That is possible.
There is a option "Participants may save and resume later" in the survey settings.
Participant may save and resume later?: This setting allows a participant to save his responses and resume to answer the survey at a later time. Please note that this makes most sense with open surveys or surveys with anonymized answer. If you are using tokens and the survey is not anonymous in most cases it is better to activate 'Token-based response persistence' in the token tab.
Personally I would try to get valid results from an one hour survey.
What is the topic of the survey?