  We study the association and dissociation dynamics of weakly bound
heteronuclear Feshbach molecules using transverse RF-fields for expected
parameters accessible through the microgravity environment of NASA's Cold Atom
Laboratory (CAL) aboard the International Space Station, including temperatures
at or below nK and atomic densities as low as $10^8$/cm$^3$. We show that under
such conditions, thermal and loss effects can be greatly suppressed resulting
in high efficiency in both association and dissociation of Feshbach molecules
with mean size exceeding 10$^4a_0$, and allowing for the coherence in
atom-molecule transitions to be clearly observable. Our theoretical model for
heteronuclear mixtures includes thermal, loss, and density effects in a simple
and conceptually clear manner. We derive the temperature, density and
scattering length regimes of $^{41}$K-$^{87}$Rb that allow optimal
association/dissociation efficiency with minimal heating and loss to guide
future experiments with ultracold atomic gases in space.
