ISS Weekly Science Status Report 25 Oct 2001
An experimental “powered shock absorber” to reduce
vibrations aboard the Space Station continued another week of
intensive testing to get ready for its operational debut next year.
The Active Rack Isolation System (ARIS) uses actuators that act like
powered shock absorbers to counter vibrations caused by crew
activities, operating equipment and other disturbances. Installed in
EXPRESS Rack 2 in the Destiny lab module, it is designed to protect
delicate microgravity experiments from vibrations that could
negatively affect them. The first experiment to benefit from the ARIS
system will be Zeolite Crystal Growth, scheduled to begin operations
in March 2002.
The ARIS ISS Characterization Experiment (ARIS-ICE) was developed to
test the ARIS system. Recent tests have focused on understanding how
a pair of cables going into the EXPRESS Rack affects the vibration
dampening qualities. Cable materials, thickness, length, and position
can all affect vibration. Of particular interest is a set of newly
developed experimental “vibration-free” cables that appear
to be 200-300 percent less stiff than the original cables.
“The cables connect the Station Z panel, a power and utility
interface panel, and the ARIS rack to provide power,” said
Naveed Quraishi, ARIS-ICE project manager at NASA’s Johnson
Space Center. “The majority of vibration to the rack comes from
the Z panel through the umbilicals into the rack. We have so far
successfully characterized the performance of ARIS from .01 to 1 hertz
and from 30 hz to 300 hz. Now we’re working on the 1-30 hz
regime. We are in a very aggressive testing mode until the end of the
expedition. The new cables have improved performance quite a
bit.”
ARIS-ICE is scheduled for return to Earth next year, but it could
offer advantages in making the checkout of future ARIS-equipped racks
simpler and more efficient, Quraishi said.
The Experiment on Physics of Colloids in Space (EXPPCS) completed a
48-hour test run on Monday, October 22. Like most of the runs in the
past two weeks, it continued to examine the colloid polymer gel and
colloid glass samples. Colloids are found in many everyday products on
Earth, like paint and milk, and are used in many other manufacturing
processes ranging from foods to computer chips. This basic research,
managed by NASA’s Glenn Research Center, could contribute to
engineering of new materials and processes.
The Station’s main vibration measuring experiments, the Space
Acceleration Measurement System and the Microgravity Acceleration
Measurement System (MAMS), recorded Tuesday’s docking of a Soyuz
taxi craft and the arrival of three new cosmonauts aboard the Station.
The science team now has recorded several events such as Shuttle,
Soyuz and Progress spacecraft dockings, a Soyuz re-location, and
spacewalks for building a better picture of the microgravity
environment on the Station.
The NASA payload team this week was preparing to downlink some
experiment results recorded during earlier experiments with the
Dynamically Controlled Protein Crystal Growth, MAMS, Bonner Ball
Neutron Detector, and Hoffman Reflex.
Targets uplinked for the Crew Earth Observations photography program
this week included: land use patterns along the Parana River in
Argentina, stream patterns and sand dunes along the Somalia coast,
flood waters from the Aswan Dam on the Nile River, reef damage in the
Tuamotu Archapelago, smog in the Ohio River basin and the northeast
U.S., vegetation color signatures in California’s Central
Valley, fault lines in Ethiopia, and new dams along the Euphrates
River in Turkey.
On Wednesday, October 24, the Station crew and controllers in the
Payload Operations Center teamed up to successfully install a computer
software upgrade in EXPRESS Rack 4. The upgrade is designed to
prevent software problems observed with EXPRESS Racks 1 and 2, which
received a similar upgrade.
Editor’s Note: The Payload Operations Center at NASA’s
Marshall Space Flight Center in Huntsville, Ala., manages all science
research experiment operations aboard the International Space Station.
The center is also home for coordination of the mission-planning work
of a variety of international sources, all science payload deliveries
and retrieval, and payload training and payload safety programs for
the Station crew and all ground personnel.
