Cape Canaveral - A United Launch Alliance (ULA) Atlas V rocket lifted off from Cape Canaveral Air Force Station on Feb. 9, sending a joint European-U.S. science spacecraft on its way for an unprecedented mission to study the Sun’s polar regions.

Scientists hope the images and data returned from Solar Orbiter’s 10 instruments will help them unravel how the Sun generates its magnetic fields and what drives variations in the 11-year solar cycles. 

Solar Orbiter, a $1.5-billion collaboration between the European Space Agency and NASA, also will monitor the far side of the Sun, which cannot be seen from Earth. Data will be combined with observations from other satellites and ground-based telescopes to create 3D views of the Sun. 

“The Orbiter is really a laboratory,” Daniel Mueller, ESA project scientist, told reporters before launch. “We have a suite of 10 sophisticated instruments that will work together to track the evolution of eruptions on the Sun from the surface, out into space and all the way down to Earth.”

Solar Orbiter is the first mission to try to establish a link between what happens on the Sun and what is observed in the near-Earth environment. “In particular, want to understand how the solar magnetic field works,” Mueller said. 

Scientists currently do not know what drives the solar cycle, nor can they accurately predict how strong future cycles will be. Solar activity drives space weather which can impact GPS and other satellites in Earth orbit, as well as electrical grids and other terrestrial systems. 

The 189-ft tall (58-meter) Atlas V, outfitted with a 4-meter diameter payload fairing, lifted off from Space Launch Complex 41 at 11:03 p.m. EST, the first launch of the year for ULA, a partnership of Lockheed Martin and Boeing. 

Powered by a Russian-made, liquid-oxygen and kerosene-fueled RD-180 engine and a single solid-fuel, strap-on motor, the Atlas arced southeast over the Atlantic Ocean, kicking off a 52-min. flight to send Solar Orbiter on a trajectory to leave Earth orbit. 

After two burns of the Centaur upper-stage, and having reached a velocity of about 27,000 mph, Solar Orbiter was released on a path that will eventually reach inside the orbit of Mercury. 

Getting there will require a single gravitational nudge from Earth and several flybys of Venus to adjust the orbit, bringing the spacecraft closer to the Sun and also out of the plane of the Solar System to observe the star from progressively higher inclinations.

Built by Airbus Space and Defence, Solar Orbiter’s instrument suite is protected with a heat shield designed to withstand temperatures of nearly 1,000 deg. F. Small sliding doors with heat-resistant windows will open to expose the instruments during key points in the mission.

Solar Orbiter will work in conjunction with NASA’s $1.6-billion Parker Solar Probe mission, which was launched in August 2018 to study processes inside the Sun’s atmosphere that generate the high-velocity solar wind and far-reaching radiation and magnetic environments. Parker, with a four-instrument suite, passed just 11.6 million miles from Sun during its fourth close approach in January. 

Scientists are particularly interested in using Solar Orbiter to understand:

*The genesis of solar wind and the forces behind the acceleration of solar wind particles;

*What transpires at the Sun's poles, when the solar magnetic field flips polarity;

*What generates the Sun's magnetic field internally and propagates the force through the Sun's atmosphere and deep into the Solar System;

*How sudden violent solar flares and coronal mass ejections and their energetic particles impact the Earth and the rest of the Solar System.

The first data from the spacecraft is expected in six months. It will take two years for Solar Orbiter to reach its primary science orbit.