CSTART has very limited resources, in a lot of senses: active community members, administrative infrastructure, server space and money. Until such time as this changes, CSTART is adopting a conservative approach to project formation: we don't want to have too many things going on at once. Project proposals should not represent huge leaps in scope or ambition beyond existing projects. We need to prove that an open source, collaborative space agency can successfully walk before trying to make it run, and that it can run before trying to make it fly (don't take this literally, of course, we'll be literally flying from the start).
Please read the CSTART Desgin Philosophy and keep it in mind when making proposals. We are about keeping things simple and leveraging existing technology wherever possible to minimise costs (financial, technological and otherwise) involved in getting into space. CSTART is not going to build a nuclear reactor powered VASIMR engine at any stage in the forseeable future.
Wherever possible, projects should be designed to either allow reuse of existing ideas and designs from previous projects, or to provide realistic test applications for ideas and designs involved in active projects which are some time away from seeing implementation. We don't want to spread ourselves too thin. Build on our existing strengths wherever possible.
Finally, don't let the above "warnings" make you feel too constrained. Be creative, be innovative, be optimistic, and be inspired! Just try to be these things in a realistic and responsible fashion. 