Delta IV launch Saturday promises 'Super' show

Update, 11 a.m. Saturday:

The weather forecast is nearly perfect for this evening's planned 7:44 p.m. launch of a Delta IV rocket and military communications satellite from Cape Canaveral Air Force Station.

There's less than a 10 percent chance of conditions that would violate launch rules during a 75-minute window at Launch Complex 37, according to the Air Force's 45th Weather Squadron.

The complex's Mobile Service Tower soon will roll back to reveal the 217-foot rocket and payload on their pad. Preparations to fuel the two-stage rocket with liquid hydrogen and liquid oxygen will begin several hours before launch.

Earlier story:

Space Coast viewers could be in for a treat Saturday with a powerful Delta IV rocket's planned twilight blastoff from Cape Canaveral Air Force Station.

The 217-foot United Launch Alliance rocket is targeting liftoff at 7:44 p.m., about 10 minutes after sunset, and will receive an extra boost from four solid rocket motors attached to the first stage.

“It’s a good time for a launch,” said Brig. Gen. Wayne Monteith, commander of the Air Force’s 45th Space Wing. “That dusk time is beautiful, and then to have the four solids on, it’s a show.”

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If the launch of a heavy military communications satellite occurs on time, the rocket will bolt from Launch Complex 37 with more than 1.8 million pounds of thrust.

As it climbs over the Atlantic Ocean, the trail of exhaust from the solid boosters will catch the fading sunlight and turn bright white as it streaks through a darkening sky, perhaps through colorful clouds.

“With four solids, if you’re there in the local area, it’s going to be a pretty amazing experience with the sound and the vibration and the acoustics from the vehicle lifting off,” said Laura Maginnis, ULA’s vice president for government satellite launches. “For those viewing at the launch site, it will be a pretty powerful sight and pretty quick off the launch pad with those solid motors.”

The launch window extends to 8:59 p.m., so a twilight launch could turn into a night launch if any issues crop up during the countdown.

Weather doesn’t figure to be a factor, with the Air Force’s 45th Weather Squadron predicting a 90 percent chance of favorable conditions.

A backup launch opportunity is available Sunday evening, if necessary.

Flying on top of the rocket is the Air Force’s ninth Wideband Global Satcom satellite, or WGS-9, the latest addition to a constellation forming the Defense Department’s highest capacity space-based communications network.

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The $424 million satellite, built by Boeing, was bought by five international partners who gained access to the network: Canada, Denmark, Luxembourg, the Netherlands and New Zealand.

The mission was delayed from March 8 to fix an engine issue found during pre-launch inspections.

Before the delay, the Air Force was promoting the flight as the “Super Bowl of launches,” a showcase event helping to kick off yearlong celebrations of the service’s 70th anniversary.

The Delta IV's nose cone is painted with the Air Force’s 70th anniversary "Breaking Barriers" logo, along with mission artwork featuring the partner countries’ flags.

Hundreds of guests including international partners and the head of Air Force Space Command had been expected to attend the launch, which coincided with an Air Force conference in Orlando. The delay scrapped those plans.

Fewer VIPs may be in attendance, but the Space Coast can still look forward to an eye-catching launch.

Contact Dean at 321-242-3668 orjdean@floridatoday.com.And follow on Twitter at@flatoday_jdeanand on Facebook atfacebook.com/jamesdeanspace.

Launch Saturday

Rocket: United Launch Alliance Delta IV (5,4)

Mission: Air Force's ninth Wideband Global Satcom communications satellite

Launch Time: 7:44 p.m.

Launch Window: to 8:59 p.m.

Launch Complex: 37 at Cape Canaveral Air Force Station

Weather: 90 percent "go"

Join floridatoday.com at 6:30 p.m. for countdown chat and updates, including streaming of ULA's launch broadcast starting 20 minutes before liftoff.