At Vandenberg Air Force Base, a technician checks on the status of the Orbital Science's Pegasus XL inside Orbital's hanger.

At Vandenberg Air Force Base in California, a technician checks on the status of the Orbital Science’s Pegasus XL inside Orbital’s hanger. The rocket is mated to NASA’s encapsulated Nuclear Spectroscopic Telescope Array, or NuSTAR, spacecraft. A transporter will be used to 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 is expected to be set at the Flight Readiness Review. 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