Live: Interstellar mapper set for launch

2:23 P.M. BLOGGER UPDATE: NASA has confirmed that the Interstellar Boundary Explorer has successfully separated from its upper stage.

2:11 P.M. BLOGGER UPDATE: The Pegasus XL rocket launched on time at 1:48 p.m., propelling the Interstellar Boundary Explorer on the first leg of a two-year mission to map the edges of the solar system. The spacecraft successfully separated from the Pegasus before the spacecraft's own upper stage ignited. The IBEX flew over the horizon and contact, as expected, was lost. NASA is awaiting confirmation through the Ascension Island ground tracking station that the explorer and the upper stage separated as expected. More to come.

NASA is aiming to launch a mission to map the very edges of the solar system, and you can watch live coverage here in The Flame Trench.

The Interstellar Boundary Explorer mission is scheduled to launch at 1:48 p.m. on a Pegasus XL rocket that will be dropped from the belly of an Orbital Science Corp. L-1011 aircraft flying 39,000 feet above the Pacific Ocean near the Kwajalein Atoll.

Five seconds later, the Pegasus will ignite its first stage, propelling the IBEX spacecraft toward an orbit with a high point of 200,000 miles. Spacecraft sensors will capture high-speed atoms that travel toward Earth from beyond the orbit of Pluto.

Click here to Watch The Launch

Subsequent analyses will help scientists map the region where our solar system ends and the rest of the Milky Way galaxy begins.

"IBEX is really a mission of discovery," said Nathan Schwadron, an associate professor of astronomy at Boston University and co-investigator for the flight. "And what that means for us is we really have never seen the structures that surround and protect the entire solar system."

The region "is critical because it shields out the vast majority of the deadly cosmic rays that would otherwise permeate the space around Earth and other planets," said David McComas, principal investigator from Southwest Research Institute in San Antonio, Texas.

Solar wind data from other satellites indicate the sun's atmosphere -- known as the heliosphere -- is getting weaker. Data from IBEX should enable scientists to determine if increased amounts of galactic cosmic rays are pushing into our solar system.

The $169 million mission is the latest in a series of relatively small NASA science spacecraft that dates back to Explorer 1, the first U.S. manmade satellite, which blasted off 50 years ago from Cape Canaveral Air Force Station.

The launch is being managed by Kennedy Space Center Launch Services Program.