JSC2011-E-016370 (March 2011) --- Computer-generated artist?s rendering of the International Space Station as of March 2011, during which space shuttle Discovery (STS-133/ULF5) delivers the ExPRESS Logistics Carrier 4 (ELC4) and Permanent Multi-Purpose Module (PMM). European Space Agency's ?Johannes Kepler? Automated Transfer Vehicle-2 (ATV2) is docked to the Zvezda Service Module?s aft port. The Japanese Kounotori2 H-II Transfer Vehicle (HTV2) is linked to the Harmony node?s zenith port. Photo credit: NASA or National Aeronautics and Space Administration