STS-89 will carry five science payloads from NASA/Marshall
STS-89 will carry five science payloads from NASA/Marshall Â
January 16, 1998: STS-89 will carry five NASA/Marshall science payloads, two for an extended stay aboard Russia's Mir space station, two for a return from Mir, and one for operations in the Spacehab module during the mission.
Joel Kearns, manager of NASA's Microgravity Research Program Office, said that the STS-89 mission will continue NASA's science program aboard Mir.
Building blocks for Earth
One payload continues an exciting series of experiments into the behavior of soil under conditions that cannot be simulated on Earth, but which affect how the ground behaves during earthquakes or how powders are handled during the manufacture of drugs, cosmetics, and other products. The Mechanics of Granular Materials (MGM) experiment first flew on the STS-79 mission in 1996. On STS-89, it will make twice as many test runs under an expanded range of conditions. It compresses a column of sand contained in a latex sleeve within a water-filled plastic case (right).
"MGM is a very interesting science experiment that may have great ramifications for down-to-Earth engineering in the future," Kearns said. "We know, through science studies going back 50 or 60 years, that under certain conditions - such as shock waves produced during an earthquake or the collapse of a grain silo - that what looks like a gigantic mass of solidly packed-together materials - like sand or grain or agricultural products in a process conveyor belt - will suddenly behave as if they were a flowing liquid, not like a solid mass at all."
One of the "surprising findings" from the experiment on STS-79 is that even under destabilizing conditions, granular materials are as much as 80 percent more stable than once expected.
"The granular materials in a situation such as that may remain stable for up to 10 to 20 seconds during the onset of the earthquake," Kearns said., "But under the more prolonged shaking that takes place in an extended tremor, they would begin to lose stability and slide with respect to each other."
Building blocks of life
The other four payloads support work by NASA/Marshall and the biomedical community to determine the structure and function of the thousands of proteins used in the human body and in valuable plants and animals. The Diffusion-controlled Crystallization Apparatus for Microgravity (DCAM) and the Protein crystal growth nitrogen Dewar (right) will be placed aboard Mir where they will slowly grow crystals of various proteins over the next few months until retrieval by the STS-91 mission in May. These two experiments operate without direct crew involvement.
Dr. Daniel Carter of New Century Pharmaceuticals, principal investigator for DCAM, described two significant advances with such experiments. In one case, scientists have grown crystals of HIV protease inhibitor that are significantly larger and of higher quality than any previous specimens. This will help in defining the structure of the protein which is important in fighting the AIDS virus.
Another team, which includes Carter, has been able to define the structure of the recombinant antibody that fights respiratory synctial virus (RSV), the most serious infectious disease that affects infants in the United States. More than 4 million cases a year are reported, with more than 4,000 infants dying from it. The active region of the antibody has been defined, which will help scientists to develop smaller, more easily made molecules that have the same therapeutic effect.
"If these two examples could be referred to as gems," Carter said, "this next one is really a crown jewel." He showed pictures (right) of pike parvalbumin, a protein found in a type of fish egg. Samples grown one two Space Shuttle flights in 1997 showed extraordinarily high resolution when scanned by X-rays, a standard method for studying the structures of crystals. Carter said the detail was the best yet for so large a protein (more than 200 amino acids in size), and will also allow the first protein crystal studies by even finer neutron diffraction.
Returning on STS-89 will be the Interferometer Protein Crystal Growth Apparatus (IPCG), a device placed aboard Mir by the STS-86 mission. IPCG uses a compact optical system to show how the concentrations vary inside a solution as a protein crystal grows in the microgravity environment of space. The system was operated by astronaut David Wolf (left) and provides video images captured on computer. An improved understanding of how large protein molecules move through a liquid will help scientists in tailoring techniques for growing large, near-perfect crystals in space for analysis on the ground.
IPCG was set up and operated inside the Middeck Glovebox facility that was installed aboard Mir in April 1996. The STS-89 mission will return the glovebox to Earth for detailed examination to help determine the long-term effects of space operations on experiment hardware. The glovebox supported a range of microgravity science experiments in addition to IPCG.
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