Australia Getting U.S. Containerized Submarine-Tracking Sonar System

Australia is set to become the latest customer for the U.S.-developed Surveillance Towed Array Sensor System–Expeditionary, or SURTASS-E, a passive submarine detection system. The move to acquire SURTASS-E is the latest step in Australia’s ambitious undersea warfare modernization effort, the flagship program of which will see the Royal Australian Navy, or RAN, introduce its first nuclear-powered, conventionally armed submarines, against the backdrop of increasing concerns about the Chinese submarine threat.

The U.S. Defense Security Cooperation Agency (DSCA) yesterday announced that the State Department has approved a possible Foreign Military Sale to Australia of an undisclosed number of SURTASS-E systems, at an estimated total cost of $207 million.

A basic diagram showing the SURTASS system’s components. The SURTASS-E is a further development of the SURTASS, in containerized form, but lacking the low-frequency active (LFA) sonar array. U.S. Navy

So far, it’s unclear what specific ships the systems will be installed in, with the DSCA statement mentioning only that they are intended for “Vessels of Opportunity (VOO).” However, SURTASS-E was always intended to be packaged in standardized shipping containers, or ISO-Vans, which can be readily installed on various suitable ships, as required.

As well as the SURTASS-E mission systems themselves, the declared price tag also includes a shore-processing mission system, a spare SURTASS passive acoustic array, containers, communications parts and support equipment, software, publications, training, U.S. government and contractor engineering support, and other related logistics and program support elements. Lockheed Martin will be the primary contractor for the program.

The original SURTASS system was developed during the Cold War. It comprises ship-towed passive and active sonar arrays and provides “long-range detection [of submarines] and cueing for tactical weapons platforms or other vessels of interest,” according to the U.S. Navy.

The U.S. Navy’s SURTASS was updated in the late 1980s to include a low-frequency active (LFA) sonar capability, which “provides an active adjunct capability for IUSS [Integrated Underwater Surveillance System] passive and tactical sensors to assist in countering the quieter diesel and nuclear threats of the 1990s and beyond,” according to the service. The LFA is especially useful for detecting slow-moving quiet threats in littoral waters.

Originally fielded by the U.S. Navy on its Stalwart class ocean surveillance ships, SURTASS was then switched to multiple different catamaran-style vessels with the introduction of the LFA upgrade. After the end of the Cold War, the SURTASS system became a much lower priority and, today, the SURTASS towed array is found only on the USNS Impeccable and the four ships in the Victorious class, although it has also been exported to Japan, for use on the three Hibiki class ocean surveillance ships. Australia will be only the second foreign customer for SURTASS, further emphasizing the significance of these plans.

The SURTASS-equipped Victorious class ocean surveillance ship USNS AbleU.S. Navy

Compared to SURTASS, the SURTASS-E system, the development of which began in 2017, does not feature an active sonar capability, although it offers greater flexibility thanks to its containerized, modular nature. As mentioned, we don’t yet know what ships the systems will be installed in and whether they will be fitted to existing ships or a new class of vessels. Bearing in mind the kinds of surveillance ships that are outfitted with the original SURTASS, one candidate might be the RAN’s two remaining Paluma class of hydrographic survey motor launches. These share the catamaran hull form also found on the USNS Impeccable and the Victorious and Hibiki classes.

HMAS Shepparton, one of the two remaining Paluma class of hydrographic survey motor launches. Australian Department of Defense

Work on SURTASS-E was carried out under a so-called Rapid Prototyping, Experimentation, and Demonstration, or RPED, effort, which led to a first-ever operational patrol of an appropriately equipped vessel in the Atlantic in 2019.

Since work on the SURTASS-E began, the U.S. Navy has also embarked on developing a new, more rapidly deployable, fixed, persistent, deep-water active anti-submarine surveillance system. This is known as the Affordable Mobile Anti-Submarine Warfare Surveillance System, or AMASS, and you can read more about it here.

For the Royal Australian Navy, or RAN, the SURTASS-E promises to enhance the service’s ability to detect and track submarines, also at extended ranges, including the advanced new submarine designs coming from China.

The PLAN’s Type 039A Yuan class submarine. U.S. Navy

“This proposed sale will support the foreign policy and national security objectives of the United States,” the DSCA declares. “Australia is one of our most important allies in the Western Pacific. The strategic location of this political and economic power contributes significantly to ensuring peace and economic stability in the region. It is vital to the U.S. national interest to assist our ally in developing and maintaining a strong and ready self-defense capability.”

More specifically, the DCSA states that the proposed sale of SURTASS-E “will improve Australia’s capability to meet current and future maritime threats by providing tactical platforms with the detection and cueing of enemy submarines. The ability to provide acoustic wide-area surveillance and generate indications and warnings to Australian commands will significantly improve shared maritime security. Australia will have no difficulty absorbing this equipment into its armed forces.”

The Los Angeles class submarine USS Santa Fe transits in formation on the surface with Royal Australian Navy Collins class submarines HMAS Collins, HMAS Farncomb, HMAS Dechaineux, and HMAS Sheean in the West Australian Exercise Area in February 2019. Australian Department of Defense

The fact that the planned Australian deal will bring more SURTASS systems to the Asia Pacific region will clearly bring benefits to U.S. and other allied anti-submarine capabilities, too, while the ability to potentially deploy these systems on different vessels will only help with coverage and being able to deploy them with greater flexibility — and unpredictability.

The growing submarine threat posed by both China and Russia is something that U.S. officials have been very vocal about. Both countries are working to expand their submarine fleets and are developing more advanced nuclear-powered and diesel-electric designs that are quieter and therefore harder to detect.

For Australia, the threat posed by Chinese submarines, and the expanding size and capabilities of the People’s Liberation Army Navy (PLAN), more generally, is at the center of current military modernization initiatives.

The nature of the Chinese maritime threat to Australia has been made more manifest in recent times, with high-profile incidents both close to the Australian coast and in the hotly contested South China Sea.

In May last year, Australian officials reacted angrily to the appearance of a PLAN intelligence-gathering vessel off the coast of Australia. Although the Type 815 Dongdiao spy ship Haiwangxing apparently remained in international waters throughout the incident, Australia’s then Defense Minister Peter Dutton described the actions of the PLAN vessel as an “aggressive act.”

An official Australian Department of Defense photo of the Type 815 Dongdiao class auxiliary intelligence ship, or AGI, Haiwangxing operating off the northwest shelf of Australia in May 2022. Australian Department of Defense

Significantly, the route of the Haiwangxing down Australia’s west coast seems to have brought it close to the Naval Communication Station Harold E. Holt, or HEHCS, a joint Australian and U.S. naval communication station. This highly sensitive installation provides very low frequency (VLF) radio communications that are vital for operations by Australian, U.S., and allied submarines operating in the western Pacific Ocean and the eastern Indian Ocean.

A month later, in June 2022, a Royal Australian Air Force (RAAF) P-8A was damaged by countermeasures launched by a Chinese J-16 Flanker fighter jet over the South China Sea, according to the Australian Department of Defense. The department accused the crew of the J-16 of conducting a “dangerous maneuver” while the P-8 was operating over international waters. China’s Ministry of National Defense responded by saying the P-8 had “seriously threatened China’s sovereignty and security and the countermeasures taken by the Chinese military [were] professional, safe, reasonable, and legitimate.”

A RAAF P-8A Poseidon maritime patrol aircraft. Australian Department of Defense

These episodes bring into sharper focus the military and strategic challenges to Australia posed by China. As part of a more robust maritime posture, the Australian military is set to work increasingly closely with the United States and the United Kingdom under the AUKUS agreement, as well as to introduce the aforementioned nuclear-powered submarines.

Australian officials have specifically pointed to the growing maritime challenge from China as the driving force behind the nuclear-powered submarine program. Last year, Australia’s then Defense Minister Peter Dutton said that the RAN’s current “diesel-electric submarines would not be able to compete against the Chinese in the South China Sea beyond 2035.”

As well as these submarines, Australia is also working on developing extra-large drone submarines and, late last year, unveiled the Ghost Shark testbed that will help inform these future designs. Under the overarching Extra Large Autonomous Undersea Vehicle (XL-AUV) program, Australia is seeking to rapidly produce an affordable, autonomous, long-endurance drone that can be tailored for a variety of military and non-military missions. Ultimately, drone submarines are expected to undertake “dull, dirty, and dangerous missions” in support of crewed submarines.

The Ghost Shark testbed that will be used to develop the RAN’s future extra-large drone submarine. Anduril Australia

However advanced, hunter-killer submarines are only as effective as the targeting information available to them. By acquiring the SURTASS-E system, the Royal Australian Navy will be in a better position to get the most out of these submarines, as well as greatly enhancing its anti-submarine warfare capabilities in a broader sense.

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