Table of Contents

A Guide to Microgravity for All Ages

Canadian Research in Microgravity Sciences

Canada has achieved many firsts in microgravity research and maintains a position of technical and scientific excellence. Microgravity research has worldwide commercial applicability. The strategic application by Canadian industry of advances in microgravity research will enable Canada to maintain its position as a world leader in research and the commercial application of science, well into the 21st century, enhancing its economic competitiveness, and creating jobs and employment for Canadians.

Examples of ongoing Canadian research and development in microgravity in the following fields are given below.

• Fluid Physics
• Glass Manufacturing
• Crystal Growth
• Ceramics
• Biotechnology: Protein Crystallization
• Materials

Fluid Physics

Application: Multi-disciplinary

Canada is conducting research into fundamental sciences affected by microgravity such as fluid physics. Microgravity environments are characterized by a drastic reduction in hydrostatic pressure, sedimentation, and convection due to buoyancy. These characteristics affect virtually all processes involving fluid phases.

Gravity has a dominant effect on fluids on earth. The elimination of gravity which acts in one direction allows us to study and utilize smaller forces such as surface tension whose direction is a function of the fluid shape. Surface tension can be used to pump fluids, partition fluids, move bubbles, and even act as the container. Canada is building a float zone furnace for the production of high purity materials. Surface tension is used to replace the container walls which would contaminate the material. Understanding the influence of these forces in microgravity extends Canada's grasp on fluid physics and enhances its ability to create and control processes thus developing new products for many different applications.

Glass Manufacturing

Application: Fibre Optic Cables

Canada is conducting research in glass manufacturing in microgravity. Fluorozirconate is a material used to make fibre optics. In the manufacturing process on earth some crystal formation occurs, and crystals reduce the ability of glass to transmit light. The manufacture of fluorozirconate glasses in microgravity reduces crystal formation. Today fibre optic cables require repeaters or boosters every five to ten kilometres. Researching glass formation in microgravity will assist Canada to develop fibre optic cables able to transmit a signal without repeaters across the Atlantic Ocean, a distance of 3200 km. This will enhance and extend Canada's role as a preeminent nation in global telecommunications.

Crystal Growth

Application: Electro-optical and Photonic Equipment

Gravitational effects such as convection currents, sedimentation and hydrostatic pressure variation reduce the uniformity of crystals grown in a gravity environment. Also, uncontrolled nucleation at the container walls leads to imperfections in crystal structure as well as the presence of impurities in the crystal lattice. These factors reduce crystal size and purity, which are critical parameters in crystal performance.

Canada is researching crystal growth in microgravity where convection, sedimentation and hydrostatic pressure variation are substantially reduced. The resulting crystals show significant improvements in crystal structure, purity and uniformity. In addition, containerless processing will reduce contaminant presence in crystal lattices, further improving crystal purity and process yields. Crystals manufactured in microgravity will be used to create high precision, high power lasers, microwave broadcast devices, more sensitive heat sensors, and higher resolution video cameras.

Ceramics

Application: High-Temperature Applications

The role of microgravity in improving ceramics is similar to that in improving crystals. Containerless processing of ceramics will reduce contaminants, and both uniformity and purity will be improved by using a microgravity environment.

Advanced ceramics created by Canada in microgravity exhibit desirable mechanical properties such as creep stability, impact resistance and strength. Furthermore, they maintain these properties at high temperatures, giving them a significant advantage over metal alternatives. These new ceramics will be used to replace metals where high temperatures limit the usefulness of metals. For instance, advanced ceramics can be used to coat the blades in hydroelectric turbines. The blades will be stronger and last longer, resulting in fewer breakdowns.

Biotechnology - Protein Crystallization

Application: New Treatments For Human And Plant Disease

Canada is conducting research to determine the structure of proteins in living things. The process or research methodology is called protein crystallization. Proteins which exist in liquid solutions are first crystallized and then analyzed with X-ray diffraction to determine the protein structure. Proteins crystallized in microgravity are often larger and of higher quality than crystals grown on earth, facilitating structure determination. Knowledge of the protein structure can be used to design more effective drugs to combat disease in both plants and humans. Protein crystallization has been used to determine the structure of viral shells, which protect a virus from the body's natural immune system. Using results from protein crystallization, Canadian researchers will be able to develop drugs to break down the shell and permit the body to attack and destroy the virus.

Materials

Application: Metals and Alloys

Alloys are made by mixing two immiscible liquid metals together and letting them solidify. If a mixture of oil and water is shaken, the oil droplets spread through the water. Freezing the mixture simulates an alloy - droplets of one material distributed in a matrix of another. The strength of an alloy increases as droplets become smaller and as droplet distribution becomes more uniform.

Gravity affects both of these parameters. Droplets are usually of a different density than the matrix, so sedimentation causes them to settle, reducing the uniformity of droplet distribution as the mixture hardens. Droplets of different weight settle at different rates, quicker droplets merging with slower droplets to create larger ones. This is agglomeration. Sedimentation is absent in microgravity so droplets don't collide and agglomerate, resulting in smaller droplets, uniform distribution and therefore stronger alloys. Canada's microgravity alloying research will advance our understanding of metal behaviour and enhance alloy production on earth.