June 12, 2013: A day before the L-1011 carrier aircraft will depart Vandenberg Air Force Base to ferry the Orbital Sciences air-launched Pegasus rocket and its NASA X-ray space telescope to the Kwajalein Atoll in the Pacific, reporters got a tour of the jet and rocket at the "hot pad" staging area adjacent to the runway. This will be the 41st flight of the winged Pegasus.

The carrier jet has been launching Pegasus rockets for 18 years.

The 51,000-pound rocket is secured to the aircraft by five hooks.

The L-1011 will carry Pegasus to 39,000 feet at Mach 0.8 for its launch.

Pilot Bill Weaver (left) and co-pilot Ebb Harris (right) in the cockpit.

Weaver shows the arm switch and release button used to launch the Pegasus.

Launch Panel Operators in the first class section of aircraft monitor rocket systems.

Pegasus is readied for its 4,700-mile ferryflight to the equatorial launch site.

Orbital's L-1011 aircraft took off from Vandenberg Air Force Base at 0131 UTC on Jun 28, 2013 and flew out to the standard drop location at 123.0W 36.0N over the Pacific. The Pegasus XL vehicle was dropped at 0227:46 UTC according to NASA commentator G. Diller; the first stage ignited 5 seconds later.
The third stage ignited 8min 58s after drop to place IRIS in orbit; the spacecraft separated 4 min later in a 616 x 663 km x 97.9 deg orbit.