Live coverage: Atlas 5 countdown and launch journal

Poised for its one and only satellite launch of the year, the National Reconnaissance Office will conduct a hush-hush flight Thursday using a United Launch Alliance Atlas 5 rocket from California.

Culminating years of construction and testing, a $1.2 billion satellite designed to spot and track enemy missiles threatening the United States homeland, its deployed military forces abroad or allied nations will ascend to a surveillance post in space Thursday.

United Launch Alliance has completed stacking of the major elements of the Atlas 5 rocket assigned to power NASA’s Perseverance rover toward Mars, but the mission’s launch date has been pushed back three days to July 20 after teams repaired an issue with a crane in the Atlas 5’s assembly building.