*

NASA nominee to tell lawmakers he will "prioritize" Mars

missions

*

Delayed, over-budget programs "discouraging" for space

exploration, Isaacman says

*

Conflicting space interests obscure moon program's future

(Adds detail from written testimony in paragraphs 5, 11-12, and

background in 3-4, 6-8)

By Joey Roulette and David Shepardson

WASHINGTON, April 8 (Reuters) - President Donald Trump's

pick to lead NASA will tell senators on Wednesday that the

agency will prioritize an astronaut mission to Mars, while

noting that most U.S. space programs are over budget and behind

schedule.

"We will prioritize sending American astronauts to Mars.

Along the way, we will inevitably have the capabilities to

return to the moon and determine the scientific, economic, and

national security benefits of maintaining a presence on the

lunar surface," said Jared Isaacman, a 42-year-old billionaire

entrepreneur, in written testimony for his U.S. Senate Committee

on Commerce, Science, & Transportation confirmation hearing on

Wednesday.

Reuters reported on Monday that Isaacman told Senate staff

last week that returning humans to the moon before China sends

its own astronauts there is a national imperative. His remarks

allayed some concerns that NASA's multibillion-dollar moon

effort could be upended by Trump and SpaceX CEO Elon Musk's

focus on Mars as a top destination for U.S. astronauts.

NASA's Artemis moon program was spawned by Trump in his

first presidential term as an effort to speed up the U.S. return

to the moon, which would be used as a proving ground for

eventual, farther-off missions to Mars.

After his assurances to lawmakers about the moon strategy,

Isaacman's written testimony raises questions on whether his

prioritization of Mars would affect NASA's existing moon

missions or represent a rebranding of the program to give Mars a

more central emphasis in the space agency's strategy.

The billionaire nominee's stance on the program is expected

to be a major topic during his Senate hearing on Wednesday.

The agency has committed billions of dollars to its moon

program, involving U.S. allies and leaning heavily on dozens of

private companies - including Musk's SpaceX - that have set

their sights on a future lunar marketplace.

But in his second term, Trump has fixated on Mars in public

remarks, while Musk, who spent $250 million in support of

Trump's presidential campaign and pushed for Isaacman's

nomination, openly considers the moon a distraction from his

ultimate goal to send crews to the Red Planet.

Those views, as well as Musk's critiques of established NASA

contractors like Boeing ( BA ) and Northrop Grumman ( NOC ), which play key

roles in the Artemis program, have put the agency's primary and

over-budget moon rocket on thin ice, with its future uncertain

under a NASA led by Isaacman.

That rocket, built by Boeing ( BA ) and Northrop and

called the Space Launch System, has cost NASA over $20 billion

in development, an amount expected to more than double

throughout its future missions sending astronauts toward the

moon. Its first and only launch was in 2022 - a successful

uncrewed test - after years of delays.

Isaacman in his testimony said delayed and over-budget NASA

programs are "discouraging."

"This is discouraging because people look up at the stars

and wonder what is out there today, not decades down the road,"

his testimony said.