View source for AN/SLQ-25 Nixie

{{Short description|American towed torpedo decoy system}}
{{Use american english|date=June 2025}}
{{Use dmy dates|date=June 2025}}
[[Image:SLQ-25 Nixie aboard USS Iowa (BB-61).jpg|thumb|right|SLQ-25 Nixie aboard {{USS|Iowa|BB-61|6}}]]
[[File:TB-14A.png|thumb|TB-14A towed decoy, from the AN/SLQ-25A/C "Nixie" system]]
The '''AN/SLQ-25 Nixie''' and its variants are towed [[sonar decoy|torpedo decoy]]s used on [[United States|US]] and allied [[warships]]. It consists of a towed decoy device (TB-14A) and a shipboard signal generator. The Nixie is capable of defeating [[Wake homing|wake-homing]], [[Acoustic homing|acoustic-homing]], and wire-guided [[Torpedo|torpedoes]]. The decoy emits signals to draw a torpedo away from its intended target.

The Nixie attempts to defeat a torpedo's passive sonar by emitting simulated ship noise—such as propeller and engine noise—or defeat a torpedo's active sonar by amplifying and returning its pings.<ref>{{Cite web |title=AN/SLQ-25 NIXIE |url=https://man.fas.org/dod-101/sys/ship/weaps/an-slq-25.htm |access-date=2022-05-18 |website=FAS Military Analysis Network.org}}</ref> Typically, larger ships may have two Nixie systems mounted at the stern of the ship to allow operation singularly or in pairs while smaller ships may have only one system.

In accordance with the [[Joint Electronics Type Designation System]] (JETDS), the "''AN/SLQ-25''" designation represents the 25th design of an Army-Navy electronic device for waterborne countermeasures special equipment. The JETDS system also now is used to name all [[Department of Defense]] electronic systems.

== Variants ==
The AN/SLQ-25A was introduced in 1987.<ref>{{Cite web |last= |date=2002-12-18 |title=Sensytech Receives Two Contracts For Torpedo Defense System |url=https://www.defense-aerospace.com/sensytech-wins-torpedo-defense-deal-dec-19/ |access-date=2023-06-17 |website=Defense aerospace}}</ref> It is a clean-sheet design when compared to the original AN/SLQ-25 Nixie. Apart from a few minor mechanical components, they share no common parts. The AN/SLQ-25A utilises a fiber optic tow cable (FOTC) and a {{convert|10|hp|adj=on}} RL-272C double drum winch. Several engineering changes resulted in [[commercial off-the-shelf]] (COTS) equipment being utilised extensively in the system. A diagnostic program can be initiated locally or from the remote control station, and tests all electronic functions. The AN/SLQ-25A provides improved deceptive [[Electronic countermeasure#Infrared and acoustic analogies|countermeasures]] capability over the original Nixie.<ref name=":0">{{Cite web |last=Archus |first=Dorian |date=2020-12-26 |title=US Navy selects Ultra for NIXIE electro-acoustic towed torpedo countermeasure system - Naval Post- Naval News and Information |url=https://navalpost.com/us-navy-selects-ultra-for-nixie-electro-acoustic-towed-torpedo-countermeasure-system/ |access-date=2023-06-17 |language=en-US}}</ref><ref name=":1">{{Cite web |title=AN/SLQ-25 NIXIE |url=https://man.fas.org/dod-101/sys/ship/weaps/an-slq-25.htm |access-date=2023-06-17 |website=FAS Military Analysis Network.org}}</ref>

The AN/SLQ-25B variant includes equipment of the AN/SLQ-25A and introduced a towed array sensor to detect submarines and incoming [[Torpedo|torpedoes]]. It also includes a fiber optic display LAN. Previous versions could only simulate ship noise and were effective against passive homing torpedoes but ineffective against active homing torpedoes; the AN/SLQ-25B added the ability to defeat active homing torpedoes by intercepting, amplifying, and returning the sonar pings from the incoming torpedo.<ref>{{Cite web |last= |first= |date=2005-06-30 |title=$20.5M for 3 More NIXIE Torpedo Decoy Systems |url=http://www.defenseindustrydaily.com/205m-for-3-more-nixie-torpedo-decoy-systems-0779/ |access-date=2023-06-17 |website=Defense Industry Daily}}</ref><ref name=":0" /><ref name=":1" />

The AN/SLQ-25C was first procured in 2007 and is a general electronics upgrade of the AN/SLQ-25A. The AN/SLQ-25C has additional countermeasure modes, more reliable power amplification, a new COTS signal generator, and a longer, more functional littoral fiber optic tow cable (LFOTC) for operation in shallow water.<ref>{{Cite web |date=March 2023 |title=Department of Defense: Fiscal Year (FY) 2024 Budget Estimates |url=https://media.defense.gov/2023/Mar/29/2003188820/-1/-1/0/SCN_BOOK.PDF |access-date=2023-06-17 |publisher=[[United States Department of Defense]]}}</ref><ref name=":1" /><ref name=":2">{{Cite web |last= |first= |date=2009-08-26 |title=$48.5M to Alion for Torpedo Detection System RD and Testing |url=http://www.defenseindustrydaily.com/485m-to-alion-for-torpedo-detection-system-rd-and-testing-05740/ |access-date=2023-06-17 |website=Defense Industry Daily}}</ref>

The AN/SLQ-25D was a planned upgrade with a contract awarded in 2009.<ref>{{Cite web |date=2009-06-01 |title=U.S. Navy Awards Argon ST $6.2 Million to Upgrade Its Surface Ship Torpedo Defense Program |url=https://www.argonst.com/news/press_releases/2009/SSTD_Release_1_June_2009.htm |access-date=2023-06-17 |website=ArgonST}}</ref> It was to feature an [[open architecture]], allowing it to serve as a host to other systems and support their information gathering and threat detection.<ref name=":2" /> In 2012, the AN/SLQ-25D program became a part of the Surface Ship Torpedo Defense (SSTD) program, a US Navy effort to field a system that could detect and destroy incoming torpedoes. The AN/SLQ-25D was redesignated as the AN/SLQ-25X, and it was intended to be the tow point for the torpedo detection sensors.<ref>{{Cite web |last=Rockwell |first=David |date=2018-08-01 |title=Submarine Sonar Systems |url=https://tealgroup.com/index.php/component/zoo/item/submarine-sonar-systems |access-date=2023-06-17 |website=Teal Group}}</ref> However, the Navy canceled the SSTD program and with it the AN/SLQ-25X in 2018.<ref>{{Cite web |title=Surface Ship Torpedo Defense (SSTD) System: Torpedo Warning System (TWS) and Countermeasure Anti-Torpedo (CAT) |url=https://www.dote.osd.mil/Portals/97/pub/reports/FY2018/navy/2018sstd_tws_cat.pdf?ver=2019-08-21-155651-040 |access-date=2023-06-17 |publisher=[[Director, Operational Test and Evaluation|The Office of the Director, Operational Test and Evaluation]]}}</ref>

In place of the canceled AN/SLQ-25X, AN/SLQ-25E procurement began in 2022. The AN/SLQ-25E addresses obsolescence issues with previous AN/SLQ-25 variants by updating the hardware and software to a COTS-based, modular, and open architecture. The AN/SLQ-25E has improved capability against [[Wake homing|wake-homing]], [[Acoustic homing|acoustic-homing]], and wire-guided torpedoes. All existing AN/SLQ-25 units are being upgraded to the AN/SLQ-25E baseline.<ref>{{Cite web |title=Justification Book |url=https://www.dacis.com/budget/budget_pdf/FY20/PROC/N/2213_41.pdf |access-date=2023-06-17 |publisher=[[United States Department of the Navy|Department of the Navy]] |pages=1–2}}</ref>

== Further development ==
Under a joint UK/US [[memorandum of understanding]], the UK [[Ministry of Defence (United Kingdom)|MoD]] and the US [[United States Department of Defense|DoD]] are furthering torpedo survivability systems. The US is currently{{when|date=January 2025}} working on an Active Source program called the [[DCL Technology Demonstrator programme]], and the UK has developed and entered into service the [[SSTD|S2170 Surface Ship Torpedo Defence]] system.

An improved torpedo countermeasure system called the AN/SLQ-61 Lightweight Tow (LWT) Torpedo Defense Mission Module (TDMM) is lighter than the AN/SLQ-25 and has a different tow profile, making it more suited for small combatant warships operating in littoral environments. The LWT is a modular, digitally controlled soft kill countermeasure decoy that can defend ships against wake-homing, acoustic-homing, and wire-guided torpedoes.<ref>[https://www.navyrecognition.com/index.php/news/defence-news/2018/may-2018-navy-naval-defense-news/6197-u-s-navy-completes-lightweight-torpedo-defense-mission-module-testing.html U.S. Navy Completes Lightweight Torpedo Defense Mission Module Testing]. ''Navy Recognition''. 5 May 2018.</ref>

==References==
{{reflist}}

==See Also==
{{Portal|Electronics}}
*[[List of military electronics of the United States]]

==External links==
*{{youtube|id=VeRJN4U0nOM|title=Inside Battleship New Jersey’s Nixie Room}}

{{Electronic warfare navbox}}

[[Category:Sonar decoys]]
[[Category:Anti-submarine warfare]]
[[Category:Military electronics of the United States]]
[[Category:Weapons countermeasures|Nixie]]
[[Category:Electronic countermeasures]]
[[Category:Electronic warfare equipment]]