On their second try, Jeff Bezos and his rocket company have won a contract to take NASA astronauts to the moon.

NASA announced on Friday that it had awarded a contract to Mr. Bezos’ company, Blue Origin, to provide a lunar lander for a moon mission that is scheduled to launch in 2029. NASA agreed to pay $3.4 billion for the 50-foot-tall spacecraft, which is named Blue Moon and can transport four astronauts to the moon’s surface.

The mission, Artemis V, is another critical piece of NASA’s Artemis program to send astronauts back to the moon as part of an effort to explore its south pole region. Astronauts are to land on the moon in a vehicle built by SpaceX for the Artemis III and IV missions.

John Couluris, Blue Origin’s vice president for lunar transportation, said that the company was contributing “well north” of the price of the NASA contract amount to the development effort and that it, not NASA, would absorb any cost overruns. In the past, some members of Congress have complained about providing taxpayer money to Blue Origin, given Mr. Bezos’ wealth.

”We want more competition,” Bill Nelson, the administrator of NASA, said during the announcement on Friday at NASA’s headquarters in Washington. “It means that you have reliability. You have backups.”

Lisa Watson-Morgan, the manager for the human landing system program at NASA, said the second lander “also helps us with a more diversified industrial base, and that will help us advance innovation in the future.”

The winning of the contract could start a promising rebound year for Blue Origin after a number of delays and setbacks — including the failure of one of its New Shepard vehicles, which travel to space but not to orbit, during a launch last September that carried experiments but no passengers. Blue Origin has identified the cause and hopes to resume New Shepard flights involving both space tourists and scientific cargo later this year.

And some hardware manufactured by Blue Origin might finally be used on an orbital mission in the coming months. The company built engines for the booster stage of the Vulcan rocket being developed by the United Launch Alliance, a joint venture of the aerospace giants Boeing and Lockheed Martin.

Blue Origin might also provide some public glimpses of New Glenn, a much larger rocket that is to launch payloads to orbit.

For the lunar lander contract, Blue Origin, in collaboration with other aerospace companies such as Boeing and Lockheed Martin, beat a second team led by Dynetics, a defense company based in Huntsville, Ala.

“The feeling is absolutely fantastic,” Mr. Couluris said. “This is Step 1, though. We have a lot to do before we successfully land and return astronauts.”

The Blue Moon lander is designed to fit within the 23-foot-wide diameter of Blue Origin’s New Glenn rocket, and will weigh more than 45 metric tons when filled with propellants.

For Artemis V, the lander will first dock at Gateway, a small outpost in orbit around the moon. Four astronauts will travel to Gateway in another spacecraft, NASA’s Orion capsule. Then they will transfer to the Blue Moon lander for a stay near the lunar south pole lasting about a week.

After their visit to the moon, the lander will blast off and return to Gateway, and the Orion capsule will take all four astronauts back to Earth. The same lander could be used for several missions.

A second Blue Origin spacecraft will be needed to transport liquid hydrogen and liquid oxygen from Earth to lunar orbit to refill the propellant tanks of the Blue Moon. Transfer of propellants in the near-weightless environment of space, especially ultracold liquid hydrogen, is tricky and has not yet been demonstrated on a large scale.

Mr. Couluris said Blue Origin would conduct an uncrewed demonstration flight of the lander in 2028, a year before it is to be used for astronauts.

“We fully expect to meet the NASA schedule,” Mr. Couluris said.

Mr. Couluris said the lunar lander could also be configured to carry 30 metric tons of cargo instead of passengers, “to form the foundation of habitats and other permanent infrastructure” on the moon’s surface.

The Artemis V mission was the second bid by Mr. Bezos’ company to land on the moon. In 2021, Blue Origin and Dynetics were disappointed when NASA awarded SpaceX a fixed $2.9 billion contract to build a variation of its giant Starship vehicle that would land astronauts on the moon for the first time in more than half a century.

The two companies protested the decision, especially because NASA officials originally aimed to award two contracts.

That would have paralleled successful efforts by NASA that turned over to private companies the transportation of cargo and crew to the International Space Station. But NASA officials said at the time that there was not enough money in their budget for a second lander. SpaceX’s $2.9 billion bid was the lowest bid by far. Blue Origin’s proposed design had a price tag of $6 billion, and the one offered by Dynetics was even more expensive.

The federal Government Accountability Office rejected the protests of the two companies. Blue Origin then sued in federal court and again lost.

Last September, after winning a larger budget from Congress, NASA announced a competition for a second lunar lander. Dynetics and Blue Origin decided to compete again, though there was some shuffling of the companies participating in the efforts. Northrop Grumman, which was part of Blue Origin’s original proposal, switched to the Dynetics team.

Blue Origin added to its team Boeing; Astrobotic, a small Pittsburgh company that is developing robotic lunar landers; and Honeybee Robotics, a space technology company that Blue Origin bought last year.

The design of the spacecraft also changed, adding in-space propellant transfer.

But it will not reach the moon for a while.

SpaceX’s initial $2.9 billion contract was to provide the lander for the first moon landing during Artemis III, which is currently scheduled for late 2025 but is likely to slip to 2026 or later. In November, NASA exercised a $1.15 billion option in that contract for SpaceX to provide a lander for Artemis IV as well, a mission that is scheduled for 2028.

After Artemis V, NASA will be able to choose between the SpaceX and Blue Origin designs for later missions.

Eventually, companies and people outside of NASA could also buy Blue Moon rides. “We do have a number of entities that are interested,” Mr. Couluris said.