Snapshots from Atlas 5 launch

A United Launch Alliance Delta 4 rocket went through a practice countdown and fueling exercise this week to prepare for its Aug. 19 liftoff to deliver a pair of orbital surveillance satellites into space.

A balky interplanetary seismic instrument that ran into technical problems in 2015, forcing a two-year delay in the launch of NASA’s InSight lander to Mars, cleared a major test last week after engineers redesigned part of the sensor package, boosting confidence that the mission will be ready to blast off in May 2018.

With as few as 15 more launches on the calendar over the next five years, the rocket name “Delta” that has been serving the U.S. and international customers since 1960 could permanently fade into history.