performed their 6-hour EVA in Atlants' cargo bay and on the exterior of the Mir Docking Module. Their major task was to secure four experiment canisters to handrails on the docking Module. The experiments, collectively called the Mir Environmental Effects Payload (MEEP), were designed to record data on orbital debris, and to test potential International Space Station materials by exposing them to the low Earth orbit environment. The four passive experiment canisters would be retrieved by a later STS crew after almost 2 years of data collection. During their work on the Docking Module, the astronauts also evaluated new tether hooks and foot restraints that could be sued on both Mir and Shuttle Orbiter exteriors, prototypes of International Space Station EVA equipment. They also retrieved the Mir-mounted camera that had been used in docking alignment during STS-74 in November 1995. Atlantis Leaves Mir Again The STS-76 and Mir 21 crews bid each other farewell on the morning of March 28. They closed the hatches to their spacecraft, and the astronauts began preparations for undocking and return to Earth. With the steering jets to both spacecraft shut down, Atlantis separated from the Mir Docking Module. Then Chilton reactivated the jets and slowly moved away from Mir. At 600 feet out, he began a fly-around, circled the station twice while the crews took pictures of each other's spacecraft, then moved to another orbit. April 1996 - A New Module for Mir Mir 21 Continues with Full Crew The daily flight plan, or cyclogram, for the Russian-U.S. crew was provided 4 days ahead of schedule by TsUP. A group of NASA science experts in Moscow served as consultants on science activities. The first week after Atlantis' departure, the crew focused on the Optizon Liquid Phase Sintering Experiment (OLiPSE), processing 70 samples of different metals at high temperatures. The crew also conducted life sciences research and Earth observation photography. Space Acceleration Measurement System (SAMS) monitors were placed throughout the station to record movement that might disrupt experiments. Radiation dosimeters in various locations provided another measurement of the station's internal environment. A leak in a coolant loop in the core module was detected in mid-April, but the crew was unable to find the exact location. That loop was turned off and the alternate loop was used. The Priroda Module The long-awaited launch of Priroda, earlier announced for March 10 so that the module would be