Human cell tissue research that could contribute to the study of cancer, heart diseases and AIDS, has kept the new Expedition Four crew busy aboard the International Space Station during the past week.

Cell research using the Cellular Biotechnology Operations Support System was one of the major crew activities on Sunday, Monday and Tuesday, Dec. 16-18. One of the most crew-intensive experiments, the cell research requires the crew to inject cells into 32 containers of nutrient solution, place them in an incubator and then periodically remove nutrient solution for analysis and re-inject fresh growth fluid. At the end of the experiment, the crew must stop growth and inject a preservative into the cell containers. The crew activated cell growth on Sunday. Since then, the crew has continued to analyze cell growth and replenish the nutrient solution. Additional experiment work was planned for Dec. 21, Dec. 24 and Dec. 27.

Cells being grown on this mission include human renal cells, blood cells and tonsillar cells. In microgravity, cells can be cultivated into healthy, three-dimensional tissues that retain the form and function of natural, living tissue. On Earth, studying normal growth and replication of human cell tissue outside living organisms is difficult, because most cells cultivated outside the body form flat, thin specimens that limit insight into the way cells work together.

Scientists from Tulane University VA Medical Center, New Orleans, Harvard University, Cambridge, Mass., and National Institutes of Health, Bethesda, Md., are participating in this experiment, managed by the Cellular Biotechnology Program Office at NASA's Johnson Space Center in Houston.

The Microgravity Acceleration Measurement System, an experiment that measures vibrations aboard the station, recorded the Saturday, Dec. 15, Shuttle undocking. This information is used by scientists planning experiments that require a very vibration-free environment.

Research operations also resumed on Monday, Dec. 17 with the Space Acceleration Measurement System (SAMS), Active Rack Isolation System ISS Characterization Experiment (ARIS-ICE) and the Experiment on Physics of Colloids in Space (EXPPCS). EXPPCS conducted a 48-hour test run on Tuesday and Wednesday, Dec. 18-19.

The first questionnaires of the Crew Interactions experiment to be completed by the Expedition Four crew were filled out by Dan Bursch on Tuesday, with Yury Unufrienko and Carl Walz scheduled to complete their questionnaires on Friday, Dec. 21. The computer-based experiment, which includes ground controllers as well as Station crews, will identify and characterize important interpersonal and cultural factors that may affect the performance of the crew and ground support personnel during Space Station missions.

The Protein Crystal Growth-Single Thermal Enclosure (PCG-STES) Unit 10 experiment continued to operate normally this week after activation on Dec. 6. An identical experiment designated Unit 7 is scheduled for activation in February, 2002. Other Expedition Four experiments also awaiting activation later in the mission include the Advanced Astroculture plant growth, the Zeolite Crystal Growth and Earth Knowledge Acquired by Middle school students experiments.

Expedition Four's two "sortie" experiments -- Avian Development Facility (ADF) and Commercial Biomedical Testing Module (CBTM) -- were completed during Endeavour's mission to the Station and were returned to waiting scientists when the Shuttle landed on Monday, Dec. 17. ADF studied embryo development, and CBTM studied a potential treatment for osteoporosis.

Crew Earth Observation locations for crew photography for Dec. 16-22 include, industrialized southeastern Africa, Congo-Zimbabwe and Angolan biomass burning, the Nile River Delta, eastern Mediterranean dust and smog, the Tigris-Euphrates river valley, Patagonian and Andean glaciers, the eastern United States, Egypt's Lake Nasser, Lahore, Pakistan, the Parana River area of South America, and the Tuamotu-Austral Islands.

Looking ahead to next week, cell science research will continue on Monday, Dec. 24. After the holiday, on Tuesday, Bursch and Walz are scheduled to complete their Crew Interactions questionnaires. Onufrienko will complete his questionnaire on Thursday, Dec. 27. Also planned that day are the final sessions of the cell science experiment and Pulmonary Function in Flight (PuFF) familiarization for the crew. Bursch and Walz will collect PuFF data on Friday. PuFF focuses on lung function inside the Space Station, as well as during spacewalks. Each PuFF session includes five lung function tests to measure changes in the evenness of gas exchange in the lungs, and on detecting changes in respiratory muscle strength.

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.