Atlantis' rendezvous and docking with the Russian Space Station Mir actually begins with the precisely timed launch of the shuttle on a course for the Mir, and, over the next two days, periodic small engine firings that will gradually bring Atlantis to a point eight nautical miles behind Mir on docking day, the starting point for a final approach to the station.
Mir Rendezvous -- Flight Day 3
About two hours before the scheduled docking time on Flight Day Three of the mission, Atlantis will reach a point about eight nautical miles behind the Mir Space Station and conduct a Terminal Phase Initiation (TI) burn, beginning the final phase of the rendezvous. Atlantis will close the final eight nautical miles to Mir during the next orbit. As Atlantis approaches, the shuttle's rendezvous radar system will begin tracking Mir and providing range and closing rate information to Atlantis. Atlantis' crew also will begin air-to-air communications with the Mir crew using a VHF radio.
As Atlantis reaches close proximity to Mir, the Trajectory Control Sensor, a laser ranging device mounted in the payload bay, will supplement the shuttle's onboard navigation information by supplying additional data on the range and closing rate. As Atlantis closes in on the Mir, the shuttle will have the opportunity for four small successive engine firings to fine-tune its approach using its onboard navigation information. Identical to prior Mir dockings, Atlantis will aim for a point directly below Mir, along the Earth radius vector (R-Bar), an imaginary line drawn between the Mir center of gravity and the center of Earth. Approaching along the R-Bar, from directly underneath the Mir, allows natural forces to assist in braking Atlantis' approach. During this approach, the crew will begin using a handheld laser ranging device to supplement distance and closing rate measurements made by other shuttle navigational equipment.
The manual phase of the rendezvous will begin just as Atlantis reaches a point about a half-mile below Mir. Commander Mike Baker will fly the shuttle using the aft flight deck controls as Atlantis begins moving up toward Mir. Because of the approach from underneath Mir, Baker will have to perform very few braking firings. However, if such firings are required, the shuttle's jets will be used in a mode called "Low-Z," a technique that uses slightly offset jets on Atlantis' nose and tail to slow the spacecraft rather than firing jets pointed directly at Mir. This technique avoids contamination of the space station and its solar arrays by exhaust from the shuttle steering jets.
Using the centerline camera fixed in the center of Atlantis' docking mechanism, Baker will center Atlantis' docking mechanism with the Docking Module mechanism on Mir, continually refining this alignment as he approaches within 300 feet of the station.
At a distance of about 30 feet from docking, Baker will stop Atlantis and stationkeep momentarily to adjust the docking mechanism alignment, if necessary. At that time, a final go or no- go decision to proceed with the docking will be made by flight control teams in both Houston and Moscow.
When Atlantis proceeds with docking, the shuttle crew will use ship-to-ship communications with Mir to inform the Mir crew of the shuttle's status and to keep them informed of major events, including confirmation of contact, capture and the conclusion of damping. Damping, the halt of any relative motion between the two spacecraft after docking, is performed by shock absorber-type springs within the docking device. Mission Specialist Jeff Wisoff will oversee the operation of the Orbiter Docking System from onboard Atlantis.
Undocking, Separation and Mir Fly-Around
Once Atlantis is ready to undock from Mir, the initial separation will be performed by springs that will gently push the shuttle away from the docking module. Both the Mir and Atlantis will be in a mode called "free drift" during the undocking, a mode that has the steering jets of each spacecraft shut off to avoid any inadvertent firings.
Once the docking mechanism's springs have pushed Atlantis away to a distance of about two feet from Mir, where the docking devices will be clear of one another, Atlantis' steering jets will be turned back on and fired in the Low-Z mode to begin slowly moving away from Mir.
Atlantis will continue away from Mir to a distance of about 600 feet, where Pilot Brent Jett will begin a flyaround of the station. Atlantis will circle Mir twice before firing its jets again to depart the vicinity of the station.
The NASA/Mir program is now into the Phase 1B portion, which consists of nine Shuttle-Mir dockings and seven long-duration flights of U.S. astronauts aboard the Russian space station between early 1996 and late 1998. The U.S. astronauts will launch and land on a Shuttle and serve as a Mir crewmember for flight durations ranging from 127 to 158 days, while the Mir cosmonauts stay approximately 180 days and use their traditional Soyuz vehicle for launch and landing. This series of missions will expand U.S. research on Mir by providing resupply materials for experiments to be performed aboard Mir as well as returning experimental samples and data to Earth.
The Mir 22 mission began when the crew launched on August 17, 1996, in a Soyuz vehicle and docked with the Mir two days later. John Blaha joined the Mir 22 crew with the September 19, 1996, docking of STS-79. The return of STS-81 will conclude a mission of experiments in the fields of advanced technology, Earth sciences, fundamental biology, human life sciences, microgravity, and space sciences, as well as send up new research experiments in these areas. Data gained from the mission will supply insight for the planning and development of the International Space Station, Earth-based sciences of human and biological processes, and the advancement of commercial technology.
As scientists learn more about the effects of the space environment, they continue to develop questions from the fields of human life sciences, behavioral sciences, fundamental biology, biotechnology, material sciences, and spacecraft structural and environmental dynamics. Valuable scientific information regarding these subjects will be returned from the Shuttle Mir Science Program disciplines of advanced technology, Earth sciences, fundamental biology, human life sciences, International Space Station, microgravity and space sciences. These investigations will provide valuable information about space flight and long term exposure to the microgravity environment. This knowledge will assist researchers in developing future space stations, science programs, procedures for those facilities, and advance the knowledge base of these areas to the benefit of all people on Earth.
The commercial initiated research and technology from the advanced technology discipline will evaluate new technologies and techniques using the Mir space station as a test bed. An increased understanding of the characteristics of superconductors, protein crystal growth, and the development of biological and chemical systems through fluid processing in reduced gravity can lead to an enhanced technological base for implementation on the International Space Station and commercial processing here on Earth.
Earth sciences research in ocean biochemistry, land surface hydrology, meteorology, and atmospheric physics and chemistry also will be performed. Observation and documentation of transient natural and human-induced changes will be accomplished with the use of passive microwave radiometers, a visible region spectrometer, a side-looking radar, and hand-held photography. Earth orbit will allow for documentation of atmospheric conditions, ecological and unpredictable events, and seasonal changes over long time periods.
Fundamental biology research continues developmental investigations that study the effects of the space environment on the biological systems of plants. Prolonged exposure to microgravity provides an ideal opportunity to determine the role gravity has on cell regulation and how this affects development and growth. Investigations under this discipline will also characterize the internal radiation environment of the Mir space station.
Human life sciences research consists of investigations that focus on the crewmember's adaptation to weightlessness in terms of skeletal muscle and bone changes, psychological interactions, immune system function, and metabolism. In addition, environmental factors such as water quality, air quality, surface assessment for microbes, and crew microbiology will be assessed. These ambitious investigations will continue the characterization of the integrated human responses to a prolonged presence in space.
The International Space Station risk mitigation discipline consists of several technology demonstrations associated with human factors and maintenance of crew health and safety aboard the space station. In order to improve the design and operation of the International Space Station, information is gathered to fully evaluate the Mir interior and exterior environments. This discipline includes investigations of radio interference, crew force impacts to structures, particle impact on the station, docked configuration stability, water microbiological monitoring and inventory management.
Microgravity research will advance scientific understanding through research in biotechnology, fluid physics, combustion science, and materials science. The ambient acceleration and vibration environment of Mir will be characterized to support future research programs.
Space science research continues with the externally mounted Mir Sample Return Experiment (MSRE) and Particle Impact Experiment (PIE) payloads. These experiments continue to collect interstellar and interplanetary space particles to further our understanding of the origin and evolution of planetary systems and life on Earth.
Most of the Mir 22/NASA research will be conducted on the Mir; however, Shuttle-based experiments are conducted in the middeck and modules of STS-81.
The microgravity environment on a long duration mission provides an ideal opportunity to determine the role gravity plays in molecular mechanisms at a cellular level and in regulatory and sensory mechanisms, and how this affects development and fundamental biological growth. Fundamental biology is also responsible for characterizing the radiation of the Mir environment and determining how it may impact station-based science.
Environmental Radiation Measurements: Exposure of crew, equipment, and experiments to the ambient space radiation environment in low Earth orbit poses one of the most significant problems to long term space habitation. As part of the collaborative NASA/Mir Science program, a series of measurements is being compiled of the ionizing radiation levels aboard Mir. During the mission, radiation will be measured in six separate locations throughout the Mir using a variety of passive radiation detectors. This experiment will continue on later missions, where measurements will be used to map the ionizing radiation environment of Mir. These measurements will yield detailed information on spacecraft shielding in the 51.6-degree-orbit of the Mir. Comparisons will be made with predictions from space environment and radiation transport models.
Greenhouse-Integrated Plant Experiments: The microgravity environment of the Mir space station provides researchers an outstanding opportunity to study the effects of gravity on plants, specifically dwarf wheat. The greenhouse experiment determines the effects of space flight on plant growth, reproduction, metabolism, and production. By studying the chemical, biochemical, and structural changes in plant tissues, researchers hope to understand how processes such as photosynthesis, respiration, transpiration, stomatal conductance, and water use are affected by the space station environment. This study is an important area of research, due to the fact that plants could eventually be a major contributor to life support systems for space flight. Plants produce oxygen and food, while eliminating carbon dioxide and excess humidity from the environment. These functions are vital for sustaining life in a closed environment such as the Mir or the International Space Station.
Wheat is planted and grown in the "Svet," a Russian/Slovakian developed plant growth facility, where photosynthesis, transpiration, and the physiological state of the plants are monitored. The plants are observed daily, and photographs and video images are taken. Samples are also collected at certain developmental stages, fixed or dried, and returned to Earth for analysis.
Human Life Sciences: The task of safely keeping men and women in space for long durations, whether they are doing research in Earth orbit or exploring other planets in our solar system, requires continued improvement in our understanding of the effects of space flight factors on the ways humans live and work. The Human Life Sciences (HLS) project has a set of investigations planned for the Mir 23/NASA 4 mission to determine how the body adapts to weightlessness and other space flight factors, including the psychological and microbiological aspects of a confined environment and how they readapt to Earth's gravitational forces. The results of these investigations will guide the development of ways to minimize any negative effects so that crewmembers can remain healthy and efficient during long flights, as well as after their return to Earth.
Assessment of Humoral Immune Function During Long Duration Space Flight: Experiments concerned with the effects of space flight on the human immune system are important to protect the health of long duration crews. The human immune system involves both humoral (blood-borne) and cell-mediated responses to foreign substances known as antigens. Humoral responses include the production of antibodies, which can be measured in samples of saliva and serum (blood component). The cell-mediated response, which involves specialized white blood cells, appears to be suppressed during long duration space missions. Preflight, baseline saliva and blood sample are collected. While on Mir, the crew is administered a subcutaneous antigen injection. In flight and postflight, follow-up blood and saliva samples are collected to measure the white blood cell activation response to the antigen.
Diffusion-Controlled Crystallization Apparatus for Microgravity --Protein crystals are used in basic biological research, pharmacology and drug development. Earth's gravity affects the purity and structural integrity of crystals. The low gravity environment in space allows for the growth of larger, purer crystals of greater structural integrity. Therefore, the analyses of some protein crystals grown in space have revealed more about a protein's molecular structure than crystals grown on Earth. During STS-81, astronauts will retrieve protein samples that have been growing on Mir since the STS-79 docking on September 19 and replace them with new samples.
In the experiment chamber called the Diffusion-controlled Crystallization Apparatus for Microgravity (DCAM), crew members will remove the "growing" samples and replace them with 162 new samples. The DCAM is designed to grow protein crystals in a microgravity environment. It uses the liquid/liquid and dialysis methods in which a precipitant solution diffuses into a bulk solution. In the DCAM, a "button" covered by a semi-permeable membrane holds a small protein sample but allows the precipitant solution to pass into the protein solution to initiate the crystallization process. The DCAM is a method to passively control the crystallization process over extended periods of time. The Principal Investigator is Dr. Daniel Carter of Marshall Space Flight Center in Huntsville, AL.
Gaseous Nitrogen Dewar -- Frozen protein samples will be transported to the Russian Mir space station in a gaseous nitrogen Dewar (GN2 Dewar) on STS-81, and the existing protein crystals on board Mir from the STS-79 mission will be returned to Earth for laboratory analysis. The Dewar is a vacuum jacketed container with an absorbent inner liner saturated with liquid nitrogen. The protein samples will remain frozen for approximately two weeks, until the liquid nitrogen has completely boiled off. This provides ample time to transport and transfer the Dewar to the Mir station. After the liquid nitrogen is completely discharged, the samples will thaw to ambient temperature and protein crystals will nucleate and start growing over the four-month duration of the mission. The Principal Investigator is Alex McPherson of the University of California - Riverside.
Liquid Metal Diffusion (LMD) using MIM--The LMD experiment will measure the diffusion rate of molten indium at approximately 392 F. Diffusion is the process by which individual atoms or molecules move as a result of random collisions with neighboring atoms and molecules. Diffusion is difficult to study on Earth because gravity masks the effect of the collisions, that is, hot pockets of liquid rise while the more dense, cooler areas sink. Radiation detectors in the LMD hardware will measure the diffusive motions of a radioactive tracer in non-radioactive indium. The Microgravity Isolation Mount (MIM) will be used to isolate the experiment from vibrations which could disturb the liquid indium during the experiment and induce motions which are not diffusive. The MIM will also be used to provide measured vibrations for some samples to determine how easily diffusion can be affected by these forces. A total of five samples will be processed. The information obtained from diffusion measurements can be used to determine the rate at which material travels between two bodies of fluids separated by a stagnant layer which the material must diffuse through. This is a common occurrence for some types of crystal growth and alloy processing on Earth. The Principal Investigator is Dr. Franz Rosenberger of the University of Alabama - Huntsville.
Optical Properties Monitor (OPM)-- OPM is the first experiment capable of relaying on-orbit data which will measure the effect of the space environment on optical properties, such as those of mirrors used in telescopes, and structural elements, such as the coatings used on space hardware. OPM instruments will measure various optical properties of the, overall showing to what extent the samples deteriorate over the course of the experiment.
Once aboard Mir, American astronauts and Russian cosmonauts will mount the monitor to the outside of the space station. This marks the first experiment deployed jointly by the U.S. and Russia, setting the stage for how the astronauts and cosmonauts will work together on the International Space Station.
During its scheduled nine months on Mir, the experiment will measure the environment's effect on nearly 100 sample materials. The monitor will be the first externally powered experiment in space, using a power-data line to receive power from and transmit information to the Mir. The monitor will collect and store measurements to be transferred weekly to a Mir computer, then to scientists on Earth.
Information gathered will be used to improve designs of optical and structural elements of spacecraft, particularly the International Space Station. It will also be used to plan maintenance schedules for in-orbit satellites, based on measured rates of degradation.
OPM was developed by NASA's Marshall Space Flight Center and AZ Technology of Huntsville, AL. It is scheduled to be retrieved from Mir in February 1998 during the STS-89 mission. The Principal Investigator is Donald Wilkes of AZ Technology in Huntsville, AL.
KIDSAT TO FLY AGAIN ON SPACE SHUTTLE
The electric still cameras aboard the Space Shuttle Atlantis will support the second flight of KidSat, as part of NASA's three- year pilot education program designed to bring the frontiers of space exploration to 15 U.S. middle school classrooms via the Internet during the STS-81 mission.
The pilot program is a partnership between NASA's Jet Propulsion Laboratory (JPL), the University of California at San Diego (UCSD), and the Johns Hopkins University Institute for the Academic Advancement of Youth (JHU-IAAY).
During the Shuttle flight, the KidSat mission operations center at UCSD will be staffed by undergraduate and high school students. The center has capabilities similar to those of Mission Control at NASA's Johnson Space Center (JSC) in Houston. The students receive telemetry from the Shuttle on their computer monitors and can listen to and receive instructions from NASA's flight controllers over direct channels to JSC.
The KIDSAT mission operations team monitors the Shuttle's progress around the clock and continually provides up-to-date information to the middle schools, who are using the Internet to send instructions to photograph specific regions of the Earth. Since any change in the Shuttle's orbit can affect students' selections, UCSD constantly updates this information so that the middle schools may re-plan their photograph requests if necessary. This is done through a sophisticated web site that allows middle school students access to interactive maps of orbit ground tracks and other resources to aid in photo selection.
When the image requests have been verified by KidSat mission operations, they are compiled into a single camera control file and forwarded electronically to the KidSat representatives at JSC. They pass this file on to flight controllers who uplink it to an IBM Thinkpad connected to the KidSat camera. Software on the thinkpad, developed by students working at JPL, uses these commands to control the camera. These same students trained the astronauts on the use of the software and the installation of the KidSat camera in the Shuttle's overhead window.
After the photographs are taken, they are sent back down to the KidSat Data System at JPL, staffed by high school students during the mission, and posted on the world wide web for the middle school students to study and analyze. The curriculum used by the middle school students and teachers was developed by the JHU-IAAY and UCSD. Teachers participating in the mission learn to use the curriculum during summer training workshops.
Some of the topics the students were interested in exploring during the first KidSat mission were weather, biomes, the relationship between history and geography and the patterns of rivers on the landscape. Additional interests for this mission include searching for impact craters and studying the relationships of center pivot irrigation fields to available water supply.
Images and student results will be posted on the KidSat home page. Interested public school districts, teachers, and students may view the images and information provided by students during the mission via this World Wide Web site: http://www.jpl.nasa.gov/kidsat
The KidSat pilot program is sponsored by NASA's Office of Human Resources and Education, with support from the Offices of Space Flight, Mission to Planet Earth, and Space Science.