ISS Expedition Two Science Operations Weekly Science Status Report Thursday, July 12, 2001
A group of excited middle and high school student scientists watched at NASA’s
Kennedy Space Center today as an experiment they helped prepare was launched
aboard Space Shuttle Atlantis to the International Space Station.
Students from Alabama, California and Tennessee mixed and loaded about 100
of the 500 biological samples in small plastic tubes in the Enhanced Gaseous
Nitrogen Dewar, the last Expedition Two experiment to be launched to the
orbiting laboratory. This is the third trip to the Station for the experiment.
More than 500 schools across the country have participated in the program since
it began in 1999.
The samples contain biological materials that carry out many important functions
in humans, animals and plants. In space, the materials will form crystals that
will be returned to Earth in August by Space Shuttle Discovery.
Scientists will retrieve the samples and analyze them to determine the structure
of the biological molecules. Knowledge of the precise three-dimensional molecular
structure is an important tool for biochemists designing medicines. Students
in this pilot hands-on program can monitor the results on a special Web site.
The Dewar experiment and the student experiment program are sponsored by the
Microgravity Research Program Office at NASA’s Marshall Space Flight Center
in Huntsville and the Office of Biological and Physical Research at NASA Headquarters
in Washington, D.C., with support from several educational and corporate institutions.
Aboard the Station, an experiment that could stimulate a new field of engineering
and lead to new materials and products ranging from food to lasers just completed
its third and most successful week of operations aboard the International Space
Station.
The Experiment on the Physics of Colloids in Space (EXPPCS) may contribute
to decreased product development time and more efficient manufacturing. A colloid
is a system of fine particles suspended in a fluid. Paint, milk and ink are
common examples.
Though these products are routinely produced and used, scientists have much
to learn about their underlying properties. New information about the structure
of colloids may further develop the field of colloid engineering. This research
could lead to materials for optical switches and lasers for advanced communications
and displays. Industries using semiconductors, electro-optics, ceramics and
composites are among those that may benefit from this research. The experiment
also may help improve colloidal properties in common materials, including food,
paints, and coatings.
A 48-hour diagnostic run, which began on Thursday, July 5, was followed by
additional 12-hour experiment runs on Sunday and Tuesday, July 8 and 10. These
tests were continuations of a survey of crystal nucleation and growth initiated
in late June and designed to determine the crystallization time and other characteristics
of the samples and re-verify and optimize diagnostic techniques used to measure
the crystallization activity of each sample.
Once a sample is melted, a laser beam illuminates the sample to enable images
of scattered light to be taken, and then a pair of color cameras snap a series
of pictures at two magnifications to capture information about the arrangement
of individual particles as well as the larger structures formed.
ìThis past weekend things flowed along very well with the whole operation,î
EXPPCS Project Manager Michael Doherty of NASA’s Glenn Research Center in Cleveland
said. ìThis was the first experiment run where we were able to complete the
full scope of diagnostics requested by the principal investigator teams. Our
team is getting the hang of how to do this stuff and take advantage of the Ku
(communications) band windows.î
The colloids experiment is expected to remain on the station for a year with
colloid samples being re-melted and re-formed numerous times.
Testing and checkout activities ó continue with the Active Rack Isolation
System ISS Characterization Experiment (ARIS-ICE). It is designed to precisely
test the ability of the ARIS dampening device to protect delicate microgravity
experiments from vibrations caused by astronauts, powered equipment or docked
spacecraft.
The hardware is located in EXPRESS Rack 2 in the Destiny lab module. Tests
over the weekend indicated that one the eight actuators ó essentially powered
shock absorbers ó that provide a reactive force to unwanted vibrations was sticking
in the same position. Flight Engineer Jim Voss on Monday inspected the rack
for interferences that could cause the problem. After Voss removed or moved
some possible obstructions, results from tests conducted by ground controllers
indicated the actuator problem was not solved, and they asked Voss to replace
it with a spare onboard. The procedure is still being planned.
One of the most important tests of the vibration dampening system will occur
during docked operations with Space Shuttle Atlantis.
ìThe greater the mass of the Station, the more low frequency disturbances you
have,î said James Allen, ARIS-ICE project lead and payload developer.
Scientists plan to go ahead with ARIS tests using only seven of the eight
actuators in the rack. It was designed to operate with two actuators out, and
seven-actuator operation was one of the original tests planned for docked operations.
Once the eighth actuator is replaced, scientists will look for another opportunity
to test it during a later spacecraft docked period.
The list of targets uplinked to the Station for the Crew Earth Observations
photography research effort this week includes the Ganges River Delta wetlands
and population centers, manmade lakes in the Tigris-Euphrates river area of
Turkey, the Rukwa Transform fault zone in Tanzania, and snow cover in the Canadian
Rockies.
Automated experiments aboard the station continued to operate normally, monitored
by controllers and science teams on the ground. The crew continues to conduct
normal maintenance of active science experiments — re-charging radiation
sensors, downloading sensor data to computers, checking experiment status displays.
Controllers continue to downlink data from the Station and distribute it to
scientists around the country and plan for the start of Expedition 3 Station
mission.
At the Payload Operations Center in Huntsville, the Expedition 3 day shift
control team began work on console this week. The entire cadre will begin round
the clock operations July 23 and move from the backup control room to the main
control room in order to be ready to support the scheduled August 9 launch of
the STS-105 Shuttle mission that will carry the Expedition Three crew to the
Station and return the Expedition Two crew.
