of multiple pulses, increasing its resistance to deception jamming. There were never any RIM-67 / SM-2ER variants for Aegis warships; the first five Aegis cruisers only had the Mark 26 twin-rail launcher, used for Tartar.

The "RIM-66D" was the same as the RIM-66C, but for Tartar ships. The RIM-66D was also known as the "SM-2MR Block I NTU" -- where "NTU" stood for "New Threat Upgrade", a Reagan-era effort in which old Tartar warships were comprehensively upgraded with new combat systems, including the SM-2-series missiles. The "RIM-67B / SM-2ER NTU" was the equivalent for Terrier NTU warships. Incidentally, sources hint that, along with the ability to use the SM-2 missile, NTU warships could share targeting systems, for example with an NTU cruiser firing the missile, while an AEGIS warship guided it to target.

Again, it is not clear how RIM-66 block updates for Tartar NTU warships applied to the RIM-67B -- though there was a "RIM-67C / SM-2ER NTU Block II", with a new Mark 70 booster stage that almost doubled range, to 185 kilometers (160 miles / 100 NMI), and increased speed to Mach 3.5.

The "RIM-66E" AKA "SM-1MR Block VI" was an improved RIM-66B for Tartar warships, introduced in 1983. It leveraged off technology developed for the SM-2, including the monopulse seeker and Mark 115 warhead. It introduced a Mark 45 Mod 4 proximity fuze AKA "Target Detection Device (TDD)"; this was updated to the Mod 6 in the "Block VIA" and Mod 7 in the "Block VIB". The RIM-66E was the last SM variant for older warships not fitted with the NTU system. There was a "RIM-67D / SM-2ER Block III" with the TDD, and a new Mark 30 Mod 4 sustainer motor for the missile stage.

The "RIM-66G" AKA "SM-2MR Block II", introduced in 1983, was for Aegis warships. It featured a new Thiokol Mark 104 solid-fuel rocket motor that almost doubled range, and an improved fragmentation warhead. It was followed by the "RIM-66H" AKA "SM-2MR Block II", which was much the same, but was intended for the "Mark 41 Vertical Launch System (VLS)".

Standard SM-2 MR

One of the little puzzles of the SM-2 series is that, at some time during the weapon's evolution, the wings / strakes ended up being mid-mounted, instead of extending to the rear. Sources are uninformative on this matter; the wing configuration may have been changed to support VLS, since it is hard to find any images of SM-2 launches from a VLS with the older wing configuration. However, it is possible to find images of SM-2s with the new wing configuration being fired from rail launchers.

The "RIM-66J" AKA "SM-2MR Block II (NTU)" was for Tartar warships, and featured better counter-countermeasures. It was followed by the "RIM-66K-1" AKA "SM-2MR Block III (NTU)" in 1988, which had improved capability against low-altitude targets -- and then the "RIM-66K-2" AKA "SM-2MR Block IIIA (NTU)", introduced in 1991, which had a Mark 125 warhead with a directional blast capability. This was the last of the Tartar-type RIM-66 missiles, with Block II missiles generally updated to Block III standard.

The RIM-66K series was paralleled by "RIM-66L" missile variants for Aegis warships with the Mark 26 rail launcher, including the "RIM-66L-1", with improved capability against low-altitude targets; and the "RIM-66L-2", with the Mark 125 warhead. For Aegis warships with the Mark 41 VLS launcher, there were the "RIM-66M-1" and "RIM-66M-2" variants respectively. The RIM-66L and RIM-66M variants had the same block designations as the RIM-66K variants.

Eventually, Aegis warships would get rid of the Mark 26 launcher, and standardize on VLS. The US Navy no longer operates Talos / Terrier NTU vessels, though it appears some foreign navies still have a few Talos NTU warships. Some sources mention that old RIM-67 missiles have been converted into targets, but it's hard to find confirmation of that.

The "RIM-66M-5", introduced in 1998, was the product of the "Missile Homing Improvement Program (MHIP), adding an infrared homing seeker along with the SARH seeker -- allowing it to defeat anti-radar countermeasures, and also smaller targets. It was the only RIM-66M subvariant that didn't have IMRIM-66K or RIM-66L equivalent. All Block III / IIIA missiles were upgraded to Block IIIB standard.

RIM-156A launch

The lack of an ER version of the SM-2 for Aegis vessels led to the development of the "SM-2ER Block IV", AKA "RIM-156A", which was a Block IIIB missile with a Mark 72 solid-fuel booster stage. The Mark 72 was short, allowing the RIM-156 to fit into a VLS silo; it lacked fins, using vectored thrust for steering.

   _____________________   _________________   _______________________
   spec                    metric              english
   _____________________   _________________   _______________________

   finspan                 1.07 meters         42.3 inches 
   length                  4.72 meters         15 feet 6 inches
   diameter                34 centimeters      13.4 inches
   weight                  705 kilograms       1,555 pounds
   warhead weight          60 kilograms        130 pounds

   speed                   Mach 3.5
   ceiling                 > 24,400 meters     > 80,000 feet
   range                   > 160 kilometers    > 100 miles / 85 NMI
   _____________________   _________________   _______________________

   _____________________   _________________   _______________________
   spec                    metric              english
   _____________________   _________________   _______________________

   booster diameter        53 centimeters      21 inches
   booster length          1.86 meters         6 feet 1 inch
   booster weight          745 kilograms       1,645 pounds

   overall length          6.58 meters         21 feet 6 inches
   overall weight          1,450 kilograms     3,200 pounds

   speed                   Mach 3.5
   ceiling                 > 33,000 meters     > 110,000 feet
   range                   > 360 kilometers    > 225 miles / 35 NMI

   _____________________   _________________   _______________________

* Incidentally, the only known aerial kill of an aircraft by a Standard Missile was on 3 July 1988, in the course of US Navy escorts of tankers in the Persian Gulf during the Iran-Iraq war. Crew of the USS VINCENNES, an early TICONDEROGA-class cruiser with the Mark 26 launcher, spotted an aircraft approaching that they couldn't identify. The captain, Will Rogers, had little time to react, and ordered that the aircraft be fired upon. Two SM-2 missiles were fired, destroying the target.

It turned out to be an Airbus A300 airliner, Flight 665 of Iran Air; all 290 on board were killed. A Navy after-action report chalked up the tragedy to the confusions of war -- though another Navy officer who had been under Rogers' command suggested he was overly aggressive, too quick to open fire. Whatever the case, Rogers became an unfortunate footnote of history. His Navy career may have suffered as well: he never made admiral, and retired in 1991.

Earlier in 1988, on 18 April, the SM-2 played a role in Operation PRAYING MANTIS, a retaliatory attack for the mining of the US Navy frigate SAMUEL B. ROBERTS four days earlier. The Americans attacked two oil platforms being used as operational bases by the Iranians, while sinking an Iranian frigate, gunboat, and three fast attack boats. SM-2s were used in the course of the action.

It wasn't until 2016 that the SM-2 was used again. In October of that year, during the Saudi-driven war in Yemen, the US Navy destroyer USS MASON was repeatedly fired upon by Houthi rebels, who launched antiship missiles at the vessel. The missiles were defeated by countermeasures, SM-2s, and Evolved Sea Sparrow SAMs. On 13 October the USS NITZE, another US Navy destroyer, launched three Tomahawk cruise missiles to neutralize Houthi radar stations that were directing the attacks. It is an indication of the changes in maritime warfare since the end of World War II that shootouts at sea have largely become a thing of the past.

* The SM family featured a number of offshoots. During the Vietnam War, US attack aircraft used the "AGM-45 Shrike" anti-radar missile (ARM), which was an AIM-7 Sparrow air-to-air missile (AAM) with a radar-homing seeker. It lacked range and hitting power, so the early-model RIM-66 was modified for air carriage and fitted with a radar homing seeker, to become the "AGM-78A Standard ARM (STARM)". It was used by both the US Navy and US Air Force -- indeed, it seems the USAF was the primary user.


Refined "AGM-78B" and "AGM-78C" versions were built, with total production being over 3,000 missiles before end of production in 1976. The AGM-78 STARM remained in service into the late 1980s, when it was replaced by the "AGM-88 High-Speed ARM (HARM)", which was more or less a scaled-up Shrike. An "RGM-66D" shipboard ARM was also developed, though it is unclear how much service it saw.

There was work to develop a long-range AAM, the "AIM-97 Seekbat", based on the Standard missile, but it never entered service. The eccentric name was based on the fact that the AIM-97, in part, intended to deal with the high-performance Soviet MiG-35 "Foxbat" interceptor / reconnaissance aircraft. The need was met by the AIM-54 Phoenix missile. During the 1990s, the US Marines also tried to develop a precision-strike surface-to-surface missile, the "RGM-165", based on the Standard,

Iran obtained the SM-1 NSAM in the 1970s, before the fall of the Shah, and eventually built it themselves, as the "Sayyad-2". It uses a guidance system derived from that of the "Sayyad-1" SAM, an Iranian-made version of of the Chinese HQ-2 SAM, which is in turn an improved derivative of the classic Russian S-75 Dvina / NATO SA-2 "Guideline" SAM. It is not clear how the guidance system works; the original S-75 SAM used a target-tracking and a missile-tracking radar, with control updates sent to the missile, much like the MASURCA guidance system. However, the Chinese appear to have enhanced the S-75 to a degree.

Sayyad-2 SAM

The Sayyad-2 is the attack element of the "Talaash" mobile air-defense system. The missile is canister-launched, from wheeled vehicle with four canisters in a 2 x 2 arrangement; presumably, the air-defense system can be mounted on naval vessels as well. There are mentions of further improved "Sayyad-3" and "Sayyad-4" SAMs, but it appears they don't look so much like the Sayyad-2.



* Under the "Navy Area Wide (NAW)" program, the US conducted work on a "RIM-156B / SM-3ER Block IVA" that would have anti-ballistic missile (ABM) capability, but the program went out of control, and was canceled in late 2001. In 2003, the Navy awarded a contract to Raytheon to develop a follow-on to the RIM-156A under the "Extended Range Active Missile (ERAM)" program, this weapon not intended to have ABM capability.

The resulting "RIM-174 / SM-6 Standard ERAM Block I" was fielded from 2013, complementing Block IIIB SM-2s in service. It looks just like the RIM-156A, but features an active radar seeker derived from that used on the AIM-120 AMRAAM air-to-air missile -- also built by Raytheon. It is not fitted with an infrared seeker. The SM-6's ability to self-target gives it an over-the-horizon capability, with a range of up to 370 kilometers (230 miles / 200 NMI). It also supports the "Cooperative Engagement Capability", able to be guided by radars from vessels other than the one that launched the missile -- and ultimately, to be guided by air platforms like the Lockheed F-35 strike fighter. The active radar seeker is being fitted to the SM-2 Block IIIB, resulting in the "Block IIIC", for introduction after 2022.

The RIM-174 "Block IA" subvariant fixed a number of bugs, and also acquired a capability to intercept low-flying cruise missiles. It is being enhanced with GPS navigation to give it a long-range precision strike capability. An "SM-6 Dual-1" mod -- the interpretation of the name is unclear -- has been implemented that gives the missile a low-altitude terminal defense against ballistic missiles.

In the meantime, alongside the NAW program, the Navy was conducting a "Navy Theater Wide (NTW)" program, towards a specifically-designed ABM weapon. The result was the "SM-3", with testing of the developmental "RIM-161A / SM-3 Block I" begun in 2001. The SM-3 also looks much like the SM-156A, but it has a fast-burn / high-acceleration booster stage, and was actually a three-stage weapon -- with a "hit to kill (HTK)" upper stage, the "Lightweight Endo-Atmospheric Projectile (LEAP)". The HTK vehicle was intended for "endo-atmospheric intercept", meaning it could hit targets in near-space. The LEAP stage doesn't have a warhead, it simply smashes into the target directly. The SM-3 uses a Global Positions System satellite receiver and inertial navigation system for midcourse guidance.

SM-3 launch

Aegis warships enhanced to launch the SM-3 had to be brought up to AN/SPY-1E radar configuration -- which was an "active array" radar, as opposed to the passive arrays of earlier variants. Only a few Aegis warships were updated to the AN/SPY-1E at the outset. The SM-3 was fielded in 2006, the initial operational version being the "RIM-161B / SM-3 Block IA", with a one-color infrared seeker. The Block IA was followed by the "RIM-161C / SM-3 Block IB", updating the Block IA with a kill vehicle featuring an improved two-color seeker, avionics, and maneuvering thruster system.

Ongoing testing of the RIM-161 demonstrated growing improvement in intercepting ballistic missiles, though progress was by no means in a neat straight line. In one particularly interesting exercise, on 20 February 2008, an SM-3 fired from the Aegis cruiser LAKE ERIE from off of the Hawaiian Islands actually intercepted a satellite. The satellite was a classified spacecraft, designated "NROL-21", that had failed in orbit after being launched in December 2006.

It was falling to Earth anyway, with the stated rationale for the interception merely to ensure that it was broken up thoroughly so it wouldn't present a hazard when it came down. However, the Chinese had performed a test of an antisatellite system not long before, and it seems plausible the Americans wanted to drop a hint that they had the capability to respond in kind. If so, the hint appears to have been effective, since the Chinese protested loudly.

The Block IB was followed in turn by the developmental "RIM-161D / SM-3 Block II", intended to provide much greater range, with the diameter of the missile stage increased from 34 to 53 centimeters (13.4 inches to 21 inches) -- matching the width of the fast-burn booster. It is not clear if the SM-3 Block II was ever flown; it was refined into the production "Block IIA", with a bigger kill vehicle, featuring a smarter seeker and more powerful divert thrusters.

SM-3 Block IIA

Japan collaborated in this stage of the effort. Raytheon was awarded a contract in 2019 for an initial production batch of Block IIA missiles, with Japan to get its share. There was to be a "Block IIB", but it was canceled in 2013. The Block IIA represents a dramatic evolution of the Standard Missile family, tracing its roots back to the RIM-2 Terrier, conceived in the 1940s, as an outgrowth of the STV test vehicles. The RIM-174 is now also being updated with a 53-centimeter / 21-inch missile stage as the "SM-6 Block IB", to be introduced to service after 2024. Navy documents suggest it may have a hypersonic surface-attack capability.

A land-based variant of the NTW system, named "Aegis Ashore", has been developed, with a ground-based AN/SPY-1 system -- by all appearances, the shipboard system mounted on concrete -- and an SM-3 VLS battery. It was initially fielded in Romania in 2016. Poland will host a second site, though its completion has been repeatedly delayed.

* A summary list of SM variants follows:



* Sources include:

* Illustrations details:

* Revision history:

   v1.0.0 / 01 jul 20