Spacewalkers try to free jammed array

Two astronauts stepped outside the international space station on an impromptu spacewalk Monday to try to fold up a stubborn, accordion-like solar array.

Space shuttle Discovery's Robert Curbeam and Christer Fuglesang were assigned to get the jammed array to retract completely into a box. It was the fourth spacewalk of Discovery's flight to the orbiting outpost.

The electricity-generating array became stuck last Wednesday in the halfway-retracted position as it was being folded up by remote control. After repeated efforts to get it to retract _ including attempts to shake it loose by having an astronaut exercise vigorously aboard the space station _ NASA decided to send two cosmic mechanics out to fix it.