en Cuevana 3. The complex engineering challenges that make re-entry into the earth's atmosphere so dangerous. Scientists have labored for years to bring a crew safely home in what is essentially a meteorite, wrapped in a cocoon of fire, hurtling towards earth six times faster than the fastest bullet. Scientific experts from NASA explain the significance of Columbia's events as they unfolded, offer insights into what may have caused them and how those key events contributed to the shuttle’s ultimate destruction.