A cleanroom is used for zeolite synthesis.

Ovens are used to synthesize zeolites and
zeo-type materials.

Zeolite Crystal Growth (ZCG)

Rich Miller, Maria Shelby, Julo Warzywoda, Alby Sacco, Mike Manning, and Al Sacco, Jr.

Payload Objectives

The Zeolite Crystal Growth (ZCG) mission is to develop commercial dual use technology for NASA’s exploration missions and commercial products through knowledge gained from ground-based and, where appropriate, microgravity research. The synthesis of zeolite / zeo-type materials in the microgravity environment is currently being investigated in the International Space Station (ISS).

The objective of the ZCG facility is to provide a sufficiently versatile experimental facility for solution crystal growth studies that meet practical demands and requirements of the Center for Advanced Microgravity Materials Processing (CAMMP), its Industrial Partners, and the scientific community at large. The ZCG name originated from early shuttle flight experiments limited to the growth of zeolite crystals, but has since grown to include other materials of significant commercial interest using the solution method of crystal growth. Materials of current interest include zeolites and titanosilicates. Requirements to be met by this apparatus include the effect on crystal morphology of subtle changes in chemical formulation of solutions, production of crystals with fewer defects for the study of intrinsic properties, larger sizes for the study of bulk related properties, improved yield for scaled industrial process testing, and reduced dissolution which causes degradation of crystals and their size once the growth phase has been terminated.

ZCG experiments have flown on four STS missions (STS-50 (USML-1), STS-57, STS-73 (USML-2) and STS-107) and four ISS missions (8A, UF-2, 9A and 11A).

ISS Experimental Hardware

The ZCG facility at this time consists of a ZCG Furnace Unit (ZCG-FU), the High Temperature Furnace (HTF), and the Improved Zeolite Electronic Control System (IZECS). Each furnace has several mechanically complex crystal growth autoclaves, suitable for use with a particular furnace. The ZCG facility is designed to grow into four independent furnaces controlled by IZECS. IZECS provides monitoring of critical parameters, data logging, safety monitoring, air-to-ground control, and operator interfacing. It is capable of controlling any combination of the four furnaces at the same time. IZECS interfaces with an Expedite Processing of Experiments to Space Station (EXPRESS) Rack Interface Controller (RIC) through an Ethernet communication link. This permits a two-way command and data link with ground based stations for data downloading and ground commanding. The on board Portable Computer System (PCS) is available to ISS crew for high level local troubleshooting and special commanding of IZECS.

ISS Remote User Facilities

ZCG maintains two remote operations support centers located at Northeastern University in Boston, MA and Intek, Inc. in Westerville, OH. Each site maintains voice systems and Enhanced HOSC System (EHS) workstations with access to the Payload Operations and Integration Center (POIC) networks. Each is capable of monitoring and controlling the experiment on orbit by supporting interaction with the cadre over the console networks, telemetry processing, and ground commanding of the experiment.