What new or enhanced feature are you proposing? A "Save as draft" button which allows students to save their proposal (and abstract) to the server, but does not count a submit. Students would then later be able to open up their proposal form for the same org and continue were they left off.

What goal would this enhancement help you achieve? This would allow students to work on their proposal for a short while and come back later. Or for example fill in certain areas that can be filled in immediately (name / mail etc.) and then start working on whatever tests /tasks the organization requires for their proposals.