NASA warned space shuttle Endeavour's astronauts Monday about bad landing weather as they packed to come home from their space station construction mission.

The shuttle is scheduled to touch down Tuesday morning at Cape Canaveral, Fla.

"Just to let you know, the weather's not good at the cape at the moment. We are expecting it to be poor all week," Mission Control said, adding that the problems were high wind, low clouds and possible rain.

The weather at the backup landing site in Southern California, though, looks good all week. "So we're going to keep that in our hip pocket," Mission Control said.

Endeavour's undocking from the international space station Sunday cleared the way for Russian Soyuz spacecraft carrying two Russian cosmonauts and California millionaire Dennis Tito, the world's first space tourist. The Soyuz docked at Alpha as planned early Monday.

The seven shuttle astronauts spent Monday testing flight control services and steering jets and stowed away equipment used over the past 11 days in orbit in anticipation of landing. They accomplished their major objective last week: delivering and installing a billion-dollar robot arm for space station Alpha.

Crippling computer troubles aboard Alpha kept Endeavour there an extra day. Last week the two backups to a command-and-control computer critical to operating the new Canadian-built arm repeatedly failed.

Mission Control engineers scrambled for four days to fix them while the station and Endeavour crews unloaded Italian-built cargo carrier Raffaello of 6,000 pounds of supplies delivered to Alpha. The crews tested the 58-foot arm on Saturday.

Mission Control representative Larry McWhorter said it appeared that the problems centered around failed hard drives on the two backup computers. A spare computer aboard Alpha replaced one of the backups, and its hard drive had been reformatted Monday. That replacement was being loaded with software to act as a command-and-control computer.

The second backup was operating, but without a hard drive.

NASA said the hard drives contain all information necessary to control the various systems at Alpha and send commands to those systems.

Endeavour is bringing the original backup to Earth so engineers can determine what went wrong.

The three computers are on the U.S.-built Destiny lab, delivered to the station in February. If all three fail, mission operations director Randy Stone said Alpha could fly the way it did before Destiny arrived. Two computers on another U.S. module would suffice.

"We have a lot of options to fault down through. Some of them wouldn't be very pretty, but all of them would be safe," Stone said.

The arm, a high-tech construction crane that can walk end-over-end like an inchworm, will be used to add pieces to Alpha over the next 15 to 20 years.

On Saturday it handed off its 3,000-pound packing crate to a smaller arm attached to the shuttle. The smaller arm stowed the crate in Endeavour's cargo bay, alongside Raffaello stocked with 1,600 pounds of trash and discarded equipment, for the trip back to Earth.