Washington, Sep 9 (DPA) The space shuttle Discovery undocked from the International Space Station (ISS) Tuesday after delivering supplies and equipment to boost the capacity of the orbiting laboratory.

Pilot Kevin Ford backed Discovery away from the station at 1926 GMT for the trip back to Earth. The shuttle is scheduled to land at Kennedy Space Centre in Florida Thursday.

The crew of six US and a Swedish astronaut brought 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 removed an empty ammonia tank and installed a new one and made other repairs.