The Atlas V's single solid rocket booster has been jettisoned. The vehicle is performing as expected. The next major milestone is cutoff of the Atlas booster's main engine.
Solid Rocket Booster Jettisoned

The Atlas V's single solid rocket booster has been jettisoned. The vehicle is performing as expected. The next major milestone is cutoff of the Atlas booster's main engine.
Liftoff! The Atlas V 411 rocket is quickly climbing away from Cape Canaveral Air Force Station in Florida, carrying the Solar Orbiter spacecraft on an international, collaborative mission to view the Sun like never before.
One minute until liftoff of the United Launch Alliance Atlas V rocket and Solar Orbiter spacecraft. Eastern Range is "green," meaning it's "go" for launch.
The countdown has resumed at T-4 minutes and counting. United Launch Alliance and NASA have polled their teams and they're "go" for launch of the Atlas V rocket and Solar Orbiter spacecraft at 11:03 p.m. EST. The spacecraft is on internal power.
Liftoff of the United Launch Alliance Atlas V rocket with the Solar Orbiter spacecraft is on track for 11:03 p.m. EST. Countdown clocks remain in a planned, built-in hold at the T-4 minute mark. The hold will release at 10:59 p.m. — four minutes prior to launch.
Countdown clocks have temporarily paused at the T-4 minute mark. This is a planned, 15-minute hold expected to release at 10:59 p.m. EST. Liftoff of the Solar Orbiter spacecraft aboard a United Launch Alliance Atlas V rocket remains on schedule for 11:03 p.m.
The United Launch Alliance Atlas V rocket carrying the Solar Orbiter spacecraft stands 189 feet tall. It features the 411 configuration, which means 4-meter payload fairing, 1 solid rocket booster and a 1 engine Centaur upper stage.
Good evening from NASA's Kennedy Space Center in Florida. Just a few miles east, a United Launch Alliance Atlas V 411 rocket stands on Space Launch Complex 41 at Cape Canaveral Air Force Station, where it's undergoing final preparations to launch the Solar Orbiter mission at 11:03 p.m. EST. There is a two-hour launch window.
Solar Orbiter builds on the successes of previous missions to study the Sun and its effects on Earth. The mission was developed to study the environment directly surrounding the spacecraft while also observing the Sun, giving scientists a better understanding of how our star can affect the space environment throughout the solar system. The spacecraft also will be the first to provide images of the Sun's poles. The Solar Orbiter mission is planned to last seven years.
A United Launch Alliance Atlas V rocket is poised for liftoff tonight from Space Launch Complex 41 at Florida's Cape Canaveral Air Force Station. On board is the Solar Orbiter spacecraft, an international collaborative mission between the European Space Agency (ESA) and NASA. Countdown clocks across the spaceport are ticking down toward scheduled liftoff at 11:03 p.m. EST. There's a two-hour launch window.