docked to the International Space Station (ISS) due to the loss of the shuttle's Ku-Band antenna. April 17 (Flight Day 13 – Undocking) Space Shuttle Discovery successfully undocked from the International Space Station (ISS) at 12:52 UTC (08:52 EDT). Discovery was docked to the ISS for 10 days, 5 hours, and 8 minutes. After Discovery departed from the ISS, pilot Jim Dutton took control of the shuttle and performed a fly around of the space station. The undocking was preceded by a farewell ceremony, where shuttle commander Alan Poindexter and station commander Oleg Kotov said farewells on behalf of their crews. After undocking the shuttle crew stowed the Orbiter Boom Sensor System (OBSS) and the Shuttle Remote Manipulator System (SRMS) since they will not be needed for the rest of the flight. The crew was also informed that Discoverys heat shield was cleared for re-entry into Earth's atmosphere. April 18 (Flight Day 14 – Landing prep) On flight day 14, the crew of Space Shuttle Discovery began their final preparations for landing. The crew packed and stowed away items they no longer need for the rest of the flight. Throughout the day, commander Alan Poindexter and pilot Jim Dutton completed a series of checkouts of flight systems. These checks include 2 firings of the Reaction Control System (RCS) jets and a test of the Flight Control System (FCS). Once those checkouts were complete the pair began doing communications checkouts with the Merritt Island tracking station and tracking stations at the White Sands Space Harbor in New Mexico and Dryden Flight Research Center at Edwards Air Force Base. The crew also took time out of their day to conduct an in-flight interview with WBZ-AM in Boston, Massachusetts; the Associated Press; and KEZI-TV in Eugene. April 19 (Flight day 15 – First landing opportunity) The crew of STS-131 awoke for flight day 15 and began their deorbit preparations. These preparations include closing the payload bay doors, activating the Flash Evaporator System (FES) and getting into their Advanced Crew Escape Suits (ACES). The crew got as far as "fluid loading", where the crew consumes a set quantity of fluids to counteract the effects of gravity, in their deorbit preps. The crew was informed of the one orbit wave off about one hour prior to the deorbit burn. After the crew was told of the wave off, they held in their procedures to see