Foam fractionation of heavy particles has been obtained aboard an airc
raft that provides a low-gravity environment by flying parabolic traje
ctories. Results for large silica, glass, and steel pellets (>0.2 mm)
show that, using minimally supporting froths, both mass transport and
separation are possible. For single-pass batch separations in low grav
ity, concentration factors reached threefold (compared with a ninefold
theoretical limit and no separation in unit gravity). The impact of r
educed gravity is discussed for splitting large particle sizes from lo
w surfactant fluids; possible interest includes bubbling premium biolo
gicals (whole cells, proteins, and viruses, etc.) from native solution
s without surfactant addition or membrane disruption.