The seats are being offered via a sweepstake hosted by Omaze. The two seats up for grabs—one for the winner and one for a guest—are estimated to be worth $510,000 in total.

To enter, participants must enter their details on the Omaze website and hope they are lucky enough to win.

The closing date for entries is September 1, 2021. The winner is expected to be announced on September 29, and the experience itself is estimated to take place in early 2022.

More entries can be purchased by making a charitable donation via Omaze’s website. A donation of $10, for example, rewards users with 100 entries.

However, Omaze notes that a donation will not increase the chances of winning.

The money donated is given to Charities Aid Foundation America (CAF America), which then sends a portion of the money to Space for Humanity—an organization that aims to provide opportunities for citizens to go to space.

Omaze states that typically between 65 to 75 percent of donations given towards any of its sweepstakes are used to pay for the cost of the experience itself.

Rachel Lyons, executive director of Space for Humanity, said in a press release that the organization was “incredibly grateful” to Virgin Galactic and its founder Richard Branson.

Lyons said: “It is my hope that by democratizing access to space, we will collectively renew our relationship with our planet, and each other, allowing for a prosperous future on and off the planet.”

The sweepstake comes after Virgin Galactic launched its first fully-crewed sub-orbital spaceflight on Sunday, with Branson on board.

The spaceplane, called VSS Unity, reached a height of around 53.5 miles (282,000 feet) before gliding back down for a runway landing at Spaceport America in New Mexico.

The test flight was Virgin Galactic’s fourth crewed spaceflight and the 22nd flight test overall for VSS unity.

Virgin Galactic CEO Michael Colglazier called the flight “a landmark achievement for the company and a historic moment for the new commercial space industry.”

Branson said he had “dreamt about this moment since I was a child.”

Unlike other aerospace companies, Virgin Galactic does not use vertical rockets to go to space. Instead crew members board a spaceplane that is carried to around 50,000 feet by another, larger plane.

It is then released mid-air, and a rocket engine takes the spaceplane the rest of the way to space.