  Existing space-based cold atom experiments have demonstrated the utility of
microgravity for improvements in observation times and for minimizing the
expansion energy and rate of a freely evolving coherent matter wave. In this
paper we explore the potential for space-based experiments to extend the limits
of ultracold atoms utilizing not just microgravity, but also other aspects of
the space environment such as exceptionally good vacuums and extremely cold
temperatures. The tantalizing possibility that such experiments may one day be
able to probe physics of quantum objects with masses approaching the Plank mass
is discussed.
