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Atlas V to Launch AEHF-4

Rocket: Atlas V 551
Mission: AEHF-4
Launch Date: Wednesday, Oct. 17, 2018
Launch Time: 12:15-2:15 a.m. EDT
Launch Broadcast: Tune in Oct. 16 at 11:55 p.m. EDT
Launch Location: Space Launch Complex 41, Cape Canaveral Air Force Station, Florida

Mission Information: United Launch Alliance will use an Atlas V 551 rocket to launch the fourth communications satellite in the Advanced Extremely High Frequency (AEHF) series for the U.S. Air Force.

AEHF satellites provide highly-secure, jam-proof connectivity between U.S. national leadership and deployed military forces. Atlas V rockets successfully launched the first three AEHF satellites in 2010, 2012 and 2013 as the new constellation was formed in geosynchronous orbit 22,300 miles above Earth.

Launch Notes: This will be 131st mission for United Launch Alliance and our 50th launch for the Air Force. It is the 79th for an Atlas V rocket and the 9th in the 551 configuration.

Launch Updates: To keep up to speed with updates to the launch countdown, dial the ULA launch hotline at 1-877-852-4321 or join the conversation at, and; hashtag #AtlasV


Go Atlas! Go Centaur! Go AEHF-4!


The Atlas V 551

United Launch Alliance’s Atlas V rocket is a workhorse for the U.S. military, intelligence community and scientific researchers, having flown 78 successful missions since debuting in August 2002. Developed as a modular vehicle, each Atlas V is tailored to the needs of its passenger by adding as many as five side-mounted solid rocket boosters for increased lift performance and a variety of available payload fairings in various diameters and lengths to protect satellites during atmospheric ascent. The high-energy Centaur upper stage, which has been used to send spacecraft to every planet in our solar system, is incorporated into Atlas V to deliver the payloads to their intended destinations.


  • Height: 197 feet
  • Weight: 1.3 million pounds
  • Thrust: 2.6 million pounds

For the AEHF-4 mission, the Atlas V 551 variant will be used. The rocket features a kerosene-fueled common core booster, five strap-on solid rocket motors, the hydrogen-fueled Centaur upper stage and a five-meter-diameter payload fairing. This configuration launched the New Horizons spacecraft to Pluto and the Juno probe to Jupiter, plus the Navy’s five MUOS satellites and the Air Force’s AFSPC-11 mission.



United Launch Alliance (ULA) will use an Atlas V 551 rocket to launch the fourth Advanced Extremely High Frequency communications satellite for the U.S. Air Force from Space Launch Complex-41 at Cape Canaveral Air Force Station, Florida.


Space Launch Complex 41

Space Launch Complex 41, the East Coast home of the Atlas V rocket at Cape Canaveral Air Force Station in Florida, employs a “clean pad” concept of operations to ready launch vehicles and payloads for ascent into space. The rocket elements are assembled atop a Mobile Launch Platform inside the Vertical Integration Facility located adjacent to the launch pad. The platform and fully stacked Atlas V then travels by rail approximately 1,800 feet northward from the VIF to the pad for the final countdown, fueling and liftoff.

Complex 41 was constructed by the U.S. Air Force in the 1960s for the Titan rocket program. The site was rejuvenated in support of the Atlas V starting in the late 1990s. AEHF-4 will be the 64th Atlas V launch from this pad and the 91st overall since 1965.