
Orbital Science’s Pegasus XL rocket in flight.
IRIS is a NASA Small Explorer (SMEX) mission to measure the Sun’s flow of energy through the dynamic region in the solar corona and heliosphere to help scientists better understand the effects of solar energy release processes on Earth. The planned 2012 launch will be the rocket’s 45th mission since its initial flight in 1990 and the second Pegasus launch scheduled for that year, following the launch of the Orbital-built NuSTAR scientific satellite in February 2012.

Orbital Science’s Taurus XL rocket on launch pad.


