Washington - Thunderstorms kept the space shuttle Discovery from landing late Thursday at Florida's Kennedy Space Centre.

The landing was originally been set for 7:05 pm (2305 GMT) before being pushed to 8:40 pm (0040 GMT Friday) because of weather concerns. US space agency NASA decided to scrap Thursday's launch altogether when the storm threat lingered.

NASA said it would try again during a launch window beginning at 6:48 pm (2248 GMT) from Cape Canaveral on the Atlantic Coast, where the space centre is located.

Weather concerns remain for Friday's landing, which could force shuttle mission control to order a landing on the other side of the United States, at Edwards Air Force Base in the California desert.

Stormy weather is common during summer evenings in sub-tropical Florida.

   The crew of six US and a Swedish astronaut delivered to the International Space Station a new sleeping compartment and a treadmill named for television comedian Stephen Colbert, as well as two racks for scientific experiments and a freezer to store experiments set to be sent back to Earth.

One of the racks will be used to conduct research on metals, semiconductors, crystal, glass and other materials in microgravity. The other will be used to study liquids and gels in space.

During three spacewalks, astronauts replaced an empty ammonia tank and made other repairs.

-- IANS