Update for 4:53 pm ET: The United Launch Alliance successfully launched an Atlas V rocket carrying the AEHF-6 military communications satellite for the U.S. Space Force at 4:18 p.m. EDT (2018 GMT). Read our full story here.

A next-generation military communications satellite will launch today (March 26) on the first national security mission for the United States Space Force , and you can watch the liftoff live.

The sixth and final Advanced Extremely High Frequency satellite, or AEHF-6, is scheduled to lift off atop a United Launch Alliance (ULA) Atlas V rocket from Florida's Cape Canaveral Air Force Station Thursday during a two-hour window that opens at 2:57 p.m. EDT (1857 GMT). You can watch the action live here at Space.com courtesy of ULA, or directly via the company .

AEHF satellites circle Earth in geostationary orbit, about 22,200 miles (37,730 kilometers) above the planet.

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The six-satellite system "provides vastly improved global, survivable, protected communications capabilities for strategic command and tactical warfighters operating on ground, sea and air platforms," representatives of aerospace company Lockheed Martin, the prime contractor for AEHF, wrote in a mission description . "The jam-resistant system also serves international partners including Canada, the Netherlands and the United Kingdom."

The first five AEHF craft are already up, having launched in August 2010, May 2012, September 2013, October 2018 and August 2019 , all atop Atlas V rockets. The system has been operational since 2015, and the satellites have a 14-year design lifetime.

A United Launch Alliance Atlas V rocket topped with the AEHF-6 military communications satellite stands at the launch pad ahead of a planned March 26, 2020 liftoff. (Image credit: United Launch Alliance)

AEHF-6 will be the first National Security Space mission for the U.S. Space Force, which was officially established in December 2019.

"In the current dynamic environment, national security is of utmost importance," Gary Wentz, ULA vice president of government and commercial programs, said in a statement . "We are proud to launch the first National Security Space mission for the U.S. Space Force and look forward to delivering the final AEHF asset to support our nation’s national defense and the warfighter community."