WASHINGTON — Despite a last-ditch campaign to keep Mike Griffin on as NASA administrator, the transition team of President-elect BarackObama was vetting replacement candidates the late during week of Jan. 5. At press time, however, no announcement had been made.

Charles Kennel, an environmental scientist who previously ran NASA’s Earth science enterprise, emerged late in the week as a possibility among a handful of candidates under consideration. But a source with ties to Obama’s NASA transition team downplayed that possibility Jan. 9. This source said the team had settled on a candidate but declined to identify the prospective nominee.

A decision is expected before Obama’s Jan. 20 inauguration, possibly sooner, and sources with ties to the NASA transition team said is not expected to be retained.

submitted his letter of resignation in December, along with all political appointees of the outgoing administration of President George W. Bush. In a Jan. 8 e-mail, said he had not yet been asked to stay.

“There’s no discussion unless the new team wants to have one. In the case of NASA, it is hard to imagine that the president-elect has time to deal with succession anytime prior to [Jan. 20], so in all likelihood the clock ticks over and I am gone,” he said.

Nick Shapiro, spokesman for the Obama transition team, declined to comment.

Griffin had said in recent weeks that he would like to stay on to finish work he had started on building NASA’s next generation of vehicles aimed at sending humans to the Moon and beyond.

A petition drive to keep Griffin launched by former NASA astronaut Scott “Doc” Horowitz and circulated to friends and colleagues by ‘s wife, Rebecca, left both honored and embarrassed, he said Jan. 8 in a speech at the Space Transportation Association breakfast on Capitol Hill.

Some members of Congress, including Rep. Bart Gordon (D-Tenn.), chairman of the House Science and Technology Committee with NASA oversight, and the committee’s ranking member, Rep. Ralph Hall (R-Texas), had recommended keeping Griffin in his post, at least through inauguration.

“He’s been really a staunch advocate for NASA – the agency, scientists, engineers and administrative staff. He’s given them and our nation, I think, a sense of pride,” Hall said in introducing during the Jan. 8 breakfast.

Sources close to the NASA transition effort, meanwhile, said Obama’s overall transition team co-chair, John Podesta, and his colleagues formally have begun vetting NASA administrator candidates.

One source with ties to the NASA transition team said the Obama administration would like to pick a distinguished scientist to lead NASA, noting that Obama already has tapped physicist John Holdren as his science adviser and Nobel laureate physicist Steven Chu to run the U.S. Department of Energy.

If the Obama administration is determined to put a scientist at NASA’s helm, that would disqualify retired U.S. Marine Corps Maj. Gen. Charles Bolden, a former space shuttle commander. Space News identified Bolden in November as a potential NASA administrator candidate and he has been the subject of fervent press speculation in recent days.

The source who identified Kennel as a serious contender for NASA’s top job cautioned that the Obama transition team, at least as of Jan. 8, had not settled on a candidate. The source said Podesta and his colleagues were considering names submitted by Obama’s NASA transition team as well as some names of their own. The source said it was possible that when Podesta goes to Obama with a recommendation, the president-elect “may have a name or two” to enter into the mix. Two sources said the Obama transition team also has reached out to Capitol Hill for input.

Other candidates said by sources to still be in the running include: Alan Stern, former NASA associate administrator for science and Scott Hubbard, former director of NASA’s

Bolden, meanwhile, said during a Jan. 6 webcast organized by the Conrad Foundation that he had not been approached by the Obama administration.

“I’m incredibly honored that my name would be floated around, but those are things I haven’t been approached about yet so I can’t offer you an opinion or anything,” Bolden said.