By MARCIA DUNN AP Aerospace Writer
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 whipped through a variety of chores outside the International Space Station on Tuesday, making their fourth and final spacewalk in under a month. They routed cables, hooked up a tool chest and removed thermal shielding from a docking port that will house a commercial airlock later this year. 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.