NASA'S ACTING LEADER WILL LEAVE WITH NO OBVIOUS SUCCESSOR

NASA will lose its temporary leader at the end of April, a move that could force Congress to decide who will take the helm of the space agency as it heads into a decade focused once again on human exploration.

Robert Lightfoot, the agency's acting administrator, announced this week that he will step down April 30, ending his 14-month tenure as the temporary head of NASA.

Lightfoot informed his colleagues Monday in a memo that praised the space agency's mission.

"The grit and determination you all demonstrate every day in achieving our missions of discovery and exploration are simply awe inspiring," he wrote. " I leave NASA blessed with a career full of memories of stunning missions, cherished friendships, and an incredible hope for what is yet to come."

He continued, "NASA's history has many chapters with each of us having a part. I've written my part and now the pen is in your hands - each one of you."

Lightfoot was named acting administrator Jan. 20, 2017, after serving as deputy administrator for about five years. Prior to that, he was director of the agency's Marshall Space Flight Center in Alabama.

He now holds the record for longest-serving interim leader of the space agency.

Keith Cowing, editor of NASA Watch, a website devoted to space news, said Lightfoot's announcement likely will put pressure on the U.S. Senate to confirm a permanent leader.

"I think this will push the Senate to do something," Cowing said Monday.

Rep. Jim Bridenstine, a Republican from Alabama, was nominated by President Donald Trump to serve as the agency's permanent leader in September 2017, a nomination that was resubmitted in January. But that nomination must be confirmed by the Senate.

Bridenstine would be the first politician to lead the agency, but there do not appear to be enough votes in the Senate for him to win confirmation.

With Bridenstine's confirmation in limbo, Lightfoot has been tasked with much more than acting leaders are typically expected to do.

Lightfoot was given the position to keep the train on the tracks, Cowing said, and ended up having to prepare the agency's 2019 fiscal year budget proposal.

"I think when Lightfoot accepted this job, he did not expect to be there for more than a year," Cowing said. "This has been unusual. Half a year at most is what you'd normally expect."

NASA's $19.9 billion budget proposal includes $10.5 billion for human exploration, with a focus on returning to the moon as a steppingstone for a trip to Mars.

Last week at the U.S. House Science, Space and Technology Committee meeting to discuss the budget proposal, members expressed their frustrations at the Senate's inability to confirm Bridenstine.

"In the environment we work in, the resources that the agency needs in the long term, having a director nominated and confirmed by the United States Senate from the administration is critically important," said Rep. Frank Lucas, a Republican from Oklahoma.

At that meeting, Lightfoot said he had no trouble accessing the White House, but that it would be valuable to have the president's choice holding the top position. Lightfoot at that time gave no indication that he would be leaving.

Lightfoot's career with the agency started in 1989 as a test engineer working on the space shuttle program, but it is not clear what his next move will be.

"I look forward to more time with my family and closest friends, and cheering the NASA team on from the outside," he wrote in his memo.

Lightfoot's announcement comes just a few months after Ellen Ochoa, director of Houston's Johnson Space Center, announced that she would retire in May.

Ochoa, the first Hispanic woman to go into space, logged more than 1,000 hours in orbit.

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