Two signs accompanying the Delta shroud/payload fairing.
The top one reads
Mounted on top of the launch vehicle, this is the cover, or "fairing," which
protects satellites as they go through the atmosphere.
The bottom one reads
Delta 3rd Stage Engine
This is one of several types of third-stage rocket engines used on a Delta. It
is a "solid" motor, containing solid as opposed to liquid fuel, which, once
ignited, burns through to completion.