NASA Administrator Jared Isaacman is moving ahead with the agency's ambitious push to return astronauts to the moon, unveiling new plans for a lunar base alongside a nuclear-propelled spacecraft intended to pave the way for a future Mars mission.

At an earlier event, The New York Times reported that Isaacman laid out the agency's three-phase plan: first, expand robotic missions and surface systems; second, build semi-habitable infrastructure for regular astronaut visits; and third, construct permanent infrastructure for a sustained human presence on the moon.

"We are calling today's event Ignition because it represents the start of a transformative journey for NASA," Isaacman told an audience of representatives from aerospace companies, international space agency officials, and Congress.

Isaacman's top objective is to return astronauts to the moon in a series of missions called Artemis by 2028. At the same time, he outlined plans to launch a nuclear-propelled spacecraft to Mars by the end of 2028.

He said NASA will deploy $20 billion over seven years to ensure America leads the Moon and Mars missions.

"The moon base will not appear overnight," Isaacman said. "We will invest approximately $20 billion over the next seven years and build it through dozens of missions."

The announcement comes just ahead of Artemis II, the mission expected to send astronauts around the moon and back for the first time since 1972.

Isaacman also said Artemis missions would accelerate to twice a year after Artemis V in 2028, and NASA is seeking replacements for Boeing's Space Launch System, or SLS, rocket and Orion capsule. We reported this last week. 

He added that work on the planned Gateway lunar station program has been suspended.