IRIS is a NASA Small Explorer Mission designed to observe how solar material moves, gathers energy and heats up as it travels through a little-understood region in the sun's lower atmosphere. This interface region between the sun's photosphere and corona powers its dynamic million-degree atmosphere and drives the solar wind.
IRIS will be launched aboard a Pegasus XL rocket that is dropped from a L-1011 aircraft in mid-flight. The drop of the air-launched Pegasus will occur over the Pacific Ocean at an altitude of 39,000 feet, about 100 miles northwest of Vandenberg Air Force Base, Calif. The L-1011 will takeoff from Vandenberg.
Because of a significant power outage at Vandenberg earlier this week, certain Western Range facilities were not be ready to support the original Wednesday launch date. A Launch Readiness Review meeting for the IRIS mission on Wednesday concluded that all Pegasus and satellite systems are ready for flight.
“The Western Range has been successful in restoring power to the range systems,” NASA said in a IRIS Status Update. “The range does not anticipate any issues in finishing the activation and at this time, the work is going smoothly.”
The launch team will begin preparing the L-1011 for departure at 5:30 p.m. on Thursday. Departure is planned to occur at 9:27 p.m. and the drop of the Pegasus XL is targeted for 10:27 p.m.
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