ISS Science Operations Status 3 Apr 2002
A trio of Space Station experiments this week are zeroing in on the sources
of vibrations that could disturb future delicate microgravity experiments.
Three Active Rack Isolation System – ISS Characterization Experiment
(ARIS-ISS) hammer tests were conducted last Friday with realtime video
downlink during the first two tests. Flight Engineer Carl Walz set up the
camera to give excellent close-up views of the locations where he tapped
with a small hammer. The video provided the science team on the ground with
new insight into their experiment results to date. Scientists observed on
the video that Walz occasionally bumped into the data umbilical between the
rack and the Station structure, which corresponded to occasional
disturbances observed in the data of previous hammer tests. That knowledge
will be useful in analyzing Friday’s hammer tests. ARIS was developed by
The Boeing Company. The ARIS-ICE experiment was developed by NASA’s Johnson
Space Center.
On Monday, the crew helped the Space Acceleration Measurement System (SAMS)
team by performing a microgravity disturbance test. To help track down some
unexplained vibrations registered by the SAMS sensors, the crew practiced
entering and exiting their Temporary Sleep Station restraints four times
while the ground team monitored.
The Microgravity Acceleration Measurement System (MAMS) this week is
downlinking acceleration data from one of its low frequency sensors. This
allows the science team to archive and monitor the Station’s low frequency
acceleration environment. The main influence at these frequencies is
aerodynamic drag caused by altitude and attitude and mass distribution. The
higher frequency sensor is currently disabled. MAMS will be recording
during the upcoming Shuttle docking and Station robot arm operations in
preparation for a planned spacewalk. Both SAMS and MAMS are managed by
NASA’s Glenn Research Center in Cleveland, Oh.
Gas, nutrient and condensate samples continue to be taken from the Advanced
Astroculture experiment. Scientists have been changing the growth
conditions inside the plant chamber to encourage the plants to flower and
produce seeds. The final sampling of the plants themselves will occur
today, with the sample placed in a fixative and then into the Biotechnology
Refrigerator (BTR).
The crew is scheduled to deactivate the crystallization cylinders in the
Protein Crystal Growth Single Thermal Enclosure System (PCG-STES) Unit 10 on
Thursday. The growth cylinders in the companion unit, STES 7, have already
been deactivated.
Locations scheduled to be photographed this week for the Crew Earth
Observations research program include: land clearing and wetlands activities
in the Irrawady River Delta, Bombay, India, Congo-Zimbabwe vegetation
burning, harvesting and vegetation clearing in the Parana River area in
South America, and lake levels in the Rukwa Transforma area of Tanzania.
During upcoming joint Shuttle/Station operations, when the Station solar
arrays are turned to accommodate Shuttle docking, the Payload Operations
Center will turn off two experiment racks to conserve power. EXPRESS Rack 1
will be powered down on Sunday and powered up prior to the Shuttle undocking
when the Shuttle undocks. EXPRESS Rack 2 will be powered down Thursday and
powered up on April 12.
When Space Shuttle Atlantis launches Thursday on mission STS-110, it will
carry the final five experiments planned for Expedition Four aboard the
Space Station. All five are scheduled to return on the STS-111 Shuttle
mission planned for late May.
The PESTO (Photosynthesis Experiment and System Testing and Operation)
experiment will be traveling inside the Biomass Production System – an
engineering development unit for a future Station plant habitat. PESTO will
study and determine whether plants will photosynthesize and transpire at the
same rates as on Earth.
The Protein Crystal Growth-Enhanced Gaseous Nitrogen (PCG-EGN) Dewar
experiment, which has flown to the Station on three earlier Shuttle
missions, is a passive experiment containing about 500 plastic tubes with
specific crystal growth experiments with potential applications in medicine
and agriculture. Students from California, Illinois, Indiana, Michigan,
Ohio and West Virginia helped prepare some 290 samples as part of their
classroom studies.
Also going up is the Commercial Generic Bioprocessing Apparatus (CGBA). It
contains experiments to characterize the effects of long-term exposure to
weightlessness on the process of fermentation, used in the production of
antibiotics. Antibiotic compounds are naturally produced by microorganisms
and can be used to fight a variety of infections. This experiment will
examine bacterial growth processes used to produce actinomycin D. This class
of antibiotics is used to treat certain types of cancer.
The Commercial Protein Crystal Growth (CPCG) experiment will be making its
second trip to ISS. The middeck locker-sized payload can carry up to 1,000
different samples of various proteins and other compounds, with the goal of
growing samples of greater quality. These higher quality – or
better-organized – crystals, are important to researchers who use techniques
such as X-ray crystallography, to determine the molecular structures of the
various compounds.
Atlantis will also carry the first samples for the Zeolite Crystal
Growth (ZCG) experiment. The furnace unit launched last December on STS
108, and has been checked out onboard the Station. The samples will be
loaded into the furnace about one week after the Shuttle undocks and will
grow for about two weeks. This experiment will be the first operational use
of the Active Rack Isolation System in EXPRESS Rack 2.
