A United Launch Atlas 5 rocket is set to launch the U.S. Air Force’s fourth Advanced Extremely High Frequency communications satellite from Cape Canaveral. This timeline shows the major mission events planned over a three-and-a-half-hour flight to an optimized geostationary transfer orbit.
The 197-foot-tall (60-meter) rocket, propelled by an RD-180 main engine and five solid rocket boosters, is set for liftoff during a two-hour launch window Wednesday that opens at 12:15 a.m. EDT (0415 GMT).
The AEHF 4 mission will be the 79th flight of an Atlas 5 rocket, and the fifth Atlas 5 launch of 2018.
Built by Lockheed Martin, the AEHF 4 satellite joins three previous satellites in the AEHF constellation launched by Atlas 5 rockets in 2010, 2012 and 2013. With four AEHF satellites in orbit, the Air Force’s new generation of secure, nuclear-hardened voice, video and data relay spacecraft will provide global coverage.
An overview of the Atlas 5/AEHF 4 launch sequence and a ground track map illustrating the rocket’s path after liftoff are are posted below.
Packed with nearly 3 tons of rocket fuel, water, oxygen and crew provisions, the Russian Progress MS-12 supply ship and its Soyuz booster arrived at a launch pad Sunday at the Baikonur Cosmodrome in Kazakhstan, moving a step closer to liftoff Wednesday on a fast-track three-hour flight to the International Space Station.
The nine Merlin main engines at the base of a recycled Falcon 9 rocket booster ignited Thursday night for several seconds during a pre-flight test-firing on a Cape Canaveral launch pad, clearing a major hurdle ahead of a scheduled May 31 liftoff with a high-power communications satellite for SES.
NOAA’s JPSS 1 weather satellite is enshrouded inside the nose fairing of a Delta 2 rocket, awaiting liftoff from Vandenberg Air Force Base in California on a seven-year mission to collect data to improve global weather forecasts.