How NORAD Works

By: Ed Grabianowski  | 
An F-16 flies a NORAD mission over New York City in 2003. See more pictures of military jets.
U.S. Air Force/AFP/Getty Images

NORAD, the North American Aerospace Defense Command, is a military operation run jointly by the United States and Canada. Originally headquartered in a massive complex built within a hollowed-out mountain near Colorado Springs, NORAD's goal is to monitor all possible approaches to the United States via air and space for potential attacks. Created at the height of Cold War paranoia, NORAD is a technological wonder that has been forced to adapt continually to new threats.

In this article, we'll take a brief look at the history of NORAD, the technology behind its operations and where the command stands today.


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­Deter, Detect, Defend

To understand NORAD, it's important to understand the Cold War fears that spawned it. Consider this quote, written in 1967:

Compare [the Japanese attack on Pearl Harbor] with the threat that the people of North America face today: Supersonic and subsonic jet bombers, several hundred in number, capable of reaching any target on the continent; intercontinental ballistic missiles that can travel from deep within the Eurasian land mass at 15,000 mph … submarine-launched ballistic missiles that could strike 40 of the continent's largest cities less than five minutes after launch … Soviet Cosmonauts are harbingers of future danger [source: ­Talmadge].

NORAD's motto is "Deter, Detect, Defend." Deterrence was accomplished simply through the fact of NORAD's existence. "Potential enemies know that they would suffer disastrous consequences at once if they should be so foolish as to launch an attack against the United States or Canada. Full knowledge of these facts is considered the greatest safeguard and deterrent against sneak attack," reads the introduction of a NORAD guidebook published in 1970 [source: ­Hough]. In many ways, the creation of NORAD was an act of Cold War propaganda. This is not to suggest that NORAD wasn't capable of doing the things the United States claimed it could do, just that the claims were at least as important as the technology itself.

Detection was accomplished with an ever-growing series of radar installations stretching across Canada. If you look at a globe from directly above, you can see that the shortest path between the United States and Russia is through the Arctic, placing Canada directly between the two Cold-Warring nations. NORAD's "radar fence" was meant to act as a first line of defense, giving as much advance warning as possible when attack planes or missiles were launched toward the United States or Canada. This would provide time to react (with retaliatory missiles) and possibly affect some form of evacuation or allow civilians to reach bomb shelters.

Special squadrons of Air Force fighters and bombers (Strategic Air Command, or SAC squadrons) were set up to perform the defense aspect of NORAD's motto. Able to scramble and take to the air on a moment's notice, these planes could be used to intercept and destroy incoming enemy aircraft. Incoming missiles couldn't be dealt with in any practical way, so bombers would be sent to fire missiles at Russia, ensuring the mutual destruction of both nations.



NORAD Technology

Cheyenne Mountain, site of the NORAD control center
Photo courtesy North American Air Defense Command, Public Information Division

The technology NORAD used to accomplish its mission was made of three main parts:

  • Detection: mainly using numerous radar installations
  • Command and control: using state-of the-art computer and communications systems housed in Cheyenne Mountain
  • Response: using the Air Force's fighters, bombers and missiles

­The first set of NORAD radar stations, the Pinetree Line, used pulse radar, which had trouble detecting planes close to the ground. The line, built in 1954, ran roughly along the U.S./Canadian border in the west, then cut across eastern Canada. This was too close to the potential targets of Soviet attacks to provide much advance warning. Pinetree was quickly supplanted by the Mid-Canada Line (MCL), which was positioned farther north. The MCL used Doppler radar, a more advanced technology that offered increased efficiency and low-altitude detection. The construction and early operations of these two systems actually predated the formation of NORAD by several months.


The Distant Early Warning (DEW) line of radar was built at almost the same time as the MCL. It stretched across Alaska, northern Canada and Greenland several hundred miles north of the Arctic Circle. Completed in 1958, the DEW line, like the Pinetree Line and MCL, was designed to detect Russian jet bombers. However, the transition to Intercontinental Ballistic Missiles (ICBMs) made these systems obsolete almost immediately [source: Talmadge]. MCL and Pinetree were no longer in use by the mid-1960s, while DEW stations were gradually shut down or converted to other uses, although some stations remained operational into the 1990s.

The Ballistic Missile Early Warning System (BMEWS) was NORAD's answer to ICBMs. Three massive radar installations in Alaska, Greenland and Britain make up the BMEWS, which went into operation in 1960 [source:Talmadge]. The BMEWS radar operated at such long range that its mission was expanded to include monitoring of orbital satellites. All three BMEWS stations are still in operation (following upgrades in recent decades), though the Alaskan station was converted into a PAVE PAWS installation. PAVE PAWS is the most modern NORAD air and space tracking system, first implemented in the 1980s.

Interpreting and combining the information from all these radar systems requires the use of sophisticated computer systems (at any given moment, been repeatedly upgraded over the decades). Each radar station is connected to NORAD command and control by redundant communications systems, using hardwired connections and satellites as well as microwave communications.

Today, NORAD is able to track virtually every inch of North American air space and can detect missile launches almost anywhere in the world, using satellites to spot heat signatures and exhaust plumes. In addition, NORAD tracks all man-made objects in space. All of this information is cross-referenced with civilian and military air traffic control. As a result, NORAD can quickly detect an unauthorized aircraft. Many of these turn out to be drug smugglers -- about 100 are caught each year with NORAD's help [source: Above Top Secret].


Cheyenne Mountain

A worker inspects one of the 1,000-pound springs under the NORAD complex in Cheyenne Mountain, Colo.
Photo courtesy North American Air Defense Command, Public Information Division

The most famous part of NORAD is probably the NORAD headquarters and control center. The United States wanted a control center that could be temporarily self-sufficient and withstand a nuclear attack, so it hollowed out a granite mountain in Colorado to house it. The Cheyenne Mountain complex is enclosed by 25-ton steel blast gates and hundreds of feet of solid granite. The inner area is a series of large chambers covering more than four and a half acres [source: Talmadge]. Within the chambers are buildings, built as freestanding structures within the mountain. Each building rests on immense coiled steel springs for isolation from the seismic shock of a nuclear blast (they work against earthquakes, too). Each of the 900 springs weighs 1,000 pounds [source: Hough]. Extensive ventilation systems provide fresh air, while food stores and natural water springs can provide sustenance for up to a few weeks. The center does have a generator, but it draws power primarily from the local electric grid.

Construction of the complex began in 1961 and cost $35.5 million for the first phase. It took three years and more than a million pounds of explosives just to hollow out the mountain [source: ­Hough]. Ultimately, Cheyenne Mountain cost hundreds of millions of dollars to maintain and upgrade. As of 1994, annual operating costs for the facility were $152 million [source: Above Top Secret].


More than 1,800 people once worked within the mountain, but in 2006 NORAD's operations were shifted to Peterson Air Force Base in Colorado Springs. A skeleton crew continues to maintain the Cheyenne Mountain complex in a "warm standby" state, ready for use as a backup whenever it may be needed.

Until recently, the Canadian NORAD headquarters was also centered in an underground complex. It was located in North Bay, Ontario, and housed most of the computer and communications systems. The Canadian NORAD command also uses a military base in Winnipeg, Manitoba, which serves as the administrative headquarters [source: National Defence of Canada].

On the next page we'll learn about what happens if NORAD spots a missile coming toward the United States.


Alarm Levels and Joint Operations

The NORAD command center in the late 1960s/early 1970s
Photo courtesy North American Air Defense Command, Public Information Division

NORAD's highest level of alert during the Cold War was Alarm Level 1. Fortunately, it was never activated, but a Level 1 contact would have played out like this:

The Ballistic Missile Early Warning System (BMEWS) detects something flying within its radar range. The computer systems check and don't recognize the object. It appears as a colored light on an electronic map of North America, and Alarm Level 3 is activated. The computers begin making predictions -- if the object is a missile, where might it be aimed, and how long will it take to get there?


Once the BMEWS starts tracking the object, it will be able to tell where it's heading. If it's moving toward or into North America, NORAD moves to Alarm Level 2. At this level, a series of checks are run to make sure the object isn't a bad signal or something harmless. If nothing checks out, NORAD moves to Alarm Level 1.

Strategic Air Command (SAC) squadrons have already been notified and are scrambling -- now they can be released into the air. Missile launch sites are on alert and preparing to launch. Meanwhile, computers continue tracking and refining the missiles' estimated impact sites. Once everything has been fully confirmed, all possible mistakes are ruled out and NORAD commanders know for certain that the United States is under attack, they then reach for the Presidential hotline. This special phone connects directly to the President without delay. Only with his authorization can military elements be fully activated to attack and launch their missiles.

Joint Operations

NORAD is a rarity -- an ongoing joint defensive military operation between two countries. The U.S. and Canada realized in the 1950s that any Russian threat posed to one was also going to be faced by the other. In the interest of working together to detect and stop such threats, the two nations signed an agreement to form NORAD on May 12, 1958 [source: National Defence of Canada]. It was originally known as North American Air Defense Command, but "Air" was changed to "Aerospace" to reflect the expanded duties brought on by satellites and other space-born threats.

NORAD's commander is appointed by (and answers to) the U.S. President and the Canadian Prime Minister. An American Air Force general is usually chosen to be NORAD commander, with a Canadian deputy commander. The NORAD agreement has been steadily renewed over the years, though the two countries have disagreed on the funding of facility construction and maintenance. Most of NORAD's functions are accomplished by the two nations' air forces, but because it is a binational agency, it is not technically a part of either air force.

In the United States, the 21st Space Wing of the U.S. Air Force provides missile warning and space control functions to NORAD. And various air wings throughout the United States provide the actual air-combat presence of NORAD. The Royal Canadian Air Force operates Canadian NORAD bases.

On the next page we'll learn about how NORAD works today and how it has changed with the end of the Cold War and the new threat of terrorism.




One of the 25-ton blast doors that protect the NORAD Cheyenne Mountain complex
Robert Nickelsberg/AFP/Getty Images

NORAD has changed in many ways since the end of the Cold War. While tracking drug smugglers helped keep it relevant in the 1990s, the terrorist attacks of 2001 drastically changed NORAD. Since its inception, NORAD's very nature has been to monitor the North American airspace for threats coming from other nations. An airborne attack from within U.S. borders was not expected. In fact, when Air Force fighters were first sent into the air on Sept. 11, 2001, some of them followed predetermined mission plans that sent them out to sea to intercept incoming attackers [source: Colorado Springs Gazette].

Following the attacks, NORAD turned its watchful eyes inward, intently scanning U.S. skies for threats. When a civilian plane crashed into a New York City apartment building in October 2006, NORAD sent Air Force fighters into the skies above New York and other major North American cities within minutes [source: Colorado Springs Gazette].


In 2005, NORAD adopted a new system using low-intensity lasers to warn commercial airline pilots when they've entered restricted airspace above Washington, D.C., near military installations and other sensitive areas. The system is more effective and less expensive than the previous method of sending fighter jets to intercept the plane [source: Airline Industry Information]. NORAD's systems and communications have been better integrated with the Federal Aviation Administration's oversight of civilian air traffic. This includes FAA officials working directly with NORAD [source: Calgary Herald].

Canada has also recently moved its NORAD operations -- headquarters are now in an aboveground building near the North Bay bunker .

What does the future hold for NORAD? The United States and Canada will probably always need a way to monitor the skies for potential threats, and those threats will continue to evolve. The methods used to accomplish NORAD's mission will change with technology, always shifting to meet the needs of national security, just like they have since the 1950s.

For more information on NORAD and related topics, check out the links on the following page.


Frequently Answered Questions

What does NORAD stand for?
The North American Aerospace Defense Command.

Lots More Information

Related HowStuffWorks Articles

More Great Links

  • Airline Industry Information. “NORAD to use laser beams to warn pilots.” April 12, 2005.
  • Boeing. “Ground-based Midcourse Defense (GMD) Background.”
  • Canadian Department of National Defense. “Backgrounder: NORAD.”
  • “Cheyenne Mountain and the NORAD Complex.” Above Top Secret.
  • “Yankees pitcher killed in crash of small plane in Manhattan.” Oct. 12, 2006.
  • Hough, Henry W. NORAD Command Post: The City Inside of Cheyenne Mountain. Green Mountain Press (1970). 978-0877680062.
  • NORAD. “About NORAD.”
  • Slobodian, Linda. “Norad on Heightened Alert: Role of air defence agency rapidly transformed in wake of Sept. 11 terrorist attacks.” The Calgary Herald, Oct. 13, 2001.
  • Stockman, Tom. “Memoir: NORAD False Alarm of Soviet Missile Attack, November 9 1979.”
  • ­Talmadge, Marian and Gilmore, Iris. NORAD: The North American Air Defense Command. Dodd, Mead (1967).
  • Zubeck, Pam. “Closing NORAD may cost $12B.” The Colorado Springs Gazette, June 15, 2007.
  • Zubeck, Pam. “Minutes after crash, NORAD was there.” The Colorado Springs Gazette, Oct. 12, 2006.