Shuttle Set to Shield Itself From Trash Bash

The increasingly alarming threat of space junk has prompted NASA to change the way space shuttle Columbia will fly during a science mission that begins today.

For the first time, a shuttle will zoom around Earth with one of its huge cargo-bay doors partly closed to shield fragile cooling loops on the interior of the doors from tiny but dangerous pieces of debris. Normally, both doors are kept wide open to let heat escape.

Columbia is scheduled to lift off at 6:35 a.m. PDT on the 16-day mission, one of the longest shuttle flights ever. Besides growing semiconductor crystals, the seven astronauts will conduct fluid, fire and potato-plant experiments.