Editing M1 Abrams (section)

===Countermeasures===

====Camouflage====
[[File:M1A1 Twin Bridges training area 2C Republic of Korea 1-23 Infantry.jpg|thumb|left|U.S. M1A1s during the [[Foal Eagle]] 1998 training exercises in South Korea, with their factory single green paint scheme]]
{{further|Military camouflage}}

Some XM1 FSED pilot vehicles and XM1 LRIP tanks were painted with the [[MERDC camouflage|Mobility Equipment Research and Design Command]] (MERDC) 4-color paint scheme.{{sfn|Zaloga|2019|p=6}} Factory-applied [[forest green]] paint gave way to "Europe 1", a three-color pattern, in 1983 at the same time as [[Chemical Agent Resistant Coating]] (CARC) was adopted. Europe 1 consisted of Green 383, Brown 383, and black colors.{{sfn|Zaloga|2019|p=7}}

U.S. Army Abrams deployed to the Iraq War were painted Carc Tan 686A.{{sfn|Zaloga|2019|p=22}} Due to the increasing significance of American operations in Europe, the U.S. Army transitioned most of its vehicles to CARC Green 383 starting around 2017.{{sfn|Zaloga|2019|p=32}}

M1A1s came from the factory with the NATO three color camouflage Black/Med-Green/Dark-Brown CARC paint jobs.{{Citation needed|date=April 2008}} Today, M1A1s are given the NATO three color paint job during rebuilds. M1s and M1A1s deployed to Operation Desert Storm were hastily painted [[desert tan]]. Some, but not all, of these tanks were repainted to their "authorized" paint scheme. M1A2s built for Middle Eastern countries were painted in desert tan. Replacement parts (roadwheels, armor skirt panels, drive sprockets, etc.) are painted olive green, which can sometimes lead to vehicles with a patchwork of green and desert tan parts.

[[File:Armoured vehicles parading through Darwin on 25 April 2015.jpg|thumb|right|M1A1 in the Australian Army's Disruptive Pattern Camouflage, used for vehicles and [[materiel]].]]
Australian M1A1s are camouflaged in AUSCAM, a scheme that consists of black, olive drab, and brown.{{sfn|Zaloga|2019|p=40}}

====Concealment====
The turret is fitted with two six-barreled [[M250 grenade launcher|M250]] [[smoke grenade]] launchers (USMC M1A1s used an eight-barreled version), with one on each side. When deployed, the grenades [[Air burst|airburst]], creating a thick smoke that blocks both visual and [[Thermography|thermal imaging]]. The engine is also equipped with a vehicle engine exhaust smoke system (VEESS) that is triggered by the driver. When activated, fuel is sprayed into the hot turbine exhaust, creating thick smoke. This system was discontinued by the U.S. Army after it switched to JP-8 jet fuel in the 1990s{{sfn|Green|Stewart|2005|p=62-65}} due to the risk of fire.{{citation needed|date=January 2024}}<!-- Are the Intellitec Multisalvo M6 smoke grenade launchers worth mentioning?{{Sfn|Green|Stewart|2005|p=105}}-->

====Armor====
{{further|Chobham armor}}
{{multiple image
| perrow            = 2
| total_width       = 300
| image1            = M1 Abrams Hull Front Special Armor.jpg
| image2            = M1 Abrams Turret Bustle Side Special Armor.png
| image3            = M1 Abrams Hull Side Special Armor.jpg
| image4            = M1 Abrams Gun Shield Special Armor.jpg
| footer            = Configuration of M1 Abrams Chobham Special Armor. Clockwise from the top left: hull front, turret bustle side, gun shield, hull side.
}}
[[File:M1A Abrams im Taunus.jpg|thumb|Tankers drive an M1A1 Abrams through the [[Taunus|Taunus Mountains]] north of [[Frankfurt]], [[Germany]] during Exercise Ready Crucible in February 2005.]]
[[File:Trident Juncture 18 - U.S. Marines advance on Folldal 4871351.jpg|thumb|U.S. Marines with the 2nd Tank Battalion, [[2nd Marine Division (United States)|2nd Marine Division]], advance on their eastern objective defended by opposing [[Spanish Army|Spanish forces]] during [[Exercise Trident Juncture 2018|Exercise Trident Juncture]] 18 near Dalholen, [[Norway]], 3 November 2018.]]

In addition to conventional [[rolled homogeneous armor]] (RHA), the Abrams uses a secret British-developed Chobham [[composite armor]].

The M1 Abrams composite armor (referred to as "special armor" by the U.S. Army){{sfn|Green|Stewart|2005|p=18}} is most substantial at the front of the hull, where it is {{convert|2|feet}} at its thickest.{{sfn|Green|Stewart|2005|p=102}} The front of the hull is armored with composites. The Abrams turret features composite armor across both the front and the sides.<ref name="Special Armor classification">{{cite report |author1=PEO Close Combat Vehicles |title=Special Armor Security Classification Guide |date=16 February 1988 |url=https://static.warthunder.ru/upload/files/CIA-RDP91B00390R000300220014-8_18526c536b61b903b78d1571c3476c70.pdf |access-date=1 January 2024 |archive-date=28 December 2023 |archive-url=https://web.archive.org/web/20231228070557/https://static.warthunder.ru/upload/files/CIA-RDP91B00390R000300220014-8_18526c536b61b903b78d1571c3476c70.pdf |url-status=dead }}</ref>

The armor is much thicker on the Abrams than on previous tanks. This is not a reflection of any weakness of Chobham armor—pound-for-pound Chobham is better at stopping shaped charges and kinetic projectiles. Rather, unlike RHA, Chobham is optimized against shaped charge projectiles. Effective shaped charges, particularly [[anti-tank guided missiles]], were a relatively new battlefield innovation. Lacking a breakthrough advance in novel armor material to negate shaped charges, previous tank designers had simply not found it practical to add the amount of RHA required to defeat shaped charges.{{sfn|Kelly|1989|pp=111–140}}

While the exact composition of the Abrams' composite armor remains a state secret, a generalization about how it works can be gleaned from what has been publicly said about it. It consists of ceramic blocks set in resin between layers of conventional armor.{{sfn|Green|Stewart|2005|p=96-97}}{{refn|group=nb|name=Chobham|Chobham could also incorporate nylon micromesh and/or [[titanium]]<ref>{{cite news |last1=Hambling |first1=David |title=Breakthrough ballistics |url=https://www.theguardian.com/science/2001/oct/11/physicalsciences.technology |access-date=1 January 2024 |work=The Guardian |date=11 October 2001}}</ref>}}{{sfn|Zaloga|2019|p=6}} The ceramic acts as a [[non-explosive reactive armor]] (NERA), disrupting [[shaped charge]]s. The NERA plates shatter on impact with the projectile, disrupting the penetrating jets of shaped charges; or in the case of kinetic rounds eroding the projectile.{{sfn|Green|Stewart|2005|p=96-97}}

For the M1 Abrams base model, military historian [[Steven Zaloga]] estimates the frontal armor at 350&nbsp;mm vs APFSDS and 700&nbsp;mm vs HEAT warhead in the book, ''M1 Abrams Main Battle Tank 1982–1992'' (1993).<ref>{{harvnb|Zaloga|Sarson|1993|pp=9–10}}: Zaloga gives another set of figures in this book {{convert|350|mm|abbr=on}} against APFSDS and {{convert|700|mm|abbr=on}} vs HEAT.</ref> In ''M1 Abrams vs T-72 Ural'' (2009), he uses Soviet estimates of {{convert|470|mm|abbr=on}} vs APFSDS and {{convert|650|mm|abbr=on}} vs HEAT for the base model Abrams. He also gives the Soviet estimates for the M1A1, {{convert|600|mm|abbr=on}} vs APFSDS, and {{convert|700|mm|abbr=on}} vs HEAT.<ref name="T-72vsM1">{{harvnb|Zaloga|2009|p=15}}: Author mentions that a Soviet report estimated the protection of the basic M1 to be equivalent to {{convert|470|mm|abbr=on}} steel armor against armor-piercing rounds and equivalent to {{convert|650|mm|abbr=on}} steel armor against shaped charge warheads.</ref>

Armor protection against [[Kinetic energy penetrator|kinetic energy rounds]] was improved by implementing a new special armor incorporating [[depleted uranium]] (DU). This was introduced into the M1A1 production starting October 1988.{{sfn|Hunnicutt|2015|p=245}} but at the expense of adding considerable weight to the tank, as depleted uranium is 1.7&nbsp;times denser than [[lead]].<ref>{{cite news |url=http://news.bbc.co.uk/2/hi/in_depth/2860759.stm |title=BBC: US to use depleted uranium |work=BBC News |date=18 March 2003 |access-date=9 June 2009 |url-status=live |archive-url=https://web.archive.org/web/20090519090657/http://news.bbc.co.uk/2/hi/in_depth/2860759.stm |archive-date=19 May 2009}}</ref> The DU is applied to the backing plate of the turret armor arrays.

The first M1A1 tanks to receive this upgrade were tanks stationed in Germany. US-based tank battalions participating in Operation Desert Storm received an emergency program to upgrade their tanks with depleted uranium armor immediately before the onset of the campaign. M1A2 tanks uniformly incorporate depleted uranium armor, and all M1A1 tanks in active service have been upgraded to this standard as well.<ref name="Clancy">{{cite book |last1=Clancy |first1=Tom |title=Armoured Warfare: A Guided Tour of an Armoured Cavalry Regiment |date=1996 |publisher=HarperCollins |location=London |isbn=978-0-00-255525-8 |page=58 |url=https://archive.org/details/armouredwarfareg0000clan |access-date=1 January 2024}}</ref> This variant was designated as the M1A1HA (HA for Heavy Armor).<ref name="Zaloga_Sarson_11">{{harvnb|Zaloga|Sarson|1993|p=11}}</ref>

The M1A1 AIM, M1A2 SEP and all subsequent Abrams models feature depleted uranium.<ref>{{Cite journal|date=August 2006|title=The Army's Future Combat Systems Program and Alternatives |url=https://www.cbo.gov/sites/default/files/cbofiles/ftpdocs/74xx/doc7461/08-02-army.pdf |archive-url=https://ghostarchive.org/archive/20221009/https://www.cbo.gov/sites/default/files/cbofiles/ftpdocs/74xx/doc7461/08-02-army.pdf |archive-date=2022-10-09 |url-status=live|journal=Congressional Budget Office Study|page=67}}</ref> Each Abrams variant after the M1A1 have been equipped with depleted uranium armor of different generations. The M1A1HA uses first-generation armor, while the M1A2 and M1A1HC use second generation depleted uranium. The M1A2 SEP variants have been equipped with third-generation depleted uranium armor combined with a graphite coating.

For the M1A1HA, Zaloga gives a frontal armor estimate of {{convert|600|mm|abbr=on}} vs APFSDS and {{convert|1300|mm|abbr=on}} vs HEAT in ''M1 Abrams Main Battle Tank 1982–1992'', nearly double the original protection of the Abrams.<ref name="Zaloga_Sarson_11" /> In ''M1 Abrams vs T-72 Ural'', he uses different estimates of {{convert|600|mm|abbr=on}} vs APFSDS and {{convert|700|mm|abbr=on}} vs HEAT for the front hull and {{convert|800|mm|abbr=on}} vs APFSDS and {{convert|1300|mm|abbr=on}} vs HEAT for the front of the turret.<ref name="T-72vsM1" /> The protection of M1A2 SEP is a frontal turret armor estimate of {{convert|940-960|mm|abbr=on}} vs APFSDS and {{convert|1320-1620|mm|abbr=on}} vs HEAT, glacis estimate of {{convert|560-590|mm|abbr=on}} vs APFSDS and {{convert|510-1050|mm|abbr=on}} vs HEAT, and lower front hull estimate of {{convert|580-650|mm|abbr=on}} vs APFSDS and {{convert|800-970|mm|abbr=on}} vs HEAT. The M1A2 SEPv3 increased the LOS thickness of the turret and hull front armor; total armor protection from this increase is not known.<ref name=autogenerated1/>

In 1998, a program was begun to incorporate improved hull, turret, and side armor into the M1A2. This was intended to offer better protection against rocket-propelled grenades that were more modern than the baseline RPG-7. These kits were installed on about 325 older M1A2 tanks in 2001–2009 and were also included in upgraded tanks.{{sfn|Zaloga|Sarson|1993|p=48}}

[[File:Abrams XM32 tile installation.jpg|thumb|right|A U.S. Army M1A1 with XM32 tiles instead of XM19 reactive armor in 2017]]
The Abrams may also be fitted with explosive [[reactive armor]] over the track skirts if needed (such as the Tank Urban Survival Kit)<ref name=Army_TUSK_upgrades/> and [[slat armor]] over the rear of the tank and rear fuel cells to protect against [[Anti-tank missile|ATGMs]].

The 105&nbsp;mm M1 Abrams does not use [[spall liner]]s, though three 105&nbsp;mm rounds on the turret basket floor are covered with [[spall]] protection covers on the M1 tank variant.<ref>{{cite book |last1=Green |first1=Michael |title=M1 Abrams Main Battle Tank: The Combat and Development History of the General Dynamics M1 and M1A1 Tanks |date=1992 |publisher=Motorbooks International |isbn=0-87938-597-9 |pages=42, 67 |url=https://archive.org/details/m1abramsmainbatt0000gree/page/66/mode/2up?q=spall |access-date=28 December 2023}}</ref>

====Damage control====
The tank has a [[gaseous fire suppression|halon firefighting]] system to automatically extinguish fires in the crew compartment. The engine compartment has a firefighting system that is engaged by pulling a T-handle located on the left side of the hull. The Halon gas can be dangerous to the crew.<ref>{{cite web |url=https://www.cdc.gov/niosh/npg/npgd0634.html |title=NIOSH Pocket Guide to Chemical Hazards |publisher=CDC |url-status=live |archive-url=https://web.archive.org/web/20170818091459/https://www.cdc.gov/niosh/npg/npgd0634.html |archive-date=18 August 2017}}</ref> However, the toxicity of [[Halon 1301]] gas at 7% concentration is much lower than the combustion products produced by fire in the crew compartment, and CO<sub>2</sub> dump would be lethal to the crew.<ref name="The_Chieftain">{{Citation|last=The_Chieftain|title=Chieftain Chats Abrams|date=14 October 2018 |url=https://www.youtube.com/watch?v=aladW_D4nKU|access-date=21 February 2019|archive-date=14 October 2018|archive-url=https://web.archive.org/web/20181014180752/https://www.youtube.com/watch?v=aladW_D4nKU&gl=US&hl=en |url-status=live}}</ref>

The crew compartment also contains small hand-held [[fire extinguisher]]s. Fuel and ammunition are stored in armored compartments with [[blowout panel]]s intended to protect the crew from the risk of the tank's own ammunition [[cooking off]] (exploding) if the tank is damaged. The main gun's ammunition is stored in the rear section of the turret, with blast doors that open under power by sliding sideways only to remove a round for firing, then automatically close. Doctrine mandates that the ammunition door must be closed before arming the main gun.<ref name="The_Chieftain"/>

====NBC protection====
Starting with the M1A1 variant [[CBRN defense|nuclear, biological, chemical]] protection was provided by a turret [[Overpressure (CBRN protection)|overpressure]] system. Previously the Abrams crew had been required to don [[NBC suit]]s in case of an NBC attack. NBC masks are still retained as a backup, and crews often train while wearing them to remain proficient and combat-effective in such a scenario.<ref name="M1 Tank Story">{{cite news |last1=Lett |first1=Philip W. |title=The M1 Tank Story |work=Marine Corps Gazette |agency=U.S Marine Corps |issue=August 1991}}</ref>

====Tank Urban Survival Kit====
[[File:OCPA-2005-03-09-165522.jpg|thumb|left|An M1A2 with TUSK]]

The Tank Urban Survival Kit (TUSK) is a series of improvements to the M1 Abrams intended to improve fighting ability in urban environments.<ref name=Army_TUSK_upgrades>{{cite web |url=https://www.army.mil/article/7495/modified-m1-a2-abrams-tanks-improve-safety-precision |title=Modified M1-A2 Abrams Tanks Improve Safety, Precision |date=19 February 2008 |access-date=22 July 2017 |url-status=live |archive-url=https://web.archive.org/web/20130515232734/http://www.army.mil/article/7495/modified-m1-a2-abrams-tanks-improve-safety-precision |archive-date=15 May 2013}}</ref> Historically, urban and other close battlefields have been poor places for tanks to fight. A tank's front armor is much stronger than that on the sides, top, or rear. In an urban environment, attacks can come from any direction, and attackers can get close enough to reliably hit weak points in the tank's armor or gain sufficient elevation to hit the top armor.

Armor upgrades include reactive armor on the sides of the tank and [[slat armor]] on the rear to protect against [[rocket-propelled grenade]]s and other shaped charge warheads.{{sfn|Green|Stewart|2005|p=93}} Abrams Reactive Armor Tile (ARAT) I consists of 32 XM19 reactive armor boxes added to the sides of the tank. ARAT II consists of rounded XM32 reactive armor tiles mounted over-top the XM19 tiles.{{sfn|Zaloga|2019|p=24-25}} A [[Transparent Armor Gun Shield]] and a thermal sight system are added to the loader's top-mounted M240B 7.62&nbsp;mm machine gun,{{sfn|Zaloga|2019|p=24-25}} and a [[Kongsberg Gruppen]] Remote Weapon Turret carrying a 12.7&nbsp;mm (.50 in) caliber machine gun (again similar to that used on the Stryker) is in place of the tank commander's original 12.7&nbsp;mm (.50 in) caliber machine gun mount, wherein the commander had to expose himself to fire the weapon manually. An exterior [[telephone]] allows supporting infantry to communicate with the tank commander.{{sfn|Zaloga|2019|p=24-25}}

[[File:M1A1 Abrams with Integrated Management System new Tank Urban Survivability Kit Dec. 2007.jpg|thumb|An M1A1 Abrams with an Abrams Integrated Management System (AIM) and the Tank Urban Survivability Kit (TUSK) conducting a patrol in Baghdad, 2007.]]
In August 2006, General Dynamics Land Systems received a U.S. Army order for 505 Tank Urban Survivability Kits (TUSK) for Abrams main battle tanks supporting operations in Iraq, under a US$45&nbsp;million contract. Deliveries were expected to be completed by April 2009.<ref name="TUSK_def_update">{{cite web |url=http://defense-update.com/products/t/tusk.htm|title=Tank Urban Survivability Kit (TUSK)|access-date=11 October 2014 |url-status=dead|archive-url=https://web.archive.org/web/20141013121147/http://defense-update.com/products/t/tusk.htm |archive-date=13 October 2014}}</ref> Under a separate order, the U.S. Army awarded General Dynamics Armament and Technical Products (GDATP) US$30 million to produce reactive armor kits to equip M1A2s.<ref name="TUSK_def_update" />

Tiles will be produced at the company's reactive armor facility in Stone County Operations, [[McHenry, Mississippi]]. In December 2006, the U.S. Army added Counter Improvised Explosive Device enhancements to the M1A1 and M1A2 TUSK, awarding GDLS $11.3&nbsp;million contract, part of the $59&nbsp;million package mentioned above. In December, GDLS also received an order, amounting to around 40% of a US$48&nbsp;million order, for loader's thermal weapon sights being part of the TUSK system improvements for the M1A1 and M1A2 Abrams Tanks.<ref name="TUSK_def_update" />

====Active protection system====
In addition to the armor, some USMC Abrams tanks were equipped with a [[Active protection system#Soft-kill measures|soft-kill active protection system]], the AN/VLQ-6 Missile Countermeasure Device (MCD) that can impede the function of guidance systems of some semi-active control line-of-sight ([[SACLOS]]) [[wire-guided missile|wire]]- and [[command guidance|radio guided]] anti-tank missiles (such as the Russian [[9K114 Shturm]]) and [[infrared homing]] missiles. These were not ready in time for the Gulf War. The MCD works by emitting a massive, condensed infrared signal to confuse the infrared homing seeker of an [[anti-tank guided missile]] (ATGM). However, the drawback to the system is that the ATGM is not destroyed, it is merely directed away from its intended target, leaving the missile to detonate elsewhere.<ref name="ActiveDefenseCountermeasures">{{cite web |url=http://www.defense-update.com/features/du-1-04/soft-kill-west.htm |title= Active Defense & Countermeasures |publisher=Defense Update.com |date=25 April 2006 |access-date=9 June 2009 |url-status=dead |archive-url=https://web.archive.org/web/20090310041758/http://www.defense-update.com/features/du-1-04/soft-kill-west.htm |archive-date=10 March 2009}}</ref> During the Iraq War the U.S. Marine Corps equipped its M1A1s with AN/VLQ-8A electro-optical jammers.{{sfn|Green|Stewart|2005|p=107-108}}

[[File:M1A1 Trophy Technology Demonstrator.jpg|thumb|The Trophy Active Protection System (APS) was installed and tested on a USMC M1A1 Abrams in 2017.]]
In 2016, the U.S. Army and Marine Corps began testing the Israeli [[Trophy (countermeasure)|Trophy]] active protection system to protect their Abrams tanks from modern RPG and ATGM threats by either jamming (with ATGMs) or firing small rounds to deflect incoming projectiles.<ref>[https://news.usni.org/2016/04/14/walsh-marines-may-protect-tanks-with-active-and-ew-protection-systems-much-like-ship-self-defense Walsh: Marines May Protect Tanks With Active and EW Protection Systems, Much Like Ship Self-Defense] {{webarchive |url=https://web.archive.org/web/20160414131211/https://news.usni.org/2016/04/14/walsh-marines-may-protect-tanks-with-active-and-ew-protection-systems-much-like-ship-self-defense |date=14 April 2016}} – News.USNI.org, 14 April 2016</ref> The Army planned to field a brigade of over 80 tanks equipped with Trophy to Europe in 2020.<ref>[http://www.military.com/daily-news/2017/10/09/some-abrams-tanks-trophy-system-2020-army.html?ESRC=todayinmil.sm Some Abrams Tanks Will Have "Trophy" System By 2020: Army] {{Webarchive |url=https://web.archive.org/web/20171011022416/http://www.military.com/daily-news/2017/10/09/some-abrams-tanks-trophy-system-2020-army.html?ESRC=todayinmil.sm |date=11 October 2017}} – Military.com, 9 October 2017</ref> It is planned for up to 261 Abrams to be upgraded with the system, enough for four brigades.<ref>[https://breakingdefense.com/2018/05/all-armored-brigades-to-get-active-protection-systems-gen-milley/ All Armored Brigades To Get Active Protection Systems: Gen. Milley] {{Webarchive |url=https://web.archive.org/web/20180715011501/https://breakingdefense.com/2018/05/all-armored-brigades-to-get-active-protection-systems-gen-milley/ |date=15 July 2018}}. ''Breaking Defense''. 15 May 2018.</ref> In June 2018, the Army awarded [[Leonardo DRS]], U.S. partner to Trophy's designer [[Rafael Advanced Defense Systems|Rafael]], a $193 million contract to deliver the system in support of M1 Abrams "immediate operational requirements".<ref>[https://www.armytimes.com/news/2018/07/05/abrams-tanks-get-new-round-of-israeli-made-shields-to-fend-off-anti-tank-weapons/ Abrams tanks get new round of Israeli-made "shields" to fend off anti-tank weapons] {{Webarchive |url=https://web.archive.org/web/20230114043747/https://www.armytimes.com/news/2018/07/05/abrams-tanks-get-new-round-of-israeli-made-shields-to-fend-off-anti-tank-weapons/ |date=14 January 2023}}. ''Army Times''. 6 July 2018.</ref> U.S. Army M1A2 SEPv2 Abrams tanks deployed to Germany in July 2020 fitted with Trophy systems.{{cn|date=April 2025}} Deliveries to equip four tank brigades were completed in January 2021.<ref>[https://breakingdefense.com/2021/01/army-tries-again-to-protect-stryker-rafael-or-rheinmetall/ Army Tries (Again) To Protect Stryker: Rafael or Rheinmetall?] {{Webarchive |url=https://web.archive.org/web/20210111054635/https://breakingdefense.com/2021/01/army-tries-again-to-protect-stryker-rafael-or-rheinmetall/ |date=11 January 2021}}. ''Breaking Defense''. 8 January 2021.</ref>