Atlas V rocket has narrow window for favorable launch from Cape Canaveral

Update: Watch live as Atlas V lifts off here.

Forecasters are expecting a narrow window of favorable weather for this weekend's launch of a powerful United Launch Alliance Atlas V rocket from Cape Canaveral Air Force Station.

Conditions should be 80 percent "go" for the 7:13 p.m. Saturday liftoff from Launch Complex 41, but a delay to Sunday would likely mean a plummet to 20 percent "go" due to storm activity. The launch window closes at 9:11 p.m.

"In the event of a 24-hour delay, the weather deteriorates significantly with the potential for strong thunderstorms during the count and window," forecasters with the Air Force's 45th Weather Squadron said Thursday. "Very strong, gusty winds are likely in the vicinity of showers and thunderstorms."

Built to its most powerful configuration with five side-strapped solid rocket motors, the Atlas V for Saturday's attempt will boost a multi-payload mission known as Air Force Space Command-11, or AFSPC-11.

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It includes a "forward spacecraft" named Continuous Broadcast Augmenting SATCOM and an "aft spacecraft" labeled ESPA Augmented GEO Laboratory Experiment, or EAGLE. The former is a communications satellite; the latter, an experiment-hosting spacecraft for the Air Force Research Laboratory. Both are expected to separate from the rocket's Centaur upper stage as late as seven hours after liftoff.

For the 321 LAUNCH app, Atlas V is now available in all its configurations for augmented reality-based live launch viewing. Existing users can add Atlas V by downloading version 1.1 of the app through Apple's App Store or Google Play for Android devices.

But the Eastern Range won't get much of a break after Atlas V, as a SpaceX Falcon 9 rocket is slated to take NASA's Transiting Exoplanet Survey Satellite, or TESS, to orbit from Launch Complex 40 at 6:32 p.m. Its mission: find thousands of planets orbiting nearby stars.

SpaceX has not yet confirmed whether the rocket's booster will return for a landing on the Of Course I Still Love You drone ship, though Air Force documents indicate the company will conduct operations at sea after liftoff.

Contact Emre Kelly at aekelly@floridatoday.com or 321-242-3715. Follow him on Twitter and Facebook at @EmreKelly.

Have you tried 321 LAUNCH?

Thanks to cutting-edge augmented reality technology, or the overlaying of digital objects onto the real world made possible by mobile cameras, spaceflight now fits in your pocket. Explore launch pads, rockets and live launches in detail right on your smartphone.

Find the free 321 LAUNCH app in Apple's App Store or in Google Play for Android devices.

Download for Apple devices here.

Download for Android devices here.

Version 1.1 of the app now supports United Launch Alliance's Atlas V rocket in all of its configurations. If you already have the app, be sure to update it to the latest version.

System requirements list:

Apple: iPhone 6S or newer; fifth-generation iPad (2017) or newer. All require iOS 11 and later.

Android's AR capabilities are limited to specific models running 7.0 Nougat and later. See the full list at developers.google.com/ar/discover/.