A prominent defense analyst believes tech billionaire Jeff Bezos’ funding of Blue Origin by selling his Amazon [AMZN] stock is formidable as it is a constantly replenishing pool of money for Bezos to tap.

Byron Callan of Capital Alpha Partners said April 10 it is likely Bezos, who founded both the Amazon online marketplace and Blue Origin space company, is getting annual stock awards as part of his compensation for running Amazon. Bezos said April 5 at the Space Symposium in Colorado Springs, Colo., that he’s funding Blue Origin by selling about $1 billion in Amazon stock.

As opposed to funding Blue Origin via, for example, a home equity loan with a finite amount of money, Callan said Bezos is getting equity back by selling his Amazon stock. Amazon, at the close of business April 10, was selling at $907 per share on Nasdaq.

“Clearly his wealth or value is going to be dependent on new stock options or stock awards running Amazon,” Callan said. “When he says he’s going to sell…$1 billion (in shares), he’s got a lot of stock. I think that’s the important part.”

Callan said that, according to a SEC filing, as of February 2016, Bezos owned 80,897,696 shares of Amazon stock which was 16.95 percent of the total shares outstanding.

Bezos clearly said the week of April 3 he does not want Blue Origin’s current business model of being funded via his Amazon shares to last forever. Bezos said he wants Blue Origin to be a sustainable enterprise capable of standing on its “own two feet,” not simply a non-profit.

“It’s a long road to get there and I’m happy to invest in it,” Bezos said.

Bezos said he has an unwavering commitment to reducing the cost of access to space. By lowering the cost of accessing space, Bezos said the launch services market, which he called too small at $2.5 billion, will see the same creativity and dynamism the e-commerce industry has seen since the Internet became widely available in the mid ‘90s. Bezos said the commercial aviation industry would have a small market, too, if airplane flight costs were the same as in 1940.

Standing in front of his New Shepard suborbital rocket on display outside of an entrance at the Broadmoor hotel and resort, Bezos said New Shepard, which has flown five times, has required a very small amount of refurbishment between flights. Blue Origin, he said, had to touch up the thermal protection system on the aft, which he called easy. Bezos said the company is implementing its lessons learned from New Shepard into its New Glenn orbital rocket, which hasn’t flown. Both New Shepard and New Glenn will be reusable.

Blue Origin plans to use New Shepard for space tourism. Bezos said this is important as it will help the company practice much more. He lamented how companies flying 12 times per year is considered a good year and that he hopes tourism can help lead Blue Origin to flying at a much higher frequency.

“I wanted to start with a high flight rate New Shepard launch vehicle, learn those lessons at this scale and then build New Glenn, already knowing all those lessons, designed from the ground up to be reusable,” Bezos said.

Bezos said he hopes to have commercial customers flying in New Shepard by 2018, but he’s not in a rush to make a deadline. He also said the vehicle would begin test flights when it’s ready, plus. Bezos also said it would be interesting to build a second stage for New Shepard as it would allow the company to use the rocket to deliver small sats.

Blue Origin is also in a competition with Aerojet Rocketdyne [AJRD] and its AR1 to provide its BE-4 first stage engine for United Launch Alliance’s (ULA) new Vulcan launch vehicle. Though ULA won’t say publicly which engine it has selected, Blue Origin, on its webpage, says ULA has chosen BE-4. A Blue Origin source told sister publication Defense Daily April 5 this is not an oversight and that the company is taking ownership of providing the BE-4 to ULA. ULA is a joint venture of Lockheed Martin [LMT] and Boeing [BA].