on february 1, "columbia" prepared to return to earth on a path that would take it over the usa from west to east. at 8:15 est, about an hour before "columbia" was due to land, it lit its engines and changed its course so that it would re-enter the atmosphere. a 13-minute video recorded in the cabin, ending eleven minutes before the loss of signal from "columbia", shows the astronauts in good spirits and unaware of the danger. as "columbia" entered the atmosphere, the air heated up around it due to the shuttle moving at extreme speeds, over twenty times the speed of sound. this air was able to enter the wing through the hole made during launch, melting through it and causing the shuttle to lose lift on that side. this loss of lift caused the shuttle to turn away from its re-entry path, tumble, and break up from the drag of the air.