What makes Friday's Delta IV launch different from a SpaceX mission?

A United Launch Alliance Delta IV rocket will introduce some smoke and fire to the upcoming St. Patrick's Day weekend, which is set to light up the evening sky on Friday.

The 218-foot-tall Delta IV will take the Air Force's 10th Wideband Global SATCOM spacecraft to orbit from Cape Canaveral Air Force Station's Launch Complex 37 during a window that opens at 6:56 p.m. ET. The window closes at 9:05 p.m.

If it does launch on time, it will mark the first sunset launch of the year for the Space Coast. But how does it differ from a SpaceX launch?

► First, ULA doesn't land its boosters like SpaceX. Instead, it pursues an expendable model (though SpaceX does this for some missions, too) that ditches the rocket's first stage over the ocean. So don't expect a post-launch landing.

► Second, due to Delta IV's four strap-on solid rocket motors, the launch will leave a trail of smoke behind it during liftoff. This differs from SpaceX's Falcon 9, for example, which for the most part doesn't leave a bright white, vertical plume. This is likely to be extra special with sunset occurring 35 minutes after the 6:56 p.m. liftoff.

► Third, though it'll be miles away from spectators, Delta IV is mostly orange – a striking departure from a white-and-black Falcon 9. Some segments of the rocket are white, too, but for the most part is orange. Some of its color should be visible if lighting conditions are right.

This will be the final launch of the WGS program, which produced enhanced communications satellites for American and allied warfighters. And if successful on Friday, this will mark Delta IV's 39th mission.

Also on Friday, meanwhile, Titusville will host the 42nd annual Space Coast Warbird Airshow with a fireworks display that night. Those wanting a good location to view the launch can also head down to Cocoa Beach, which will also host the Beach 'N Boards Fest this weekend. 

Contact Jaramillo at 321-242-3668 or antoniaj@floridatoday.com. Follow her on Twitter at @AntoniaJ_11.

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