Mid June 2010, Soyuz 23S delivered an additional three crewmembers to ISS to bring the crew size for the remainder of Expedition 24 to six. These were NASA flight engineers Doug Wheelock and Shannon Walker, and cosmonaut Fyodor Yurchikhin.
In addition to the planned three spacewalks, one in Russian Orlan space suits and two in U.S. Extravehicular Mobility Units (EMUs) the crew were involved with additional spacewalking tasks that involved the removal of and successful replacement of a failed ammonia pump module. The planned EVA’s (extravehicular activities) required the crew to install a power and data grapple fixture (PDGF) on the exterior of the Zarya module, which provides a handhold for the space station’s robotic arm on the Russian side of the station; and to deploy the new Rassvet mini research module on Zarya for permanent operations in space. Rassvet’s primary use is for cargo storage and as a docking port for visiting spacecraft. The first docking with this module was used in mid June when Soyuz 23S arrived at ISS delivering Wheelock, Walker and Yurchikhin.
Expeditions 23 and 24 finished delivering the final facilities to enable full use of the International Space Station for research, technology development, and education, putting the potential of space to work for the people of Earth. With nearly 130 integrated investigations from nearly 400 scientists around the globe, scientific throughput has quadrupled during the transition from assembly to the era of utilization. Forty-five of these experiments are new to the station, eight are associated with the station’s role as an official U.S. National Laboratory, and 55 are sponsored by NASA’s international partner agencies (the Canadian Space Agency (CSA), the European Space Agency (ESA) and the Japan Aerospace Exploration Agency (JAXA)). Another 40 experiments are sponsored by the station’s fifth partner, the Russian Federal Space Agency (RSA). All station partners cooperate and coordinate their research investigations, and many investigations include international teams of scientists. The investigations cover human research; biological and physical sciences; technology development; Earth observation, and education. In the past, assembly and maintenance activities have dominated the available time for crew work. But as completion of the orbiting laboratory nears, additional facilities and the crew members to operate them is enabling a measured increase in time devoted to research as a national and multinational laboratory.
Expedition 24 Commander Alexander Skvortsov, accompanied by Flight Engineers Tracy Caldwell Dyson and Mikhail Kornienko, was at the controls of the Soyuz TMA-18 spacecraft as it undocked from the space station's Zvezda module on September 24, 2010. Following a normal descent, the crew landed early on September 25, 2010, near Arkalyk, Kazakhstan.