In mid-2017 the U.S. Army ordered $270 million worth of components for upgrading M1A2 tanks to the new SEP3 standard as well as upgrading more M1A2SEPs to the SEP2 level. These upgrades keep the M1, or at least some of them, competitive with more recently designed and built tanks. The U.S. (mainly the army) has about a thousand of the SEP2 upgrade M1A2s and wants to up to half of that upgraded to SEP3 by 2020, the earliest date for the M2A3 upgrade will show up. That one will have major upgrades to the tank software and whatever upgrades are available for the engine, armor and electronics. A major upgrade is adding the capability to use advanced (some guided missiles) from the 120mm smooth bore gun. There may also be an ADS (Active Defense System) added as well. The specifics of M1A3 are vague because much of the tech is still in development or getting its first combat experience. What isn’t ready in the early 2020s can be added with the M1A3SEP.
The first M1A2SEP (System Enhancement Package) was developed in the late 1990s and upgraded the armor and a few other minor fixes. There were other urban warfare upgrades, because of what was encountered after 2003 in Iraq. This was called TUSK (Tank Urban Survival Kit) and evolved into the SEP2 upgrade. TUSK was installed on hundreds of tanks headed for Iraq as well as several hundred more M1s that had battle damage repaired and TUSK upgrades installed at the same time.
TUSK that entered service in 2007 with reactive armor panels for the side and rear of the tank, to provide added protection from RPGs. A slat armor panel protects the engine exhaust outlet of the tank from RPGs. A 1.5 ton belly armor kit, which can be installed in two hours, provides additional protection from mines and large bombs. Enhancements also include night vision for all crew members. There is also a telephone added to the side of the tank, so that infantry can more easily communicate with the crew when the tank is "buttoned up" (all hatches closed). The complete TUSK kit costs about $500,000 each and takes about twelve hours to install all the components. Later additions to TUSK included a rear-view camera for the driver and RWS (remote weapons station) so the commanders .50 caliber (12.7mm) machine-gun could be operated from inside the tank. This was particularly useful if the tank is taking a lot of small arms fire.
The M1A2SEP2 made most of the TUSK items standard and added the RWS for the 12.7mm machine-gun as standard, as well in computer hardware (including color flat screen displays) and software (including a new operating system) improved TUSK ERA (explosive reactive armor), making the external phone standard and upgrading the transmission to make it more reliable.
The SEP3 that enters service in 2017 includes more improvements in the TUSK armor and RWS, an electricity generation and distribution (for all the electronic gadgets that need recharging or whatever), upgraded communications and networking, installation of VHMS (Vehicle Health Management System) and the use of LRMs (Line Replaceable Modules) to make it easier to upgrade or repair problems. The new communications features include ADL (Ammunition DataLink) to use airburst rounds, improved counter-IED armor package. An upgraded FLIR (night vision heat sensor and an APU (Auxiliary Power Unit) under armor to run electronics while stationary instead of the engine.
So far, over 10,000 American M1 tanks have been produced and most of them subsequently updated at least once (mainly in the 1990s). In 2012 the army, seeking to save a billion dollars, sought to close the Lima (Ohio) plant that builds and modifies the M1. The closure would be for three years, and when it was reopened there would be a backlog of upgrades and parts orders to fill to keep the plant open until, perhaps, an M1 replacement comes along. At the time the Department of Defense did not have any firm plans for an M1 replacement and still doesn’t.
Politicians and the operators of the plant worked hard to keep the plant open in order to save jobs, votes, and operating profits. This is basically a largely political decision that involves getting the money (from the taxpayers) to stay open by pretending that the army wants this. But the army leadership openly opposed this plan. The army lost and the plant remained open, mainly doing upgrades.
There was never any doubt that the Lima plant will eventually be needed because the army is planning to maintain its M1 tank fleet (some 7,000 of them) into the 2030s. The M1 has already been in service since the 1980s and may become the first MBT (main battle tank) design to stay in service for half a century. Technically, some World War II tanks achieved that dubious goal but not in the service of a major power.
The electronics on the M1 have undergone several upgrades so far, in addition to the larger main gun. More equipment has been added for urban warfare (an outside phone, cameras, reactive armor side panels, thermal sights, and shields for the external machine-guns) and new ammo types for the main gun have been developed. A major enhancement was depleted uranium armor, which made the M1 virtually invulnerable from the front.
The one remaining item in need of improvement is the 1,500 horsepower gas turbine engine. Improvements here included electronic monitors on many engine components, an electronic logbook (to record all pertinent engine activity), and a maintenance program that makes the most of all this data. If the engine is monitored closely and constantly, it's possible to carry out maintenance in a more timely (before something fails) manner. The army would also like to develop an improved (more efficient and less expensive to maintain) engine, but that is also a costly item they can't afford at the moment.
New anti-tank weapons are always being developed and the army wants to at least be able to afford new gear to deal with new threats. One threat that is currently ignored is top attack warheads (that put a shape charge type attack against the thin top armor). There are also new types of mines and electronic threats. If the M1 is to survive for half a century it will have to evolve, as well as endure.
The M1 Abrams tank is considered the best combat proven tank in the world. But there are many different models of M1s, which vary considerably in their combat capability. The earliest model is only about half as capable as the M1A2 SEP model. The first of 3,273 M1 Abrams tanks was produced in 1978. This version had a 105mm gun. The first of 4,796 M1A1s (with a 120mm gun and depleted uranium armor) was produced in 1985 (plus 221 for the U.S. Marines, 555 co-produced with Egypt and another 200 M1A1s for Egypt). Production of the M1A2 (with improved fire control systems) began in 1986, with 77 for the US Army, 315 for Saudi Arabia, and 218 for Kuwait. Another 600 M1s were upgraded to M1A2 standards. Deliveries of these upgrades began in 1998. In 2001 the army began to upgrade 240 M1A2 tanks with better thermal imaging and fire control equipment as well as communications and computer equipment that would allow tanks to operate a full color "battlefield internet" with each other, as well as headquarters and warplanes with similar equipment. By 2013 the army had upgraded 700 tanks to the M1A2SEP standard and built another 240 new M1A2SEP vehicles. The goal is to get at least 2,000 upgraded to M1A2SEP or higher by 2020.