Live coverage: Atlas 5 countdown and launch journal

NASA has decommissioned a long-lived satellite launched in 2000 that demonstrated remote sensing and surveying instruments and techniques common in today’s orbiting Earth observatories.

The launch of a United Launch Alliance Delta 4-Heavy rocket from Cape Canaveral was aborted three seconds before a planned liftoff at 3:28 a.m. EDT (0728 GMT). The rocket was set to loft a classified payload for the National Reconnaissance Office, the U.S. government’s spy satellite agency.

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.