It will cost Blue Origin's New Shepard suborbital spacecraft first passengers at least $2.8 million to fly.

Jeff Bezos' Blue Origin is auctioning off one of New Shepard's six seats for the vehicle's first crewed flight - set to launch July 20. The auction began with sealed online bidding May 5 and progressed to the unsealed phase May 19.

The current winning bid, according to the Blue Origin website, is $2.8 million.

And that number is almost going up, for sure. The "unsealed online bidding" runs through June 10, with a live auction June 12.

The winning bid won't add to Bezos' wealth. He's already the richest person in the world. The money "will be donated to Blue Origin's foundation, Club for the Future, to inspire future generations to pursue careers in science, technology, engineering and math and help...the future of life in space," according to a description of the auction on the company's website.

New Shepard is a rocket and a capsule - both reusable. The capsule lands back on Earth using parachutes. New Shepard has flown 15 unmanned test flights to suborbital space from Blue Origin's West Texas facility. The most recent mission, an "astronaut rehearsal," took off April 14.

The first crewed flight is planned for July 20. Blue Origin hasn't said how much it will normally charge for seats on New Shepard - but it's a safe bet it won't be more than $2.8 million. 

Virgin Galactic, the company's main competitor in the suborbital space tourism market, recently announced a ticket price of $250,000.