If the key was only stored locally, you wouldn't be able to restore the data in case of hardware failure. I would guess that Space Monkey itself has access to the key and the data.
> Your data is still accessible even if you are outside of your home and your home ISP experiences an outage."
In light of the RSA reference it seems like they encrypt every thing with a user pubkey and a company pubkey. Without the company pubkey there would be no way to access your data when you were not at home.
Is Space Monkey a turn-key backup solution? E.g. if my SM drive explodes, can I get my data back with a new SM drive?