Physical Fixes

NASA made48 changes to the shuttle to reduce its vulnerability to minor debris hits and to improve its ability to detect and repair damage. To verify the fixes, NASA must obtain at least three useful views of the shuttle during the first two minutes of flight. It has augmented its camera network on the ground and on the shuttle. It also has made spy satellite imaging of orbiting shuttles mandatory through an agreement with the National Imagery and Mapping Agency.

External fuel tank critical debris sources eliminated:

• Replaced foam insulation with heaters at orbiter attach points.
• Modified liquid oxygen fill points to prevent ice buildup.
• Redesigned solid rocket booster bolt catchers.

Orbiter thermal protection improved:

• Carbon-composite wing leading-edge panels.
• Main landing gear doors (in rear underbelly).
• Forward steering jets.
• Thicker side windows.

Orbiter health monitoring enhanced:

• Temperature and impact sensors on wing leading edges, accelerometers throughout.