It is the largest, fastest, and most intelligent projectile available to the US Army. Despite this you probably never heard of it nor the Army National Guard Soldiers who "pull the lanyard." If you think a 155mm howitzer shell is big, the M21 rifle is accurate, the MLRS can fire over a long distance, or that the PATRIOT air defense system is sophisticated, you are correct on all accounts.

There is one system operated by the Army National Guard however, that dwarfs any of its nearest competitors. That system is the Groundbased Midcourse Defense system and it has been operational for more than a decade with Army National Guard Soldiers from Colorado, Alaska, and California's 100th Missile Defense Brigade.

The tip of the spear for the GMD system is its Groundbased Interceptor, or simply "GBI." While it may not be the most awe-inspiring name for a defensive weapon system, its performance in conjunction with its fire control system will certainly leave you in awe. The GMD system is the ultimate "smart weapon."

The GBI consists of a 3-stage solid rocket boost vehicle which can place it's payload of an Exoatmospheric Kill Vehicle outside the earth's atmosphere. In order to do this the missile must reach an escape velocity of more than 6.9 miles per second. This hypersonic speed is several times what a 7.62mm bullet travels leaving the muzzle of a gun. To put it another way, it reaches a speed of approximately Mach 33.

Once outside the atmosphere and at distances thousands of miles from the launch facilities at Vandenberg AFB, Calif, or Fort Greely, Alaska, the boost vehicle releases the EKV on an intercept trajectory toward a hostile missile's warhead. From there, the EKV seeks out the target using multi-color sensors, a cutting-edge onboard computer, and a series of rocket motors used for independent steering in space. The EKV homes in on its target with pinpoint accuracy and destroys it using nothing more than the force of a massive collision (hit to kill) without the need of a traditional warhead or explosives. It is like hitting a bullet with a bullet, but these bullets are launched thousands of miles apart and are moving at Mach 33. It is ferociously complicated, but it works. Here's why. The GBI is just the most visible aspect to the cutting-edge GMD system. GMD is a "system of systems" involving shooters, sensors, and Command, Control and Communication systems.

While the GBIs comprise the shooter portion of the system, the sensors are the eyes and ears of GMD. These sensors consist of space-based infra-red satellites, upgraded early warning radars (UEWRs) and COBRA Dane operated by the Air Force, transportable X-band radars (AN/TPY-2), AEGIS radar on board select U.S. Navy warships, and the massive sea-based X-band Radar. These sensors provide information to the GMD Fire Control system in order to calculate precise intercept points for the GBIs and EKVs.

The Army National Guard Soldiers of the 100th Missile Defense Brigade in Colorado and California, and 49th Missile Defense Battalion in Alaska operate the Command, Control and Communication portion of GMD system and are the essential human element of GMD. Missile Defense Element crews from the 100th and Fire Direction Center crews from the 49th man the system 24/7/365. They are responsible for the strategic and tactical level execution of the GMD mission and provide security forces to defend the assets at Fort Greely, Alaska.

The Soldiers of the 100th Missile Defense Brigade are part of a very unique multi-component organization. The brigade headquarters is located in Colorado Springs, Colorado and consists mainly of (full-time) Active Guard and Reserve, Colorado Army National Guardsmen. The unit also includes a small contingent of Active Component (Regular) Army Soldiers. The 100th is tasked with conducting a presidentially-directed national security mission to defend the United States against the threat of ICBM attack.

At Fort Greely, Alaska, the Alaska Army National Guard AGR Solders of the 49th Missile Defense Battalion are charged with the same ballistic missile defense mission as the 100th but have the additional mission essential task for their Military Police to secure the Missile Defense Complex at Fort Greely.

The small contingent of California Army National Guard Soldiers of 100th MDB Detachment 1 at Vandenberg AFB are tasked with performing liaison and asset management of the GBIs located there in support of the brigade and battalion.

In order to perform their federal mission, all 100th MDB National Guard Soldiers operate in a "dual status" allowing them to automatically transition between Title 10 federal Active Duty and Title 32 National Guard status. The Soldiers seamlessly transition between these two statuses depending on the duties they are performing or location. When on-duty at GMD operational sites performing their federal mission they serve in Title 10 and are subject to the Uniform Code of Military Justice. When off-duty or in an administrative status away from GMD operational sites they are in a Title 32 status and are administratively controlled (ADCON) to their respective States' National Guard.

While it may be somewhat normal for regular Army or Army National Guard commanders to command National Guard Soldiers while deployed overseas in a Title 10 status, it is extremely rare for stateside commanders to have the ability to simultaneously command in both status. The 100th Brigade and 49th Battalion commanders are specifically appointed by the president to do so. This situation begs many to question: Why is GMD an Army National Guard mission and not the Regular Army or Air Force?

There is a naturally simple and historic reason. Primarily, defense of the homeland is inherently the mission of the National Guard. The GMD mission is the ultimate defense of the homeland, conducted in support of United States Northern Command (USNORTHCOM), and the 100th has performed this mission without fail 24/7/365 since 2004. On background, there are very sound examples of the Army National Guard performing Air Defense missions dating back to the 1960s with the Nike Air Defense system and mission (Nike, named for the mythical Greek goddess of victory, was the name given to a program which ultimately produced the United States' first successful, widely-deployed, guided anti-aircraft surface-to-air missile system in the early 1950s). At that time with heavy requirements for the Army to support operations during the Vietnam war, manpower was stretched thin and decisions were implemented to man the Nike system with Army National Guard, Air Defense units on a rotational basis. Operational Readiness Evaluations from the era proved that National Guard units could perform long-duration operations for a federal mission just as well as their Active Component counterparts.

Unlike the Air Defense units from the Vietnam era rotationally manning the Nike system, the 100th does not rotate its forces similar to the modern three-stage Army force generation process. The reason for this is simple. There are no other GMD units in the Army. The 100th and 49th do not have any "sister" units to pass the mission off to as they are truly one-of-a-kind. One must also consider the complexity of the training and skill-sets the GMD crews require to be proficient.

"GMD-ers" as they are sometimes called are small in number and undergo an extremely rigorous and lengthy training and certification process. Including Military Occupational Specialty training as an Air Defense Officer or NCO and school wait times, the combined training period for a Soldier to become a gunnery-table certified crewmember can be up to five months. Additional on the job training in subsequent months is also desirable for the Soldier to truly become familiar with day to day operations as well as crisis and combat operations for seamless integration into the crews.

GMD's rigorous training and gunnery-table certification program is overseen by US Army Space and Missile Defense Command/Army Forces Strategic Command. Certification standards for GMD are significantly higher than Army TRADOC standards requiring a 70% minimum academic average for graduation and 80% for Army Air Defense schools. The minimum academic score for GMD written examinations is 90% with the same standard for "hands-on" certification. The reason for these high standards comes largely from the criticality of the GMD mission. When dealing with defense against weapons of mass destruction, there is little room for error.

This long lead time is an additional reason why having GMD manned by Army National Guardsmen is preferred. Unlike their Active Component counterparts who rotate in and out of the unit every 24-36 months, bringing with them fresh ideas and operational experience from the rest of the Air Defense community, Army National Guard Soldiers in the 100th and 49th have the ability to stay for much longer durations. This is not to say that the National Guard Soldiers become stagnant. On the contrary, GMD Soldiers have the ability to move between operational crew positions and brigade/battalion staff or between GMD units in the three states. Although they may choose or be selected for a career broadening assignment within GMD such as operations staff, human resource management, logistics, etc., they generally also maintain their qualification for missile crew duty. This is done through a program known as Alternate Crew Member certification.

The ACM program was specifically designed in order to maintain additional crewmembers to support the temporary loss of regular missile crew Soldiers for periods of leave or school and allow the Soldier to maintain their proficiency on the system while serving on staff. ACMs have an identical gunnery table certification requirement as individual operators and the requirement to pull a minimum amount of shifts to maintain proficiency. Often, ACMs are some of the most experienced operators in the brigade. Some of these Soldiers have continually maintained certification for 10 years or more. It is the ability for these long-serving Army National Guard crewmembers or ACMs to pass along their experience and expertise to the newer generation of operators who may be fully qualified but have less historical experience with real-world system events and behavior.

The GMD system is an extremely complex and reliable system capable of defending the United States against ICBM attack. The Army National Guard and Army Soldiers of the 100th and 49th are truly unique in their ability to successfully man and operate the system. They are just as comfortable talking about squad level field tactics or drill and ceremony as they are about orbital mechanics or radio frequency propagation. Since 1636 the National Guard, originally Colonial Militias, have defended the homeland. GMD Soldiers continue that mission today on the edge of technology against the most destructive weapons on earth. Most Americans don't even know they exist as they stand ready to… GUARD, ENGAGE, and DESTROY.