The US space agency launched a satellite late Thursday to unlock the secrets of the Sun's lower atmosphere.

NASA's Interface Region Imaging Spectrograph -- dubbed IRIS -- was launched at 0227 GMT aboard an Orbital Sciences Pegasus XL rocket off the California coast.

"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.

In particular it wants to lear how it gathers energy and heats up as it makes its way through a mysterious region in the sun's lower atmosphere.

This region between the sun's photosphere and corona powers is where most of the sun's ultraviolet emission is generated, which impact the near-Earth space environment and Earth's climate, according to NASA.

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

The mission could help explain what causes the ejection of solar material, including solar wind, but also solar eruptions that can disrupt human technology.

"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.

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