Shuttle safety improvements to cost US$280m says Nasa

Nasa says safety improvements to its space-shuttle programme after the Columbia accident will cost at least US$280 million ($445 million).

It also released a summary of the hundreds of safety recommendations it has received from inside and outside the space agency since the first version of its return-to-flight plan came out two months ago.

They include shrink-wrapping the external fuel tank and insulating the tank on the inside rather than the outside to prevent chunks of foam from breaking off and striking the space shuttle, as happened with Columbia.

The three remaining shuttles have been grounded since Columbia disintegrated on February 1, killing all seven astronauts on board.