On Friday, the seven astronauts of NASA's Discovery spacecraft had the last day of practice for the upcoming mission scheduled for the end of the month. Discovery will take off on Saturday, May 31, at 5:02 p.m. from NASA's Kennedy Space Center in Cape Canaveral, Fla.

According to Mark Kelly, shuttle commander, everything is coming along smoothly: "From what I was told yesterday, the condition of the orbiter and the number of problems we've had with it have been at a historic low," he said from Discovery's launch site. "So that makes us feel really good."

The mission will take 13 days to complete; for reaching the main objective, delivering Japan's Kibo laboratory, three spacewalks will be required.

The first part of the Kibo laboratory was installed during a 16-day mission of space shuttle Endeavor, which ended in March with a rare nighttime landing at the Kennedy Space Center. It was the first mission to ever feature five space walks. The crew’s agenda also included assembling a robot, inspecting a solar-wing joint which seemed to be jammed and droping off a shuttle inspection boom.

Initially, Discovery was supposed to be launched on May 25; however, at the beginning of April, NASA announced that the launch would be delayed by six days. Due to bad weather experienced in March, Cape Canaveral’s external tank arrival was delayed by several days. This caused the push back of several processes.

For 2008, NASA is hoping to have a grand total of five shuttle flights, out of which four will be engaged in the space station’s construction and one will be a servicing mission at the Hubble Space Telescope.