NASA scrapped the launch of the space shuttle Discovery and its seven-member crew early on Tuesday, announcing a 24-hour delay due to unfavourable weather conditions.

Just minutes before the shuttle was due to blast off from the Kennedy Space Center in Cape Canaveral, Florida, toward the orbiting International Space Station, the US space agency called off the launch and said it would make another attempt Wednesday at 1.10am.

Discovery is to deliver equipment for a new bedroom, a treadmill, a freezer, food and other supplies. It will also be dropping off the newest ISS resident ? US astronaut Nicole Stott.

Stott will be taking over from engineer and fellow American Tim Kopra, who has been aboard the ISS since July and is returning to Earth with Discovery.

The shuttle crew, led by Commander Rick Sturckow, will be delivering 6.8 tons of cargo transported in a pressurised module called Leonardo that was built by the Italian space agency.

Two astronauts from the team are scheduled to conduct three spacewalks of six and a half hours each during the 13-day mission, which is the fourth of five planned for the shuttle this year. The last is scheduled for November.

One of the key goals of the space walks is the replacement of an old liquid ammonia tank, which will be substituted with a new 800-kilogram replacement brought aboard Discovery. The substance is used as a coolant.

The astronauts will also be retrieving experiment equipment from the outside of the ISS and returning it to Earth for processing.

The new freezer will store samples of blood, urine and other materials that will eventually be taken back for study on the effects of zero-gravity.

The COLBERT treadmill, named after popular US comedy talkshow host Stephen Colbert, will be the second aboard the ISS. Exercise is key for astronauts spending long periods of time in space, where zero-gravity can result in muscle atrophy.

Among the seven-member crew is veteran European astronaut Christer Fuglesang (52) of Sweden.

The shuttle flight also is the first with two Hispanic astronauts: veteran mission specialist John "Danny" Olivas (44) of El Paso, Texas, and rookie Jose Hernandez (47) of Stockton, California.

Hernandez will provide bilingual Twitter updates from space, via Twitter.com.

The mission will be the 128th for the space shuttle program, and the 30th mission to the ISS.

Once the Discovery mission is complete, just six more shuttle flights remain before NASA's three shuttles are retired in September 2010.

The International Space Station is a project jointly run by 16 countries at a cost of $100-billion ? largely financed by the United States.