NASA launches spacecraft to probe mysteries of the sun's atmosphere

VANDENBERG AFB, Calif., June 28 (UPI) -- NASA says a compact solar observatory was successfully launched into a polar Earth orbit, where it will study the sun's atmosphere.

The Interface Region Imaging Spectrograph, or IRIS, spacecraft will gather data to determine what heats the sun's outer atmosphere to extreme temperatures and how that affects space weather experienced on Earth, NASA said in a release Friday.

IRIS will observe how solar material moves, gathers energy and heats up as it travels through a little-understood region in the sun's lower atmosphere, between its photosphere and corona, which powers its million-degree atmosphere and drives the solar wind, NASA said.

The solar wind -- atomic particles blasted away from the sun -- solar flares and explosive eruptions known as coronal mass ejections can sometimes disrupt power grids, satellite operations and communications on Earth.

"What we want to discover is what the basic physical processes are that transfer energy and material from the surface of the sun to the outer atmosphere of the sun, the corona," Alan Title, IRIS principal investigator at Lockheed Martin's Advanced Technology Center, said before the launch. "The visible surface (is) the place where virtually all of the light that leaves the sun leaves from. Immediately above that, the temperature rises to the million-degree corona. How that happens is a mystery. What are the processes that occur there?"

NASA engineers said they would spend two months checking out the spacecraft's systems and calibrating its instruments before beginning a program of science observations of the sun.