Final pre-launch preparations are underway for NASA's Nuclear Spectroscopic Telescope Array, or NuSTAR. The mission, which will use X-ray vision to hunt for hidden black holes, is scheduled to launch no earlier than June 13 from Kwajalein Atoll in the Marshall Islands.

The observatory will launch from the belly of Orbital Sciences Corporation's L-1011 "Stargazer" aircraft aboard the company's Pegasus rocket.

Technicians at Vandenberg Air Force Base in central California are busy installing the rocket's fairing, or nose cone, around the observatory. A flight computer software evaluation is also nearing completion and should be finished before the Flight Readiness Review, which is scheduled for June 1.

A successful launch simulation of the Orbital Sciences' Pegasus XL rocket was conducted last week.

The mission plan is for NuSTAR and its rocket to be attached to the Stargazer plane on June 2. The aircraft will depart California on June 5 and arrive at the Kwajalein launch site on June 6.

The launch of NuSTAR from the plane is targeted for 8:30 a.m. PDT (11:30 a.m. EDT) on June 13.