John W. "Jack" King, whose calm, assured reporting of the countdown of the Apollo 11 moon mission launch earned him the sobriquet "Voice of NASA," has died following a long illness.

King, who was 84, died of congestive heart failure in Cocoa Beach, Florida, his daughter Beth King Post announced.

Originally from Boston, King came to Florida in 1958 as an Associated Press reporter to cover space launches from Cape Canaveral, becoming bureau chief for the AP Cape Canaveral Bureau.

In 1960, he became the head of NASA's public information office during the Mercury program and worked in that capacity through the Gemini and then Apollo programs before leaving NASA in 1975.

During the Apollo launch in 1969, his was the voice delivering countdown commentary as the launch approached, giving descriptions of critical events of the countdown as the public hung on every word.

King was instrumental in opening America's civilian space program to the public and the media, NASA said on a website honoring King.

"Jack helped establish the original systems to ensure the news media received timely and accurate information about both the early human flight programs and the unmanned missions," said Hugh Harris, retired director of NASA Public Affairs at Kennedy Space Center.

Many early launches at Cape Canaveral were classified as military missions, so King had to convince NASA of the need for a new way of working with the media and the public as the Mercury program began.

"The biggest PR job I had to do was with our own people in order to get information that I could pass out to the news media," King said during an interview in 2002. "These were the early days when things were just starting out."

In the 12 years he served as manager of press operations, King was in the public mind as "the voice of launch control" for almost every manned mission from Gemini 4 through Apollo 15.

It is estimated that more than a billion people listened to his commentary during the Apollo 11 launch.

After leaving government service in 1977 and spending time in public affairs for several commercial enterprises, King returned to Florida in 1997 to serve as head of news media relations for United Space Alliance, NASA's main contractor for day-to-day operation of the Space Shuttle program.

He retired for good in 2010.

"He was one of the pioneers as far as public affairs was concerned," Harris said. "He developed many of the ways (NASA works) with the media (today and) he was very close to many of the reporters. He was one of a kind."