Video: X-37B payload mated to Atlas 5

Several NASA astronauts, plus Boeing test pilot Chris Ferguson, recently participated in a training session at Cape Canaveral, practicing how they would evacuate from the Atlas 5 rocket’s launch pad in the event of a countdown emergency.

The United Launch Alliance Atlas 5 rocket with the NROL-52 spacecraft aboard moved to the launch pad this morning for liftoff Saturday to serve the national interest. Liftoff is scheduled for 3:31 a.m. EDT (0731 GMT).

Two key pieces of hardware needed for NASA’s next Mars rover — an Atlas rocket booster and sterile components of the rover’s sample collection system — recently arrived at Cape Canaveral ahead of the mission’s scheduled launch July 17.