BIG SPENDER: How Jeff Bezos is using Amazon’s success to fuel Blue Origin’s space effort, a billion dollars at a time.

“My business model right now for Blue Origin is, I sell about $1 billion a year of Amazon stock, and I use it to invest in Blue Origin,” he told reporters here at the 33rd Space Symposium. “So the business model for Blue Origin is very robust.”

Bezos threw out the figure half-jokingly, after noting that he typically doesn’t reveal how much he’s spending. But he made clear that his in-house space effort, headquartered in Kent, Wash., takes a noticeable chunk out of his estimated $78 billion fortune.

He said the development cost for Blue Origin’s New Glenn orbital launch system, which should be taking off from a Florida launch facility by 2020 or so, is likely to be on the order of $2.5 billion.

Some small part of my $99-a-year Prime membership is going into space.