(AP) -- NASA has begun the launch countdown for space shuttle Discovery.
The countdown clocks began ticking late Friday night. Discovery is scheduled to blast off early Tuesday morning. Forecasters put the odds of acceptable conditions at 70 percent.
Discovery and a crew of seven will deliver about 17,000 pounds of supplies and equipment to the international space station.
NASA test director Steve Payne said the only outstanding issue is a shuttle power controller that had to be replaced, but so far, all the testing looks good.
NASA has until Aug. 30 to launch Discovery, otherwise the shuttle will have to get in line behind a Japanese cargo ship and a Russian Soyuz spacecraft that are set to fly in September.
©2009 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.
Explore further: Lockheed Martin successfully mates NOAA GOES-R satellite modules