CAPE CANAVERAL, Fla. (AP) — Astronauts are squeezing in one last spacewalk before turning their attention to the all-important end to SpaceX’s first crew flight. NASA’s Bob Behnken and Chris Cassidy floated out of the International Space Station on Tuesday, their fourth and final spacewalk in under a month. Instead of swapping batteries, they’ll be routing cables and hooking up a tool storage chest. In less than two weeks, Behnken and Doug Hurley will depart the orbiting outpost in the same SpaceX Dragon crew capsule in which they arrived at the end of May. SpaceX is aiming for a splashdown off the Florida coast in early August.