The space shuttle Endeavour swooped through a sky of thick clouds touching down on Earth under heavy security Monday as it brought home a space station crew.

"We are looking forward to getting home for Christmas,'' shuttle commander Dominic Gorie said from orbit earlier in the day.

The shuttle landed as scheduled, at 12:55 p.m.

"Nice job on the approach and landing, there, Dom," Missing Control told Gorie after the spacecraft rolled to a stop.

It was a long-awaited homecoming for the International Space Station's former commander, Frank Culbertson, and his crew mates, Russian cosmonauts Vladimir Dezhurov and Mikhail Tyurin.

They had formed the third space station crew, spending 129 days in orbit.

Culbertson and his crew were in orbit on Sept. 11 and could see smoke rising from the devastation at the World Trade Center and the Pentagon from 400 kilometres up in orbit.

"That was a horrible thing to see from space, to know that terrible things were happening on Earth like that and we were so far away from our own families," Culbertson said over the weekend.

Earlier in the day, Endeavourâs crew -- which included Gorie, Pilot Mark Kelly, Mission Specialists Linda Godwin and Dan Tani, along with the returning space station crewmembers -- were awakened by the song "I'll Be Home For Christmas," sung by Bing Crosby.

The shuttle undocked from the International Space Station on Saturday, but not before performing a series of engine burns designed to push the orbiting outpost higher in order to avoid hitting a 30-year-old piece of space junk -- a task that slightly delayed the shuttle's departure.

The space junk in question was a spent Soviet-era rocket booster launched in 1971. Its just one of thousands of space objects, both human-made and natural, whizzing around the Earth at some 36,000 kilometres per hour.

NASA had the shuttle pilots fire their thrusters for 20 minutes to move the station out of harm's way. This created a gap of more than 65 kilometres between the station and the junk.

The threat of space junk is nothing new for NASA. The agency frequently replaces space shuttle windows damaged by tiny orbiting flakes of paint. In one mission in 1992, a tiny space trash particle about 100 microns in size slammed into the shuttle's window, leaving a visible impact crater.

Because of the very great speeds at which space trash travels, small pieces between 1 and 10 centimetres in size can penetrate and damage most spacecraft. According to NASA, a 10-centimetre long piece of space trash can cause as much damage as 25 sticks of dynamite.

Endeavour spent eight days at the space station, dropping off tonnes of supplies and taking on tonnes of trash and old equipment for return to Earth.