ISS Science Operations Weekly Status Report 17 Jan 2002
The Expedition Four crew wrapped up its orbital construction duties this
week with a science experiment to measure how well the crew’s lungs function
following exposure to the low pressure environment of their spacesuits
as well as exposure to the confined atmosphere of the Space Station.
Following his spacewalk on Monday, Jan. 14, Flight Engineer Carl Walz
performed a post-EVA session Tuesday with the Pulmonary Function in
Flight (PuFF) experiment. Flight Engineer Dan Bursch also volunteered
to perform the test, and the science team was enthusiastic to get the
additional data. Following an EVA on Jan. 25 involving Bursch, he and
Walz are scheduled to perform another PuFF session on Jan. 26, which will
serve as Bursch’s post-EVA test and Walz’ monthly test.
PuFF, developed by the University of California, San Diego and managed
by NASA’s Johnson Space Center, focuses on lung function both following
EVA and inside the station during long-term exposure to microgravity,
laying the groundwork for future experiments key to understanding and
maintaining crew health.
Spacewalkers can suffer decompression sickness just as scuba divers do
when they come to the surface too quickly. Decompression sickness results
from exposure to low barometric pressures that cause inert gases – mainly
nitrogen – that are normally dissolved in body fluids and tissues to form
bubbles. Symptoms can include headaches, memory loss and blurred vision.
EVAs pose a risk of nitrogen bubble formation because spacesuits operate
at 4.3 pounds of pressure instead of the 14.7 pounds found on Earth and
inside the Space Station.
Each PuFF session includes five lung function tests, which involve breathing
only cabin air. The focus is on measuring the evenness of gas exchange
in the lungs and detecting changes in respiratory muscle strength, which
may result from long periods in the absence of gravity.
In addition to benefiting future space explorers, PuFF may contribute
to clinical medicine on Earth because gravity affects the way the lungs
operate and may even exaggerate some lung disorders, such as emphysema
and tuberculosis.
The Active Rack Isolation System ground team on Monday downlinked
data and sent up various file management commands, important steps in
completing ARIS’ performance analysis and freeing up space on the computer
hard drives. Ground commanded isolation tests of the experimental vibration
dampening device continued this week. The first hammer tests by the Expedition
Four crew are planned for next week. A crew member uses a small hammer
to tap on and around the rack to see if ARIS can quiet the vibrations
to EXPRESS Rack 2, where it is housed.
The Experiment on Physics of Colloids successfully completed a
120-hour run last week, the longest test to date by that experiment.
Monday’s 24-hour colloids test was the last prior to initiating the first
fractal gel tests, which will last about five weeks. The Monday test
was run to do some final measurements on the AB6 and glass samples prior
to being unable to examine any sample other than the fractal gels. Colloids,
fine particles suspended in a fluid, are commonly used in many products
and manufacturing processes on Earth. Space experiments may contribute
to development of new materials and other uses for colloids.
Sites uplinked to the Station for the Crew Earth Observations
photography research program this week included wake clouds and von Karmen
vortices in the Canary Islands, fires in the African Sahel, coral reefs
and atolls in the Tuamotu Archipelago, tropical glaciers and ice fields
in New Guinea, air pollutants off the Eastern United States shores, Patagonian
glaciers, damage from Hurricane Juliette in the Cabo San Lucas area of
Baja, California, and manmade lakes westward from the Nile River into
the Egyptian desert.
The crew this week is continuing to participate in the Crew Interactions
experiment on their station laptop computer, and they continue to perform
normal maintenance and status checks on the station’s various automated
science experiments controlled from the ground.
Overall, of the 25 experiments planned for Expedition Four, three are
complete, 15 are in progress now and seven are planned for later in the
Expedition, including four, which will arrive on the upcoming 8A Space
Shuttle mission.
