UPDATE for 7:00 PM FRIDAY, JAN. 19
All is going well so far at complex 41 as United Launch Alliance prepares its Atlas 5 for launch. Liftoff is targeted for the opening of a 40-minute window at 7:48 p.m. EST.
Live updates on WMMB will begin at 7:44 p.m. EST.
UPDATE for 7:30 PM THURSDAY, JAN. 18
A launch attempt of an Atlas 5 rocket was scrubbed within an hour of its planned liftoff time Thursday night when the United Launch Alliance team encountered a problem with propellant valve out at complex 41.
After some initial troubleshooting proved to be unsuccessful, the decision was made to send a team back out to the cleared launch pad to work on the problem there. The involved effort to make that happen would have taken longer than the available launch window, so the mission was scrubbed.
The plan for now is to be optimistic the issue can be resolved and the rocket can make another attempt to fly on Friday night. We haven't seen an official launch time for a Friday night, but it shouldn't change by much -- if at all -- from 7:52 p.m. EST.
It would also seem unlikely that a 24-hour delay in launching the Atlas will have any effect on SpaceX's plans to test fire the 27 main engines of its Falcon Heavy rocket, now sitting just a little further north from the Atlas 5 complex.
Should any of these facts change, or our speculation become more clear, we will update this page.
-- Jim Banke