I rather doubt any bank would lend you money if you intend to use it to put yourself on Mars. Maybe unless they were satisfied the risks were low enough and confident that you would continue to have an income of money that could be used to pay back an Earth debt. Even then there is the issue of collateral.

I suspect Mars will be only for those with a total net worth of at least 500k (selling all of your Earth assets to get there probably makes sense).