HOUSTON -- After the departure of the space shuttle Atlantis, Expedition 15 Commander Fyodor Yurchikhin and Flight Engineer Oleg Kotov returned to their daily operations aboard the International Space Station this week, while newly arrived Flight Engineer Clay Anderson began conducting scientific experiments.

Atlantis landed in California June 22 after delivering a new starboard truss segment and a set of solar arrays to the station. Returning on the shuttle was Sunita Williams, who lived and worked aboard the orbiting complex for six months. Anderson succeeded Williams on the station and arrived with the Atlantis crew on June 10.

Anderson performed his first Saturday Science activity on June 23, showing younger television viewers how Newton's laws apply to sports activities, even in the microgravity of space.

On Monday, Anderson began work with a nutrition experiment. He collected blood and urine samples and began logging all of the food and drinks he consumed. The experiment tracks many vitamins and minerals essential for good health. It is the most comprehensive in-flight study to date of human physiological changes during long-duration spaceflight. Also, Anderson and Kotov did a medical emergency exercise, and Yurchikhin replaced one of three transmitters on the Russian Regul communications system.

The crew inspected the lights and power systems and performed a routine examination of the windows on the Russian Zvezda service module on Tuesday.

Wednesday was filled with science. Each crew member completed medical tests and periodic fitness evaluations, and worked with a variety of Russian experiments. Kotov spent about two hours using a multimeter to do resistance checks on the computer system in the Zvezda service module. The two major computer systems there continue to function well, with two of three "lanes," or data paths, of each system operating.

Anderson wore an acoustic dosimeter on Thursday to check station noise levels. He also worked with the Microgravity Science Glovebox in an unsuccessful effort to complete a leak check. Troubleshooting continues. Yurchikhin and Kotov spent more than two hours with the Russian Profilaktika experiment, which looks at measures to counteract the long-term effects of microgravity. Yurchikhin also worked with the Matryoshka radiation detection experiment and Kotov inventoried medical equipment inventory.

On Friday, Anderson did a routine cleaning of spacesuit cooling loops. Yurchikhin and Kotov worked in the Russian segment, replacing current converter units in the Zarya module -  June 29, 2007