Live coverage: Atlas 5 countdown and launch journal

A NASA space telescope studying X-ray emissions from a nearby galaxy has discovered the brightest pulsar ever detected, the fast-spinning remnant of a collapsed star that shines so intensely it was initially mistaken for a massive black hole, a possible “missing link” between compact stellar-mass black holes and the unseen monsters lurking at the cores of many galaxies.

This is the launch timeline to be followed by the Atlas 5 rocket’s ascent into orbit from Cape Canaveral with NASA’s Tracking and Data Relay Satellite-M. Launch is scheduled for Friday at 8:03 a.m. EDT (1203 GMT).

Soaring more than 200 miles above Earth, a Chinese spacecraft with two astronauts on-board closed in for docking with the Tiangong 2 space lab just before 1930 GMT (3:30 p.m. EDT).