Fact sheet number: FS-2001-11-194-MSFC
Zeolites have a rigid crystalline structure with a network of interconnected tunnels and cages, similar to a honeycomb. While a sponge needs to be squeezed in order to release water, zeolites give up their contents when they are heated or under a reduced pressure. The name "zeolite" comes from the Greek words zeo (to boil) and lithos (stone), literally meaning "the rock that boils." Zeolites have the ability to absorb liquids and gases such as petroleum or hydrogen - but remain as hard as a rock.
Zeolites form the backbone of the chemical processes industry, and virtually all the world's gasoline is produced or upgraded using zeolites. Industry wants to improve zeolite crystals so that more gasoline can be produced from a barrel of oil, making the industry more efficient and thus reducing America's dependence on foreign oil.
To facilitate this goal, as well as to look at new applications for zeo-type materials, the Center for Advanced Microgravity Materials Processing (CAMMP) at Northeastern University in Boston, Mass. -- one of 17 NASA Commercial Space Centers - works with industry and academia to grow zeolite crystals and zeo-type materials in space. Results from three Space Shuttle experiments have shown that larger, better quality crystals can be grown in microgravtiy - the low-gravity environment created as the Space Station orbits Earth.
The Zeolite Crystal Growth Furnace Unit, also known as the ZCG-FU, is designed for relatively low-temperature growth of crystals in solutions. The experiment has three main objectives:
Before the flight, two solutions are loaded into metal, Teflon-lined, cylindrical containers, called autoclaves. The solution combination is proprietary and determined by the industry partner before the flight.
The zeolite furnace will be delivered on Expedition Four, ISS Flight UF-1, STS-108 Space Shuttle Flight, scheduled for late November 2001. The crew will install the hardware into a double middeck locker in EXPRESS Rack 2. The hardware will be checked out during UF-1 before the Space Shuttle delivers samples during Expedition Four, ISS Flight 8A, STS-110 Space Shuttle Flight, scheduled for late March 2002.
When the autoclaves containing the sample solutions arrive, the crew will unstow them and load them in the furnace. The Improved Zeolite Electronic Control System (IZECS) will issue computer commands to the furnace to heat the samples. The IZECS is operated remotely by scientists working on the ground at a CAMMP telescience center on the campus of Northeastern University in Boston, Mass.
As the furnace heats up and crystals start to form, or nucleate, the crew will monitor the experiment periodically. The payload team on the ground also will be monitoring the experiment's progress via downlink telemetry. With the exception of loading the autoclaves into the furnace and turning the switch on, the crystal growth experiment operations are unattended by the crew.
At the end of the specified processing time, the crew will power down the furnace, unload the autoclaves containing the crystals and stow them for return to Earth.
The Zeolite Crystal Growth Furnace Unit consists of the Furnace Module and the Improved Zeolite Electronic Control System. They are mounted together with a backplate in a double EXPRESS Rack locker configuration. The crew will install the unit into EXPRESS Rack 2.
A set of 19 Teflon-lined aluminum or titanium autoclaves fit inside the furnace. Before the flight, scientists will load two solutions in each autoclave. Inside each autoclave, a motor will mix the two solutions, according to procedure and protocol commands sent by scientists working on the ground in the CAMMP remote operations center. Data from the furnace and control system will be sent through the EXPRESS Rack 2 computer to scientists working on the ground.
A simpler version of this experiment has flown successfully on three prior Space Shuttle missions: STS-50, June 25-July 9, 1992; STS-57, June 21-July 1, 1993; and STS-73, Oct. 20-Nov. 5, 1995. Dr. Al Sacco, director of the Center for Advanced Microgravity Materials Processing, served as the payload specialist operating the experiment in space during STS-73.
During these earlier flights, zeolite crystals grown in space were larger and of better quality than crystals grown in a similar facility on the ground and responded significantly different to catalytic test reactions. Research aboard the Shuttle is continuing with similar experiments scheduled for the STS-107 mission in 2002.
The series of zeolite experiments that begin on Expedition Four will enhance this research significantly because it will allow crystals to grow for longer periods. This will result in even larger crystals - making it easier for scientists to study the internal structure of different types of zeolites.
The Space Station also will allow scientists to study results and repeat experiments, modifying experiment conditions to improve the quality of crystals. For the first time, researchers will be able to perform repeated experiments in a microgravity laboratory - using the same repetitive process they use for experiments in ground-based laboratories.
Are other forms of energy -- as well as less dependence on foreign oil and less pollution -- in America's future? Research with zeolites has the potential to reduce our dependence on foreign oil and the pollution associated with producing gasoline and other petroleum products.
When zeolites are produced on Earth, zeolite crystals are extremely small - roughly 2 to 8 microns, about the size of microscopic bacteria. To better define the structures of zeolites, scientists need to grow crystals 200 to 1000 times larger. In microgravity, materials come together more slowly, allowing zeolite crystals to form larger and with better internal order. These larger crystals tell scientists more about the way they are made and how they work.
In the future, zeolites may even be used for storing new fuels that are cheaper and cleaner. Hydrogen is one candidate fuel that might be stored and transported safely using zeolites. Since hydrogen is the most abundant element in the universe, and it's pollution-free, it is an ideal fuel. Scientists are seeking a solution to the efficient storage of hydrogen, and zeolites and zeo-type materials are being tested as possible storage mediums.
The Center for Advanced Microgravity Materials Processing also is studying other uses for improved zeolites, including detergents, optical cables, gas and vapor detection for environmental monitoring and control, and chemical production techniques that significantly reduce hazardous by-products.
More information on this experiment and other experiments are available at: