In an open letter to NASA Administrator Bill Nelson, the founder of Amazon and Blue Origin offered to cover up to $2 billion in costs to build a lander that would take astronauts to the moon in exchange for a contract to build the device.

“Blue Origin will bridge the HLS [Human Landing System] budgetary funding shortfall by waiving all payments in the current and next two government fiscal years up to $2B to get the program back on track right now,” wrote Bezos. “This offer is not a deferral, but is an outright and permanent waiver of those payments. This offer provides time for government appropriation actions to catch up.”

The offer comes nearly four months after SpaceX received a $2.89 billion contract to build a crewed lunar lander.

Bezos argued that relying on a single company to work on the system could result in delays or escalating costs.

“NASA should embrace its original strategy of competition,” he wrote. “Competition will prevent any single source from having insurmountable leverage over NASA. Without competition, a short time into the contract, NASA will find itself with limited options as it attempts to negotiate missed deadlines, design changes, and cost overruns.”

Bezos, on July 20, was one of Blue Origin’s first passengers, part of an 11-minute flight to the edge of space, along with his brother, Mark; Wally Funk, 82, a former astronaut trainee; and Oliver Daemen, the 18-year-old son of a Dutch financier.

The company says it has already sold over $100 million worth of tickets to future passengers.