VANDENBERG AIR FORCE BASE, Calif. -- Following the first Interface Verification Test, a technician removes cables providing the electrical connections between the Interface Region Imaging Spectrograph, or IRIS, spacecraft and the Orbital Sciences Corp. Pegasus XL launch vehicle. Completion of the test paves the way for the standalone IRIS mission simulations. IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the suns corona using spectrometry and imaging. IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere.