"It's the final countdown..." When does the official countdown for a shuttle launch start?

Answer T minus 43 hours

"10, 9, 8..." Although this might be the most exciting part of the shuttle launch countdown, it actually begins at Kennedy Space Center at T-43 hours. This is to ensure that all final prep work for launch is given ample time to be completed.

Last updated 5 years ago · 1.5K views · SOURCE