QUESTION:
What is the top speed that the shuttle ever reaches?

ANSWER from Eric Hammer on April 10,1997:
The top speed that the Space Shuttle reaches is during the orbit
portion of the mission.  During the ascent, the shuttle continuously
increases its speed until it is going fast enough to maintain its orbit.

The first thing the shuttle does when its time to come home is slow
itself down, ultimately until it comes to rest on the runway.

The orbital speed is determined by the altitude that the Space Shuttle
operates.  The operational altitudes that most missions use is between
140-310 nautical miles.  The lower the spacecraft is, the faster it
needs to go to maintain the orbit.  Likewise, as the spacecraft flies at
higher altitudes, less velocity is required to maintain its orbit.
In general, the Space Shuttle top speed is always around 17,500 miles
per hour, or 25,700 feet per second.  That means the Space Shuttle
travels almost 5 miles every second!