There is auto saves set by the mission design and manual saves usable by the player.
One can limit the manual saves to one per mission via difficulty settings (or scripting).
The difficulty setup we have in mind so far:
For manual saves its planned to have before and after relevant combat situations.Recruit: Unlimited manual saves, autosaves
Regular: Unlimited manual saves, no autosaves
Veteran: One manual save, no autosaves
Elite: No manual saves, no autosaves