The top secret intelligence-gathering payload for the U.S. government set for launch on top of a Delta 4-Heavy rocket is likely the next in a line of sensitive eavesdropping satellites designed to intercept radio signals and other communications traffic from adversaries around the world.
The 235-foot-tall (71.6-meter) rocket will arc toward the east from Cape Canaveral following a liftoff from pad 37B set for 2:12 a.m. EDT (0612 GMT) Thursday, according to standard pre-launch warning notices released to pilots and mariners to help them steer clear of downrange drop zones under the Delta 4-Heavy’s flight path.
The launch period Thursday extends until 6:25 a.m. EDT (1025 GMT), according to United Launch Alliance, the Delta 4’s builder and operator.
Public information about the Delta 4-Heavy’s easterly trajectory suggests the rocket is heading for a high-altitude circular geosynchronous orbit more than 22,000 miles (nearly 36,000 kilometers) above Earth and closely hugging the equator. Reaching such an orbit requires a rocket to follow one of the most challenging flight profiles in the launch business, with three burns by the Delta’s upper stage to deploy its satellite payload at the targeted altitude.
Four previous Delta 4-Heavy launches in 2009, 2010, 2012 and 2016 ...