Zeolite Crystal Growth (ZCG) Furnace Results

The crew
and ground-based science team completed the Expedition 5 ZCG experiments
on July 12, 2002. The samples will remain inside the deactivated furnace
until they are returned to Earth on STS-112 and replaced by a new set of
samples for mission 9A.

The
ZCG mission 8A experiment was completed on May 6—a day earlier than
originally planned.

ZCG
was the first payload to receive full-time support from the Active Rack
Isolation System (ARIS), a system that reduces vibration like shock-absorbers
on a car. ARIS underwent thorough testing throughout Increments 2, 3 and
4, and went online in April.

Space
grown zeolite crystals have proven to be larger and better-ordered than
Earth-grown crystals. Theoretically, it is possible to grow crystals in
microgravity that are 500 to 1000 times larger than terrestrially-grown
crystals. Zeolite A crystals grown during USML-1 achieved 96 percent area
and 175 percent volume increases over Earth grown samples, and approached
theoretically perfect aluminum/silicon ratios.

Applications

Zeolite
materials have great potential for commercial applications. Their shapes
form complex, open frameworks that act as absorbents or filters, and they
can be used in diverse ways: as absorbents for oil spills; to control
household odors; to filter ammonia from municipal wastewater; and as a
growth medium for hydroponic horticulture. They have been suggested as
nuclear waste scavengers and quantum confinement hosts for semiconductor
materials. Larger, better-constructed crystals, made possible by space-based
facilities, are more suitable for research and use in commercial materials.

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