NASA is preparing to launch a spacecraft tonight that scientists hope will answer fundamental questions on how the sun creates such intense energy.
The IRIS (Interface Region Imaging Spectrograph) spacecraft is set to launch at 10:27 p.m. ET from Vandenberg Air Force Base in California. The 7-foot-long spacecraft will fly in Earth's orbit and use its ultraviolet telescope to study the interface region of the sun, which lies between the star's surface and the million degree outer atmosphere called the corona, NASA said.
Watch the launch live tonight on NASA TV Coverage begins at 9 p.m. ET.
The project is aimed at helping scientists understand how energy moves from the sun's surface to the corona, going from 6,000 degrees to millions of degrees.
"We're always looking for the answers to why, and everything starts at the root with the sun," said Jim Hall, NASA's mission manager for IRIS. "It's going to look in closely and it's going to look at that specific region to see how the changes in matter and energy occur in this region. It's going to collectively bring us a more complete view of the sun."
The space agency also reported that it's important to understand how the sun's ultraviolet emissions are generated since they affect the near-Earth space environment, as well as Earth's climate. NASA's spacecraft designers also need more information on solar activity, such as coronal mass ejections and solar flares, to help them figure out ways to protect instruments and electronics.
The IRIS spacecraft, attached to an Orbital Sciences Pegasus XL rocket, will leave Earth on board a modified L-1011 airliner. Once the airliner reaches about 39,000 feet, it will release its cargo, and five seconds into its fall, Pegasus will begin its in-air launch and carry IRIS the rest of the way into orbit.
Pegasus is well known as the only winged launcher in NASA's inventory. It was designed to carry smaller spacecraft into space.
Once IRIS is in orbit, it will unfold its solar panels, which will provide it with power, and it will flip open its telescope.
NASA said scientists expect to quickly begin to see intriguing data coming from the spacecraft.
"I think the biggest surprise will come once the mission is launched and it starts to observe the sun," said Adrian Daw, IRIS's deputy project scientist. "We know to some extent what we hope to learn, what specific science questions we are going to answer, but there's always that element of surprise."
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