National Security Agency

A

Subocean

Today, a large percentage of international telecommunications travels over fiber optic cables that crisscross the world’s oceans and seas. Packed within these undersea cables are thousands of thin glass fibers about the size of a human hair. When electrical signals are converted to light waves, millions of telephone calls and Internet messages can be transmitted over these cables simultaneously. Using specially modified submarines, such as the USS Jimmy Carter, the NSA is able to tap into many of these cables. However, because it is a very complex technological operation, the agency often tries to short-cut the process by reaching secret agreements with companies that own or maintain the cable landing stations where the cables come ashore. Within the United States, this effort has become very controversial and has led to a number of ongoing lawsuits against telecommunications companies, such as AT&T Inc. and Verizon Communications Inc.

B

Sea

During the 1960s the NSA had a fleet of ships designed specifically for eavesdropping along the coasts of target countries. But after several attacks, including one by Israel against the USS Liberty that resulted in the death of 34 crewmembers and the wounding of nearly 200 others, the NSA gave up its navy. Today, portable equipment, including large self-contained vans, is placed on a wide variety of U.S. Navy ships for short- and long-term missions to sensitive areas.

C

Land

Most of the NSA’s signals-intelligence activities take place on sprawling land-based listening posts both in the United States and in many foreign nations. They are made up of acres of large radome-covered parabolic dishes, some up to 46 m (150 ft) across, as well as a variety of other types of antennae. For reasons of secrecy and to avoid interference from heavy concentrations of electronic signals, like those found in cities, these stations are normally located in remote areas, such as Sugar Grove in West Virginia, and Menwith Hill in Yorkshire, England. These listening posts, also known as intercept stations, collect a wide variety of communications traffic transmitted to Earth from commercial satellites, such as Intelsat, and government satellites from key target countries, including Russia and China. See also Communications Satellite.

Under a program known as Echelon, the United States, the United Kingdom, Canada, Australia, and occasionally New Zealand, share intelligence from their own regions of the world. The signals intelligence agencies in each country are linked by computer, and member nations can ask other members to focus on targets of interest to them.

---

---

D

Air

For many years, specially rigged reconnaissance aircraft such as the U-2 and TR-1 have been used to collect communications and electronic intelligence during flights over or alongside target countries. Target countries may be allies as well as hostile nations. Increasingly, this mission is being conducted with unmanned aerial vehicles such as the small Predator drone and the large Global Hawk unmanned aircraft. They have been used extensively in the conflicts in Afghanistan and Iraq.

E

Space

Because of the enormous amounts of communications transmitted within and between countries through the use of satellites, the NSA makes extensive use of its own eavesdropping satellites both in geostationary equatorial orbit (GEO) over the Earth and also in low Earth orbit. GEO satellites orbit Earth around the equator at a very specific altitude that allows them to complete one orbit in the same amount of time that it takes Earth to rotate once. As a result, these satellites stay above one point on Earth’s equator at all times. The altitude of a GEO satellite is about 35,800 km (about 22,200 mi) above Earth’s surface. A satellite in low Earth orbit (LEO) orbits at an altitude of 2,000 km (1,200 mi) or less. As microwave signals, which travel in a straight line, are transmitted from terrestrial relay tower to relay tower they eventually continue on into deep space. Using highly sophisticated geostationary satellites, the NSA is able to target the communications in which it is interested. Once intercepted by the satellite, the signals are then either retransmitted down to an NSA listening post or passed directly to NSA headquarters at Fort Meade through relay satellites. Sigint satellites in LEO orbit are often used to target ships and submarines at sea. (See also Artificial Satellite.)

Eventually, sometimes after some initial filtering, all the communications collected ends up back at NSA headquarters or one of its major processing stations in Georgia, Texas, or Hawaii. There the intercepts are prioritized, translated, analyzed, and turned into highly secret reports that are forwarded to the government officials responsible for dealing with the topics discussed.

V

History of the National Security Agency

A

Precursors to the NSA