The shuttle was previously scheduled to undock Monday from the ISS and to arrive on Wednesday in Florida, but the nine-day mission to the ISS was cut short and Endeavour undocked on Sunday after US space agency NASA feared Hurricane Dean could strike its mission control in Texas.

Dean was expected to make landfall on Mexico's Caribbean coast Tuesday morning, possibly at category five strength. Under the new schedule Endeavour’s first landing opportunity will be on Tuesday at 12:32 p.m. at Kennedy Space Center, Fla., with the deorbit burn occurring at 11:25 a.m. A second opportunity is available at the Florida spaceport at 2:06 p.m. The deorbit burn would occur at 1 p.m.

"Hopefully, we'll have acceptable weather and it will be a really good day," commander Scott Kelly radioed from orbit.

The earlier landing simplifies the evacuation of the Johnson Space Centre in Houston, if necessary.

Edwards Air Force Base in California and the White Sands Space Harbor in New Mexico will not be activated Tuesday as possible landing sites.

"It's really important that we keep our options open as long as it's practical," Matt Abbott, NASA's lead shuttle flight director said. "We've been watching this storm kind of brewing for a couple of days and everyone has been aware that it's developing ... we need to be prepared to respond."

"Our objective is really to get the mission completed, first and foremost, from here in Houston," he added.

According to NASA, the seven astronauts onboard Endeavour have completed on Monday morning a full test of systems and engines that will be used for re-entry and landing. Other preparations included stowing equipment and a 30-minute deorbit briefing. The crew also had some off-duty time to prepare for Tuesday's landing opportunities.

The Endeavour’s crew spent almost nine days at the international outpost. They continued the on-orbit construction of the station and transferred tons of cargo between the two spacecraft. The STS-118 crew conducted four spacewalks at the station. The two major objectives were the installation of the S5 and the replacement of a failed attitude control gyroscope.

On Sunday by successful completing the last spacewalk the astronauts Williams and Anderson had bumped up the total time for STS-118’s four spacewalks to 23 hours and 15 minutes, despite the fact that their spacewalk was reduced with two hours in order to allow the early hatch closing and departure. Saturday's excursion was the 92nd spacewalk devoted to station assembly.

Though, the Endeavour team's missions have not been spared from adventures. The third spacewalk of Endeavour’s mission has ended earlier than expected after damage of an astronaut's glove was detected. US astronaut Rick Mastracchio noticed damage to the outer layer of his spacesuit's glove during a routine scan with his helmet cam. Both gloves had damage, however, it was a small penetration in the outer layer of the left thumb that caused flight controllers to make the decision to end today’s spacewalk early.

Last week on Thursday NASA mission managers in Houston decided not to repair the space shuttle Endeavour’s heat shield. The mission managers have determined that damage to a small section of Endeavour’s heat shield poses no threat to crew safety or mission operations.

An earlier inspection revealed that the gouge, located near the ship's right wheel well, is 30.5 x 25.5 millimeters (1.2 x 1.0 inches) large (smaller than initially reported) and 28.5 millimeters (1.12 inches) deep. During take off, debris tore a gash in tiles on the underside of the shuttle.

According to NASA a computer analysis completed last week and based on the data sent in after the inspection indicated the aluminum behind the damaged tile would not exceed 350 degrees, which would be acceptable.

"After hours of reviewing data and imagery collected during the inspections by the (shuttle) crew, the managers decided the damage did not pose a safety risk to the crew or Endeavour," a NASA statement said.

The damage is not enough to risk a catastrophic failure of the shuttle's heat shield, like the one that destroyed the shuttle Columbia on re-entry in February 2002, but the process of underside repairs during a spacewalk would have entailed risks for the astronauts.

In a news conference held before undocking, the crew of the Space Shuttle Endeavour said it agrees with NASA decision not to repair damage the shuttle sustained during takeoff.

"We're certainly concerned that if we did the repair we could do more damage to the underside of the orbiter," Commander Scott Kelly said. "The shuttle crew and the staging crew agreed with the decision not to the repair."

The Endeavour’s crew includes astronaut Barbara Morgan, a former teacher who was the backup to fellow educator Christa McAuliffe, who died in the shuttle Challenger's explosion on takeoff in 1986.
Barbara Morgan’ association with NASA began more than 20 years ago. Initially Morgan was selected as the backup candidate for the NASA Teacher in Space Program on July 19, 1985.
From September 1985 to January 1986, Morgan trained with Christa McAuliffe and the Challenger crew at NASA’s Johnson Space Center, Houston, Texas. After the Challenger accident Morgan resumed her career as teacher, but she was selected by NASA as a mission specialist in January 1998.