NASA Launches Sun-Watching Telescope to Probe Solar Secrets

  

NASA's newest solar observatory launched into space late Thursday (June 27), beginning a two-year quest to probe some of the sun's biggest mysteries.
An Orbital Sciences Corp. Pegasus XL rocket and the new solar telescope — called the Interface Region Imaging Spectrograph satellite, or IRIS — left California's Vandenberg Air Force Base underneath a specially modified aircraft at 9:30 p.m. EDT Thursday (6:30 p.m. local time; 0130 GMT Friday).
Nearly one hour later, at 10:27 p.m. EDT (7:27 p.m. local time), the plane dropped its payload 39,000 feet (11,900 meters) above the Pacific Ocean, about 100 miles (160 kilometers) northwest of Vandenberg. After a five-second freefall, the Pegasus rocket roared to life and carried the sun-watching IRIS into Earth orbit. [NASA's IRIS Solar Observatory Mission in Pictures]

"We're thrilled. We're very excited," NASA launch director Tim Dunn said just after the successful blastoff. "We've gotten good data back. The solar arrays did begin to deploy and everything is proceeding right on track."
Scientists hope IRIS' observations help them better understand how energy and material move around the sun. They want to know, for example, why the outer atmosphere of the sun is more than 1,000 times hotter than the star's surface

Solar mysteries
IRIS is part of NASA's Small Explorer program, which caps the cost of a space mission at $120 million. Like its budget, the spacecraft is small, weighing just 400 pounds (181 kilograms) and measuring 7 by 12 feet (2.1 by 3.7 m) with its power-generating solar panels deployed.

After a 60-day checkout period on orbit, IRIS will begin its science campaign. The probe will stare at a mysterious sliver of the sun between the solar surface and its outer atmosphere, or corona.
Researchers hope a better understanding of this interface region, which is just 3,000 to 6,000 miles (4,800 to 9,600 kilometers) wide, helps explain why temperatures jump from 10,000 degrees Fahrenheit (5,500 degrees Celsius) at the sun's surface to 1.8 million degrees F (1 million degrees C) or so in the corona.