Astronaut Peggy Whitson, Expedition Five flight engineer, floats near the Microgravity Science Glovebox in the Destiny laboratory on the International Space Station. Photo: NASA

The new Expedition Five crew's main science activity this past week involved activation and maintenance of the new Stelsys liver cell experiment ferried to the Space Station by Space Shuttle Endeavour recently.

Liver cells have remained frozen in a liquid nitrogen thermos-type container since launch on June 5. On Tuesday, the crew transferred liquid nutrient pouches, in which the liver cells will be processed, from a refrigerator to an incubator. Today and again on Thursday, the crew  will be injecting the cells into the nutrient pouches in the incubator to begin a reactivation process.

"After two, six, 24, and 48 hours, the incubation process in different cell cultures will be stopped by transferring the processed cells to a freezer. On Friday, the last set of cells will complete processing and the experiment will be concluded," StelSys President and CEO Dr. Paul Silber said. "Cellular products will be analyzed upon the return of the samples to Earth on the STS-112 mission."

One of the specialized functions of the human liver is to break down drugs or toxins into less harmful and more water-soluble substances that are more easily excreted from the body. The StelSys experiment ­ a joint study by NASA and Baltimore-based biotechnology research company StelSys, LLC - will test this function of human liver cells in the microgravity environment of the Station and compare the results to the typical function of a similar experiment conducted on Earth.

The findings of this experiment will provide information about the effects of microgravity and shear force on proper function of human liver cells as well as maintaining the health of humans living and working in space. Research in this area could lead to earlier and more reliable drug candidate screening for patients in need of liver and kidney treatments prior to transplant. It could also accelerate development of new life saving drugs by pharmaceutical companies.   The experiment was designed by StelSys scientists and is managed by the Cellular Biotechnology Program Office at NASA's Johnson Space Center in Houston.

A variety of other new Expedition Five experiments are functioning normally this week. The Protein Crystal Growth Single Thermal Enclosure System (PCG STES) experiment was activated June 9. The Advanced Astroculture (ADVASC) experiment was activated June 11, and the science team reported this week that all the soybean plants have sprouted and are visible from images made by a camera within the ADVASC growth chamber.

The Solidification Using a Baffle in Sealed Ampoules (SUBSA) and the Pore Formation and Mobility Investigation (PFMI) experiments are awaiting setup and activation next month of the new Microgravity Science Glovebox (MSG) facility. These two experiments are studying production of semiconductor materials and the formation of molten materials in space. Both require use of a furnace and take advantage of the enclosed hands-on workspace of the Glovebox. The Glovebox facility was designed and built by the European Space Agency (ESA) based upon science and design requirements formulated in a cooperative arrangement between NASA and ESA. Also awaiting activation is the Microencapsulation Electrostatic Processing System (MEPS), and new samples in the Zeolite Crystal Growth (ZCG) experiment, which requires a 20-hour post-activation period of minimum microgravity disturbance.

The crew reported last Friday that they completed EVA Radiation Monitoring (EVARM) sessions for all three of last week's spacewalks by STS-111 crewmembers Franklin Chang-Diaz and Philippe Perrin. This experiment uses dosimeter badges worn inside astronauts' spacesuits to measure radiation absorbed by various areas of the body during spacewalks. Other planned human life sciences investigations include Renal Stone and the Pulmonary Function in Flight experiments devoted to a potential preventative for kidney stones and improving lung function in space crews.

The first Crew Earth Observations (CEO) photography subjects were transmitted to the Station on Monday, including dust and smog over the Eastern Mediterranean, air quality over Italy and the U.S. eastern seaboard, high central Andean glaciers, and icebergs in the Gulf of St. Lawrence.

Aboard Space Shuttle Endeavour for return to Earth are several completed Expedition Four Station experiments including: Protein Crystal Growth Enhanced Gasseous Nitrogen dewar, Commercial Protein Crystal Growth High Density, Commercial Generic Bioprocessing Apparatus, Experiment on Physics of Colloids in Space and the Biomass Production System.

Editor's Note: The Payload Operations Center at NASA's Marshall Space Flight Center in Huntsville, Ala., manages all science research experiment operations aboard the International Space Station. The center is also home for coordination of the mission-planning work of a variety of international sources, all science payload deliveries and retrieval, and payload training and payload safety programs for the Station crew and all ground personnel.