Tiles are removed for replacement on Columbia's starboard side. Photo: Spaceflight Now

Among the other improvements lined up for Columbia are Global Positioning System navigation gear, beefed up cooling radiators and an exterior paint job to replace the NASA "worm" with the "meatball" symbol.

Columbia will receive an advanced navigation system relying on the U.S. Air Force's Global Positioning System satellite network -- a constellation of 24 spacecraft orbiting 11,000 miles above Earth. The GPS system will allow the shuttle to more accurately pinpoint its precise location during flight. If NASA becomes comfortable with the GPS system, it could one day replace the current shuttle navigation system.

For safety, the shuttle's radiators located on the payload bay doors are being beefed up to protect against micrometeorite impacts. The radiators will now seal off areas punctured by a micrometeorite, stopping freon from escaping into space and allowing the shuttle mission to continue.

The freon is used to cool the shuttle's electronics, and the old system would have forced an immediate emergency landing if a radiator was damaged.

Also, sections of the crew compartment floors are being strengthened to protect the astronauts during a "hard" landing. The upgrade will allow the floors to withstand 20g's, or 20 times Earth's gravity.

Boeing is also installing a new radio and wireless video system to permit additional communications relay during spacewalks.

Columbia's unique paint scheme includes an American flag and "USA" but NASA's new look as seen on shuttle Endeavour now includes the agency's Meatball logo. Photos: NASA

Finally, the most noticeable change to Columbia will be removal of two NASA "worm" logos painted on the payload bay doors. The NASA "meatball" logo will be added to ship's side as a replacement, under the orders of agency chief Dan Goldin.

As for Columbia's wings, which have a unique design with "USA" on one and an American flag on the other, there is conflict about what will be done. Boeing says they have not been told to remove Columbia's special look, giving it the same design as the other shuttles. But NASA said last year that Columbia must appear like its sisterships.

NASA is looking at even more upgrades for the future to reduce the risks of flying the space shuttle in half by 2005.

"The exploration of space never be without risk. But it is mandatory that we use the best technology, human expertise and human dedication available to minimize that risk at all times," said astronaut John Young, commander of the first space shuttle mission aboard Columbia.

Plus, the space agency wants to keep the shuttle around for another decade or two and developing new systems will replace obsolete parts that won't be available anymore.