Bad weather keeping shuttle Atlantis in orbit
The shuttle's mission had been plagued by problems from the outset, including thermal insulation torn loose during the launch.
Computers also failed on board the International Space Station, prompting fears of evacuation.
The shuttle is now expected to land either Friday or Saturday, but there is enough power to remain in orbit until Sunday.
There are back-up landing sites, but managers are hoping for a landing at Kennedy, since it would cost $US 1.7 MLN to transfer the shuttle back to Florida by jumbo jet.