With three-fourths of the Shuttle-Mir program nearly complete, science investigators and mission managers are preparing for the next phase of cooperative efforts that will lead to the most ambitious peacetime scientific project ever undertaken — the International Space Station.
The next phase of Shuttle-Mir includes more planned science experiments than any previous stay by a U.S. astronaut.
“The importance of this program cannot be overestimated,” said Shuttle-Mir program manager Frank Culbertson. “This is where theory meets reality, where the practical lessons we learn aboard the Mir are already paying large dividends as we prepare to start construction of the Space Station in less than a year.”
The launch of Dr. David Wolf aboard Atlantis next week on the STS-86 mission continues a research program started with Dr. Norm Thagard’s stay on Mir in 1995 and includes 35 scientific studies and technology demonstrations spanning six research disciplines. Wolf’s flight furthers the continuous U.S. presence in space that began with Shannon Lucid on the STS-76 mission in March 1996.
At the start of Wolf’s mission, the total U.S. astronaut time aboard the Mir will be 22 months — with 18 months of continuous occupancy since March 1996.
Wolf’s mission to Mir specifically involves six research disciplines including advanced technology, Earth sciences, fundamental biology, human life sciences, microgravity research and a category for learning the lessons necessary to successfully build the Space Station — the engineers call it “risk mitigation.”
Despite the June 25 collision of a resupply vehicle with the Mir, most of the research for Wolf’s mission will go ahead. The loss of life sciences hardware will be partly offset by the launch of replacement equipment and by new techniques for achieving scientific goals. Following two successful spacewalks, which increased available electricity aboard the Mir, U.S. science operations during Wolf’s mission to Mir are not expected to be limited by power.
The investigations from this mission will add to the growing body of results from the program. To date, approximately 120 U.S. scientific studies have been conducted aboard Mir by researchers from the United States, Russia, Canada, France, Germany, Hungary and Japan. Several significant accomplishments from Shuttle-Mir research are described below.
Of prime importance to the health of crew members and basic research is the monitoring of the Mir’s environment. Given time aboard the Mir, station researchers have learned to better monitor vital factors such as air and water quality and radiation levels. These techniques have been validated and will continue to be used on the Space Station. These studies have shown that the Mir environment is safe for crew members, and in the case of occasional temporary incidents, proper monitoring and adequate protective measures are available.
fƒ-> Studies aboard the Mir have allowed more precise characterization of human physiology and psychology in space, in particular changes in bones and muscles, the neurovestibular system, the risk of developing kidney stones in space, and changes in the interactions among crew members and their ground support team over the course of the mission.
The space flight-induced changes seen in muscles and bones are similar to those seen in bedridden or osteoporotic patients and characterization of these changes in healthy crew members may lead to better methods of rehabilitation and treatment for patients on Earth. The Shuttle-Mir program has allowed NASA to evaluate the effectiveness of the countermeasures that the Russians have developed over the past 25 years to minimize the effects of long-term weightlessness.
New techniques and methods have been used to produce protein crystals and other substances, providing both qualitative and quantitative improvements over ground-based and previous space-
based experiments. The long-duration nature of this program has allowed researchers to produce some crystals that cannot be grown on the Shuttle or on Earth. Analysis of the higher quality crystals grown on Mir permits better understanding of their molecular structure, leading to better understanding of viral interactions with antibodies, enzyme functions, and possibly new pharmaceutical products.
Aboard a space station, microgravity experiments are especially sensitive to vibration. A study using new sensors has measured vibration levels of normal work routines and how that may affect experiment processing. The study, begun in 1996 by Shannon Lucid aboard Mir, has measured much lower vibrations on Mir compared with data obtained during the U.S. Skylab program of the 1970s. This information is directly beneficial to the Space Station Program where it is being used to assess the potential impact of crew motion on the microgravity environment.
The promise of tissue culturing in space has been dramatically advanced by work aboard the Mir. NASA was able to extend the duration of space tissue growth from 10 days to four months, with the successful culturing of cartilage cells in an onboard bioreactor. Wolf was a member of the research team that originally developed the bioreactor design at the Johnson Space Center, Houston, TX.
On Earth, tissue culturing is largely limited to two dimensions. In the space flight experiment, the tissue grew in a three-dimensional structure more like tissue in a living organism would grow. In addition to the scientific result of the experiment, NASA learned how to upgrade the facility for future use on Mir as well as on the Space Station.
Growing plants in space is of scientific interest for botanists and future space flight operations. A significant first in this area has been achieved during the Shuttle-Mir program when seeds generated by plants grown in space were planted and germinated to grow new plants — the first so-called “seed-to-
seed” experiment in space. This is a significant development in the ability to grow plants in space and was achieved after the Spektr collision during the low-power period on Mir.
Russian, Canadian and U.S. facilities aboard Mir have been used to perform experiments in fluid physics, combustion science, colloid science, metallurgy and diffusion of liquids such as metals heated in a furnace. The facilities included furnaces, a glovebox to contain experiments as required, and a system to isolate experiments from the station’s vibration environment. Some experiments tested, verified or modified basic theories in fluid physics.
The controlled combustion experiments provided a better understanding of how flames spread in space. Colloids, solid particles suspended in liquid, are seen in every day life as cosmetics, paints and other industrial products, and their study in weightlessness without the disturbing influence of gravity can lead to better commercial products here on Earth.
The astronauts on Mir have substantially added to the growing database (about 300,000 images) of Earth observation photographs. During their months aboard the Mir, crew members have observed and recorded long-term and seasonal changes in various areas of interest. Agricultural patterns, global deforestation and drying up of lakes can be monitored over long periods of time. In addition, astronauts have observed and photographed rapidly occurring events such as volcanic eruptions and fires that otherwise may have gone unobserved.
New findings about the South Atlantic Anomaly’s northwestward migration have been published based on results from Mir, and a better understanding of the solar cycle has been made possible.
Investigators preparing for the International Space Station program have learned a great deal from experiments monitoring the external environment of Mir which, in many cases, will be similar to the external conditions around the Space Station. Sensors placed on the outside of Mir have detected everything from micrometeoroids to leftover specks from spent rocket stages. The data also show that large detectable pieces of orbital debris in some cases may be accompanied by clouds of particles too small to detect, but that may also cause deterioration of solar panels and other external structures.
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