An unmanned SpaceX rocket is on the launch pad at Cape Canaveral. It's scheduled to blast off at 4:58 PM today (2058 GMT) with more than 2 tons of supplies.
NASA spent much of the weekend debating whether to proceed with the launch. A critical backup computer failed outside the space station Friday. Mission managers decided yesterday to stick with the plan after making sure everything would be safe.
The Dragon supply ship holds a gasket-like material for next week's computer replacement. Spacewalking astronauts will perform the job April 22. This new material was rushed to the launch site following the outage.