Before atmospheric entry can be analyzed, whatever is going to be coming into the atmosphere must be examined. It’s obvious that a space shuttle will be launched and put out in space. To remain out in space, the space shuttle must maintain an incredible velocity (around 8 km/s or mach 23-25) or else it will be pulled down by Earth’s gravity. This angular velocity will allow the space shuttle to maintain an orbit around Earth, thus, allowing it to remain in space.
http://www.launchpadspacecraft.com/images/shuttle_earth_orbit.jpg
A meteor will not be in orbit. From some place in the solar system, galaxy, etc. the meteor will travel through space at speeds of 60-70 km/s, about 8 times that of an orbiting space shuttle. A meteor varies in size from miniscule dust/sand like particles a few microns in diameter to some having a mass of several kilograms.
http://www.imo.net/mission_meteor.jpg