Wednesday, December 29 2004 17:04 Hrs (IST) - World Time -

Washington: In a major step toward resuming launches of the space shuttle, NASA officials said today (Dec 29, 2004) they have completed improvements that will prevent the falling debris problem that destroyed space shuttle Columbia and killed seven astronauts.

The first improved and redesigned tank is scheduled to be shipped from the Michoud Assembly Facility near New Orleans on Friday (Dec 31, 2004) and will arrive at the Kennedy Space Centre five or six days later. It will then be further tested, mounted on space shuttle Discovery and readied for a launch in May or June, officials said.

Sandy Coleman, NASA's external project manager, said that testing of improvements on the tank "gives us confidence that problems like what happened on Columbia will not happen again."

"This is the safest, most reliable tank NASA has ever produced," Coleman said today in a telephone news conference from the Marshall Space Flight Centre in Huntsville, Alabama.

The changes in the external tank add less than 68 kilograms in weight. The added costs are still being tallied, said Coleman. The old style fuel tanks cost about $ 40 million and Coleman said that the new tank would be more expensive.

The external tank contains liquid hydrogen and oxygen, which are the propellants used by the shuttle's main rocket engines during launch. The super-cooled propellants cause the formation of ice on the outside of the tank as the shuttle is prepared for launch.