The satellite, known as Advanced Extremely High Frequency 4 (AEHF-4), departed from Space Launch Complex 41 at 12:15 a.m. local time, lighting up the night as the 21-story rocket made its way over the Atlantic Ocean.
According to a Tuesday statement released by the US Air Force Space Command, AEHF-4 "will provide survivable, global, secure, protected and jam-resistant communications for high-priority military ground, sea and air assets."
The Lockheed Martin-built satellite was deployed some three hours after liftoff into an orbit about 22,300 miles above Earth. Designed to replace the US military's Milstar system, a constellation of military satellites operated by the US Air Force, AEHF-4 is preceded by three satellites and will be joined an additional two to complete the project.
"The mission of AEHF is to provide survivable protected communications for the military's high-priority assets on the ground, at sea and in the air," said Maj. Matthew Getts, of the Air Force's Space and Missile Center in Los Angeles, California, after the launch, according to Space.com.
"It also enables the president of the United States and combatant commanders to control their tactical and strategic forces through all levels of war and all phases of conflict."
The fifth satellite, AEHF-5, is scheduled for launch on July 2019. The previous three AEHF spacecrafts were launched atop Atlas 5 rockets in 2010, 2012 and 2013, according to website Space Flight Now.
It's unclear when the sixth satellite will be sent into orbit.
Ahead of the Wednesday launch, Mike Cacheiro, Lockheed Martin's vice president of protected communications and AEHF program manager, told reporters in a conference call that "on a really bad day, you really want to have this system in place."
"This is the nation's only strategic and tactical protected communications satellite network," local outlet Florida Today reported Cacheiro saying.
"It's also the only system that survives through a near nuclear burst and can provide communications through scintillated environments that other communications systems could not."
The next United Launch Alliance mission will see the US National Reconnaissance Office's NROL-71 spy satellite launched from the California's Vandenberg Air Force Base later this year.