NASA has launched a spacecraft to unlock the secrets of the Sun`s lower atmosphere.

The IRIS telescope, short for Interface Region Imaging Spectrograph, was launched aboard an Orbital Sciences Pegasus XL rocket off the California coast in the United States on Thursday.

"We`ve got a very happy spacecraft on orbit and a thrilled launch team on the ground," NASA Launch Manager, Tim Dunn, said in a post to the agency`s blog shortly after launch.

The goal of the $182 million mission, to last at least two years, is to observe the movement of solar material.

IRIS will examine why the surface of the sun is much cooler than the massive solar flares it releases.

The surface of the sun reaches five thousand degrees centigrade, but massive solar flares reach up to three million degrees.

In particular, IRIS wants to learn how the Sun gathers energy and heats up as it makes its way through a mysterious region in its lower atmosphere.

Solar flares impact the earth`s weather and affect telecommunication signals, according to NASA. The mission could help explain what causes the ejection of solar material, including solar wind.

"IRIS will help scientists understand the mysterious and energetic interface between the surface and corona of the sun," said John Grunsfeld, NASA`s associate administrator for science.

IRIS will take high resolution photos of this mysterious region at intervals of several seconds.

Engineers will test IRIS for about a month before activating it to start its observations.