No clue? Their Kickstarter page currently has stretch goals listed covering up to $1 million. Their site (linked from the Kickstarter) explains they estimate needing $5.45 million for the entire project - which I assume includes the parts they've completed, including the test launch this month - and that they have raised $4.2 million of that so far. They seem to have a handle on what they want to do with the money. They aren't building a mysterious slush fund.
It's hard to guess at how much they will raise in the end, but complex projects often go over budget or suffer technical issues. Any extra money not accounted for by their stated goals will likely go towards those things.