languages—Albanian, Arabic, Bosnian, English, Indonesian, Man-
darin, Persian, Russian, Serbian, Spanish, and Ukrainian. VOAalso
puts text, audio, and audio/video on its two Internet sites and has an
aggressive targeted e-mail program to countries where the Internet
site is blocked. See alsoRADIO FREE EUROPE/RADIO LIBERTY;
RADIO MARTI.VORTEX (SYSTEM).Known as the Mercury-Advanced Vortex satel-
lite, it is a classified signals intelligence (SIGINT) satellite capable
of intercepting transmissions from radios, radars, and other electronic
networks. First launched on 10 June 1978 under the code name
CHALET, VORTEX has intercepted telemetry and communications
from target areas. For example, the U.S. government made use of
VORTEX satellites to monitor communications traffic during the nu-
clear accident in the Sovietcity of Chernobyl in April 1986.– W –
WALKER, JOHN ANTHONY, JR. (1937– ).John A. Walker was a
navy employee who in the late 1960s began spying for the Soviet
Union. Specifically, he gave the Soviets information about the navy’s
cryptologicprograms, code machines, and various “keylists” of spe-
cific codes that are used for only a specified period. In the 1970s, he
recruited his friend, Jerry Alfred Whitworth, also a navy employee,
to help in spying. In the early, 1980s, Walker also convinced his son,
Michael Lance Walker, a corpsman stationed on an American aircraft
carrier, to hand classified materials over to him to relay to his Soviet
handlers. The Federal Bureau of Investigation(FBI) arrested the
“Walker Ring” in 1985. According to official assessments, the dam-
age done by Walker and his associates has cost the Department of
Defense(DOD) nearly one billion dollars to replace code machines
and make other changes to secure military hardware.WALK-IN. A“walk-in” is a person who walks into an official facility,
such as an embassy, and volunteers information or his services to an
intelligence service. During the Cold War, Sovietwalk-ins were the
most productive intelligence sources for the West. However, there areWALK-IN• 21505-398 (2) Dictionary.qxd 10/20/05 6:27 AM Page 215