Binary Colloidal Alloy Test - 3 (BCAT-3), Three Investigations
Research Area: Complex Fluids
Expedition(s): 8-13, 16-20, 27-ongoing
Principal Investigator(s): ● Peter N. Pusey, PhD and Andrew B. Schofield, PhD,
University of Edinburgh, Edinburgh, United Kingdom
● Arjun Yodh, PhD and Jian Zhang, University of Pennsylvania,
University Park, Pennsylvania
● David A. Weitz, PhD and Peter J. Lu, PhD, Harvard University,
Cambridge, Massachusets
RESEARCH OBJECTIVES
The Binary Colloidal Alloy Test-3 (BCAT-3) hardware supports 3 investigations in which
International Space Station (ISS) crews photographed samples of colloidal particles (tiny
nanoscale spheres suspended in liquid) to document liquid/gas phase changes, growth of
binary crystals, and the formation of colloidal crystals confined to a surface. Colloids are small
enough that in a microgravity environment without sedimentation and convection, they behave
much as atoms. By controlling aspects of colloidal mixtures, they can be used to model all sorts
of phenomena.
EARTH BENEFITS
The binary alloy (BCAT-3-BA)
study provides information that
may allow improvement of
fiber optics and allow
development of new
computers that process data
with light instead of electricity.
The surface crystallization
(BCAT-3-SC) investigation
provides information that may
identify the use of fields and
gradients to control order in
self-assembled colloidal
systems and microemulsions
for advanced materials. The
critical point (BCAT-3-4-CP)
investigation has numerous
applications in a wide variety of fields. Product shelf-life may be improved with a better
understanding of colloidal suspensions and have an enormous commercial impact.
SPACE BENEFITS
BCAT-3 addresses basic physics questions, but some of the areas may eventually have
applications for space exploration. The binary alloy (BCAT-3-BA) investigation examines colloids;
colloids are technologically interesting because they are the right size to manipulate light. The
ISS008-E-20613 (April 5, 2004) – Astronaut C. Michael Foale, Expedition
8 commander and NASA International Space Station science officer,
works with a Slow Growth Sample Module for the Binary Colloidal Alloy
Test-3 experiment.