More modifications approved for Discovery's external tank

NASA today approved additional work to strengthen all of the support beams on the mid-section of shuttle Discovery's external tank.

Managers had already approved adding metal strips called "radius blocks" to 32 of the beams, called "stringers," located in areas that absorb the most stress during flight.

Radius blocks will now also be added around the rest of the intertank's circumference. Engineers determined that adding the hardware wouldn't cause any unintended effects.

The intertank has a total of 108 stringers, which are U-shaped, vertical braces measuring 21 feet in length.

In addition to the first 32 approved for modifications, five have undergone separate repairs for cracks.

That leaves another 71 approved for modification today.

The decision apparently includes eight stringers determined to be made from a stronger aluminum alloy than the "mottled" kind that cracked, and were not at first thought to require additional support.

NASA has scheduled a press conference at 2 p.m. EST Tuesday to discuss Discovery's status for a launch targeted for no earlier than Feb. 24.

Participating are Bill Gerstenmaier, associate administrator for Space Operations; John Shannon, shuttle program manager; and Mike Suffredini, International Space Station program manager. Watch it live here by clicking the NASA TV box at right to launch a viewer.