ISS Expedition Two Science Operations Weekly Science Status Report 28 Jun 2001
An experiment that could make the Space Station an even better place to
conduct microgravity experiments is undergoing tests this week in the
orbiting laboratory.
The Active Rack Isolation System (ARIS) located in EXPRESS Rack 2 in the
Destiny lab module is designed to act like a powered shock absorber to
dampen vibrations from powered equipment and crew activities.
During the past week, the Station crew and controllers and the science team
on the ground began readying the system and a related experiment called the
ARIS ISS Characterization Experiment (ARIS-ICE) that will precisely test and
then measure the performance of the ARIS vibration dampening system.
The crew began setting up the ARIS system on May 29. On Friday, June 22,
they completed setup work for the ARIS-ICE hardware, allowing ground
controllers to send commands to check out the equipment on Monday, June 25.
Those checkouts continued this week. Today, Flight Engineer Jim Voss
tightened a pair of pushrods to make sure the dampener functions correctly.
Using sensors and pushrods, ARIS acts like a sophisticated shock absorber to
provide a reactive force between the payload rack and the lab module,
providing a better low gravity environment for delicate experiments.
“We’re very happy with initial installation and checkout activities,” said
James Allen, ARIS-ICE project lead and payload developer. “We’ve verified
the ARIS control system is stable and doesn’t put the rack into an
oscillation. “We’ll continue checkout tests to get ready for the Space
Shuttle docking, which adds greater mass to the Station and will allow us to
do low frequency testing.”
Flight Engineer Susan Helms conducted additional tests with the
Middeck Active Control Experiment II during the past week. The joint U.S.
Air Force Research Laboratory/Massachusetts Institute of Technology
experiment will provide data on decreasing the effects of vibration in
moving structures in space. This will allow future spacecraft to be
designed with low-cost structures lighter in weight than those currently
used, and still achieve performance requirements by actively decreasing the
effects of vibration. The MACE hardware consists of a platform roughly 60
inches (152 centimeters) long, made of four struts less than 1 inch (2.5
centimeters) in diameter connected to five nodes. It is equipped with
sensors and reaction wheels that control the motion and 20 sensors to
measure motion and vibration. When gimbals on one end create a vibration,
gimbals on the other end should remain steady.
Photography targets uplinked to the Station for the Crew Earth Observations
experiment in the past week included European smog, Saharan dust and
volcanic ash and gasses from the smoldering Mt. Etna volcano; water levels
and smog in the Yellow River area around Beijing, urban smog over the
coastal plain of the Eastern United States; urban development and
agriculture along the Suez Canal: runoff sediment in the Gulf of St.
Lawrence; commercial development in the Yangtze River Delta; Turkish water
diversion projects on the Tigris River; smog and haze in the Appalachians;
and urban development in the Ganges River Basin. The crew may also have a
chance to photograph aurorae during the current period of high solar
activity and gas clouds from the Mayon volcano in the Philippines. Lighting
and the Station’s orbital path have prevented the crew from photographing
flooding in Texas.
Planning is under way to return Protein Crystal Growth Single Thermal
Enclosure System Units 9 and 10 on the STS-104 Shuttle mission, now
scheduled for July 12. The last of six growth cylinders in Unit 10 was
deactivated June 18 as planned. The six growth cylinders in Unit 9 are
expected to be deactivated right after the STS-104 launch. Scheduled for
early return on STS-104 is the Commercial Generic Bioprocessing Apparatus,
which experienced a failure earlier in the mission and is being returned for
analysis.
Also returning is the Advanced Astroculture plant growth experiment, which
has completed full plant growth and seed production. It was originally
scheduled to return on the STS-105 Shuttle mission, which has been delayed.
Ground controllers sent commands Monday, June 25, that will preserve the
seeds. The station crew today began reducing the humidity and increasing
the heat in the growth chamber to further dry out the plants and preserve
the seeds. The ADVASC science team is running an identical experiment on
the ground to determine how long the experiment will require power before
deactivation.
The Microgravity Acceleration Measurement System was reactivated as planned
on Tuesday, June 26 and will be on for the next four weeks to help
characterize the microgravity environment of the Station. The other
microgravity measurement device, the Space Acceleration Measurement System,
continues to actively record data.
Other payloads continuing to operate nominally, include: Commercial Protein
Crystal Growth; Experiment on the Physics of Colloids in Space; and three
radiation monitoring experiments – Bonner Ball Neutron Detector, Phantom
Torso, and Dosimetric Mapping. The crew is also completing weekly
questionnaires as part of the Interactions experiment.
The crew continued to conduct normal maintenance of active science
experiments – re-charging radiation sensors, downloading sensor data to
computers, checking experiment status panels and photographing hardware
setups. Controllers on the ground continued to downlink data from the
Station and distribute it to scientists around the country.
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.
