The culprit
Above is a foam model from the Shuttle’s left bipod ramp. The area above the black line is presumed to approximate the area and mass of the foam that struck Columbia’s left wing. Incredibly, the chunk weighed no more than 1.67 pounds.
As the investigators learned, damage from falling debris was a fixture of every Shuttle flight. What’s more, STS-107 marked the seventh occurrence in which falling foam was recorded. NASA engineers didn’t believe it was possible for such a low-density object to cause so much damage, but at speeds reaching more than 500 miles per hour (804 km/hr), the tumbling foam, packed with extra rotational energy, exacted considerable damage to the wing’s reinforced carbon panel.
