launched from Baiknour on May 5 and docked under control of the Kurs automatic system at the -X port of the Mir on May 7. For the first time in the station's history, all ports of the base block were occupied at the same time. The crew began unloading the vehicle that week, in addition to continuing their science experiments and Priroda activation. They successfully tested the new Mir interface-to-payload systems (MIPS) hardware for downlinking data to the ground and replaced three nickel-cadmium batteries in the Priroda power system. However, a power controller for the system failed, and ground controllers began monitoring and controlling battery charging. The crew finally isolated the coolant loop leak in the core module, but there was no health risk associated with the leak and repair was not immediately scheduled. Cooperative Solar Array Installed over 2 EVAs Onufrienko and Usachev left the station early on May 20 to remove the Mir Cooperative Solar Array from its stowed position on the exterior of the DOcking Module at the base of Kristall. They used the new Strela boom installed during their March 15 EVA to reach the array and move it to the Kvant module, where they positioned its cables in preparation for final installation during their next EVA. During the five hour and 20 minute EVA, they inflated an aluminum and nylon model of a Pepsi Cola can, which they filmed against the backdrop of Earth. The soft drink company paid for the procedure and planned to use it in a television commercial. On May 25, in their third space walk of the mission, the cosmonauts were outside the station for five hours and 43 minutes, completing the solar array installation on Kvant. After all connections were made, the array unfurled upon command from inside the station. Mir 21 Crew Greets STS-77 Crew All the crew members exchanged greetings with the astronauts aboard the Space Shuttle Endeavour on STS-77 and they held a conference with U.S. and Russian news media. Camera Installed on Priroda Exterior During Fourth Mir 21 EVA On May 30, Onufrienko and Usachev installed the Modular Optoelectronic Multispectral Scanner (MOMS), a German remote sensing camera, on the Priroda module. The camera, designed to collect Earth atmosphere and environment data, had been flown earlier on two Shuttle missions, STS-7 in June 1983 and STS-41B in February 1984. After the installation, Lucid activated the system by