**The space shuttle Discovery is being prepared for an early morning launch to the International Space Station (ISS).**Discovery is scheduled to lift off at around 0621 local time (1121 BST) from Florida’s Kennedy Space Center.
It will haul equipment and supplies to the station in a container called a multi-purpose logistics module (MPLM).
Three spacewalks are planned, in which astronauts will carry out maintenance and retrieve an experiment from the outside of the space station.
Despite anomalies seen in recent ground tests of shuttle hardware, Nasa’s shuttle mission management team on Saturday gave a unanimous “go” for launch.
Engineers said the anomalies spotted during tests of booster hardware were unlikely to affect launch safety.
Mike Moses, the space shuttle launch integration manager, said: “We’re really excited about this mission and the science we’ll be able to get on board for the ISS to do what it needs to do and demonstrate its true ability as a national laboratory.”
Pete Nickolenko, space shuttle launch director, said: “Everything is in good shape. The team is doing what it does best and we’re on track and ready to go for Monday.”
The shuttle weather officer Kathy Winters said there was only a 20% chance of unfavourable weather - in the form of morning fog - on Monday.
The mission is due to include three spacewalks, each lasting around six-and-a-half hours.
Spacewalkers Rick Mastracchio and Clay Anderson will replace one of the space station’s gyroscopes, which has failed, and switch an ammonia tank.
Ammonia is used to move excess heat from inside the space station to the radiators outside.
The astronauts will also retrieve a seed experiment that was placed on the exterior of the Japanese laboratory, Kibo.
The pressurised MPLM, dubbed a “moving van” by Nasa, will deliver around 7,700kg of cargo to the station, including supplies, a new crew sleeping quarters and science racks which will be transferred to the station’s laboratories.
Only four shuttle flights remain - including this one - before the fleet is retired later in 2010.
On Friday, a Soyuz spacecraft carrying Nasa astronaut Tracy Caldwell Dyson and Russian cosmonauts Alexander Skvortsov and Mikhail Kornienko launched from Baikonur Cosmodrome in Kazakhstan.
The three crew members are scheduled to docked with the ISS on Sunday morning (BST). During their stay, the trio will carry out experiments and support two shuttle missions to the space station.
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