10 February 2003
Scientists Seek to Learn How Much Research Data Lost with Columbia
(Shuttle carried science experiments from around the world) (1110) By James Fuller Washington File Science Writer Washington -- The space shuttle Columbia - its 16-day mission devoted entirely to science - carried more than 80 experiments sponsored by space agencies, universities and organizations from around the world. Researchers are now working to determine exactly how much research data was lost on February 1 when Columbia broke up high above the Earth as it descended for a landing at Kennedy Space Center in Florida. Fortunately, some of the scientific data collected by Columbia's seven-astronaut crew was downlinked to researchers on Earth during the mission. The experiments aboard Columbia - most contained within a new SPACEHAB pressurized research laboratory carried in the shuttle's cargo bay - included a study on fire suppression from the Colorado School of Mines, studies on combustion engines from the University of Southern California, research on bone growth in microgravity by a team of Canadian institutions, and a study of the impact of dust clouds on global warming from Tel Aviv University - the experiment overseen on the shuttle by Ilan Ramon, Israel's first astronaut. There were also biological investigations sponsored by the European Space Agency that examined the cardiopulmonary changes occurring in astronauts during space flight, and others examining bone formation, immune system functioning, and connective tissue growth and repair. The German Space Agency sponsored experiments that measured the development of the gravity-sensing organs of fish in the absence of gravity's effects, while the U.S. Air Force conducted a communications experiment. There were even experiments organized by elementary school students in Australia, China, Israel, Japan, Liechtenstein and the United States probing the effects of space flight on fish, spiders, ants, silkworms, bees and inorganic crystals. Microgravity has become a powerful tool for studying the inner workings of flames, the behavior of human cells and other phenomena. On Earth these studies run into limitations imposed by the effects of gravity. The term microgravity refers to the fact that those on a spacecraft orbiting the planet experience from one-thousandth to one-millionth of Earth's normal gravitational pull as they freefall around the globe. "There are many aspects of space we can't mimic on Earth," said John Charles, a shuttle mission scientist at the Johnson Space Center in Houston. "We can turn down air pressure in laboratory vacuum chambers and bombard samples with space-like radiation. We can't turn off gravity, though, or look down on Earth from above. Space is a truly alien environment. Many things behave differently up there." A good example was the flame experiments conducted aboard Columbia. Unlike flames on Earth, which have a tear drop shape caused by air rising in a gravitational field, flames in space break apart into floating spheres a few millimeters in diameter. Each of these flame balls, created in a chamber about the size of an office trash can filled with combustible gases, produces one to two watts of thermal power - much less than a 50-watt birthday candle. They burn using almost no fuel, something researchers would like to replicate in gas-saving auto engines. According to data sent back to Earth from Columbia, the shuttle astronauts created and observed the weakest flames ever created - which were as small as 2 millimeters across. The astronauts aboard Columbia also tested a new commercial fire-fighting system that puts out blazes with a fine water mist - instead of using harmful chemicals or large quantities of water that damage property. The shuttle tests used a humidifier-like device to produce water drops about 20 microns in size - about 50 times smaller than the drops produced by conventional sprinklers. Also, in microgravity, air currents are reduced or eliminated, making it easier for scientists to observe exactly how water interacts with a flame to put it out. Until recently, bromine-based compounds called halons were used to attack fires chemically - especially in places like computer and document storage rooms. In 1998, the production of these chemicals was banned worldwide because they damage the Earth's protective ozone layer. "We are working to find an acceptable replacement for halons, and water mist appears to be the best choice," said Thomas McKinnon, lead scientist for the water mist research project at the Colorado School of Mines in Golden. Another experiment aboard Columbia compressed granular materials to get a better understanding of construction techniques that may provide stronger foundations for structures in areas where earthquakes, floods and landslides are common. When an earthquake strikes, wet soil underground sometimes "liquefies." This happened during the 1989 Loma Prieta earthquake in San Francisco, when vibrations liquefied the water-soaked soil in the Marina District of the city, causing buildings to sink until their third floors were at ground level. This transition to liquefaction is rapid and poorly understood. Stein Sture, a professor of engineering at the University of Colorado in Boulder, says studying the liquefaction process with sand in ground-based laboratories is difficult because the sand's own weight creates stress on the grains. However, he says experimenters in space could remove that stress and more easily probe soil liquefaction. "Understanding this soil liquefaction process will help engineers decide when a site is safe for construction, and perhaps lead to designs for building foundations that help prevent liquefaction from occurring," Sture said. Columbia also carried many experiments involving biology and biotechnology. Several studies, for example, grew protein crystals more purely and with fewer flaws than is possible on Earth. One such protein crystal-growing experiment was studying possible therapies against factors that cause cancers to spread, and another was aimed at the development of a new technique for encapsulating anti-cancer drugs to improve their efficiency. A rotating bioreactor aboard Columbia suspended and nurtured cells for three-dimensional tissue growth under conditions impossible to replicate on Earth. One such experiment on prostate cancer documented greater-than-expected growth of tumor cells in space. Other studies aboard Columbia were aimed at finding out how viruses spread and are shared within closed environments. Some scientists have long maintained that the caliber of the science being performed aboard the shuttle and the space station did not justify the costs of manned spaceflights. Now, with the world still grieving over the deaths of the seven Columbia astronauts, some expect that argument to intensify. However, officials of the National Aeronautics and Space Administration (NASA) argue that if even one space-based experiment eventually results in a new therapy, or cleaner engines, or some other benefit, then the investment in space research will be recouped many times over. (The Washington File is a product of the Office of International Information Programs, U.S. Department of State. Web site: http://usinfo.state.gov)
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