In this paper we describe the use of our planning and scheduling framework, HSTS, to support science mission planning. This work is part of an overall project to enable a small team of scientists to control the operations of a spacecraft. The present process is essentially carried out by human operators. Users (scientists and operators) rely on a non-codified understanding of the different spacecraft subsystems and of their operating constraints. They use a variety of software tools to support their decision making process. A successful use of AI planning and scheduling technology must consider the types of decision making that need to be supported/automated, the nature of the domain constraints and the capabilities needed to address them successfully, and the nature of external software systems with which the core planning/ scheduling engine needs to interact.