The launch takes place on a milestone date, marking 20 years since the STS-114 space shuttle mission took off from Kennedy Space Center Pad 39B. The launch of Discovery on the STS-114 mission on July 26, 2005, marked the return to flight for the space shuttle after the Columbia tragedy investigation.

SpaceX Falcon 9 rocket will launch from Vandenberg in California on a NASA mission. Where are some spots to watch liftoff? Will there be a sonic boom?

About 3,870 employees have applied to depart NASA over two rounds through the Trump administration's deferred resignation program, the agency disclosed.