Elon Musk's Starship won't be astronauts' only ticket to the moon for long.

A year after the space agency awarded SpaceX the sole contract to develop a human landing system for the program, it's now asking companies for new lander concepts. 

"Competition is critical to our success on the lunar surface and beyond," NASA Administrator Bill Nelson said in a statement Wednesday. 

That competition won't really begin until after Starship takes the first crew of Artemis astronauts to the lunar surface as part of the Artemis III mission as soon as 2025. SpaceX is still the sole contractor for that mission and is also required to land an uncrewed Starship on the moon before NASA will let astronauts make the same voyage. 

The additional lander concepts will be for missions after Artemis III. Like Starship, they will have to be able to dock to NASA's yet-to-be-launched lunar Gateway, a sort of waystation for experiments, crew and supplies in orbit around the moon. From there, the vehicle needs to be able to ferry its cargo down to the surface and back. 

"Under Artemis, NASA will carry out a series of groundbreaking missions on and around the moon to prepare for the next giant leap for humanity: a crewed mission to Mars," Nelson added.

Last April, NASA selected only SpaceX to develop its new lunar lander, prompting appeals from Blue Origin and Dynetics, which both submitted concepts that weren't selected. NASA had originally hoped to select two lander designs, but Congress appropriated sufficient funding for only one. 

In the end, the protests were rejected, and SpaceX and NASA are currently working together on the first human lander to return to the moon in over 50 years. 

"Blue Origin is thrilled that NASA is creating competition by procuring a second human lunar landing system," a company spokesperson said via email Wednesday. "Blue Origin is ready to compete and remains deeply committed to the success of Artemis. We will continue to work with NASA to achieve the United States' goal to return to the moon as soon as possible."

Dynetics didn't immediately respond to a request for comment.

In a press conference Wednesday, Nelson said he expects the Biden administration to include funding for the additional lander design in its upcoming 2023 budget request to Congress.

NASA also made it official that it would like to work with SpaceX to use Starship for missions after Artemis III as well, meaning it would be in direct competition with whatever new company is chosen to deliver a lander.

"We expect to have two companies safely carry astronauts in their landers to the surface of the Moon under NASA's guidance," said Lisa Watson-Morgan, program manager for NASA's Human Landing System Program.

NASA says it will put out a draft request for proposals in the coming weeks.