Debris analysis: Ice struck shuttle at launch

A curved sheet of ice that built up on shuttle Discovery's external tank prior to launch broke off at liftoff Tuesday and struck the liquid hydrogen umbilical door on the underside of the orbiter.

In a message beamed up to the Discovery astronauts earlier today, NASA mission managers told the shuttle crew that engineers would review high-resolution photos taken during the shuttle's approach to the International Space Station to determine whether any serious damage was done.

Four inches long and a one-and-a-half inches in diameter, the ice formed on a 17-inch propellant line that feeds supercold liquid hydrogen to the shuttle's main engines from its external tank.

A couple of breakaway pieces of foam also hit the belly of the ship, but the strikes came after the critical time in flight when debris can be transported with enough kinetic energy to damage shuttle heat-shield components.

You can see the details in the message beamed up to the crew: MSG019.pdf