Cape Canaveral, Mar 23: Endeavour's astronauts embarked on the fifth and final spacewalk of their mission Saturday, this time to attach a 50-foot (15.24-meter) inspection pole to the international space station for use by the next shuttle visitors.

Michael Foreman and Robert Behnken floated out the hatch late in the afternoon as the linked shuttle and station soared more than 200 miles (322 kilometers) above the Pacific. They planned to spacewalk the night away.

``Spacewalk No. 5 out of five. It's going to be a great one,'' said their commander, Dominic Gorie.

The shuttle astronauts used the laser-tipped inspection boom at the beginning of their 16-day mission and again Friday night to check for any damage to their spaceship. It's become a routine safety procedure ever since the 2003 Columbia accident.

Discovery will not have room for a boom when it flies in May; the Japanese Kibo lab it will transport is so big it will take up the entire payload bay. So Endeavour's astronauts needed to leave theirs behind.

Besides securing the boom to the outside of the orbiting complex, Foreman and Behnken were going to inspect a jammed rotating joint that has restricted the use of a set of solar wings for months, and take another crack at hanging some scientific experiments to the European lab, Columbus.

Behnken was unable to hook the experiments to Columbus' hull during spacewalk No. 3 earlier in the week because of some sort of interference. He took out smaller pins and cable ties this time; if the pins did not work, he planned to lash down the briefcase-size box of experiments.

As for the jammed rotating solar joint, it is filled with metal shavings because of grinding parts.

NASA has been trying since last fall to figure out what is broken and how best to fix the joint. Spacewalking astronauts inspected the joint several times before and even collected samples of the steel grit for analysis back on Earth. But five covers have yet to be removed, and that is where Foreman was going to focus his efforts.

Saturday night's spacewalk was the last major space station job for Endeavour's crew. The shuttle arrived at the orbiting complex March 12, delivering the first section of the Kibo lab and a Canadian robot with 11-foot (3.35-meter) arms that is designed to assist future spacewalkers.

Endeavour is scheduled to undock from the space station on Monday night and land back at Kennedy Space Center on Wednesday night. The shuttle will have spent 12 days at the station _ the longest shuttle visit ever.