An Orbital technician consults documentation to ensure all steps in the transfer of an Pegasus XL rocket.

In Orbital Science’s hangar at Vandenberg Air Force Base in California, an Orbital technician consults documentation to ensure that all steps in the transfer of an Pegasus XL rocket onto the transporter are properly executed. The rocket is mated to NASA's Nuclear Spectroscopic Telescope Array, or NuSTAR, telescope, encapsulated in the Pegasus payload fairing. Cool, dry air is being pumped into the fairing through a purge line to maintain the proper environment for the spacecraft in the confined space.

The transporter will move them to the runway ramp where they will be attached to the underside of Orbital’s L-1011 carrier aircraft. The aircraft will fly the pair from Vandenberg to the Ronald Reagan Ballistic Missile Defense Test Site on the Pacific Ocean’s Kwajalein Atoll for launch. A revised launch date will be set at the Flight Readiness Review, planned for later this week. The high-energy X-ray telescope will conduct a census of black holes, map radioactive material in young supernovae remnants, and study the origins of cosmic rays and the extreme physics around collapsed stars. For more information, visit http://www.nasa.gov/nustar. Photo credit: NASA/Randy Beaudoin, VAFB