Here's what history has to say about when Trump's NASA administrator will take office

On Friday, January 20, at 12:00 p.m. EST, Charles Bolden will resign as NASA administrator.

He was appointed by President Obama in May 2009 and confirmed by the Senate that July. Bolden didn't publicly express any desire to stay aboard for a Donald Trump presidency; nor has he apparently been asked to stay. Therefore, as is customary, he will leave office the moment the next president is sworn in.

NASA associate administrator Robert Lightfoot, who is currently the agency's highest-ranking civil servant, will become acting administrator after Bolden's departure.

How long will Lightfoot serve before a new administrator takes office? It's impossible to say, but if history serves as a guide, it could be a while before a new boss takes the helm. 

When John F. Kennedy became president in 1961, Hugh Dryden only served as acting administrator for 24 days until Kennedy appointed James Webb to run the agency. The duration acting and previous administrators have spent in office at the start of a president's first term has been creeping up ever since, culminating with Christopher Scolese, who served President Obama for 176 days before Bolden took office.

There have been 10 presidents in office since Dwight Eisenhower, who oversaw the creation of NASA in 1958.

Seven of those presidents started their first term with a previous NASA administrator still at the helm. Three presidents kept those holdover administrators on for an entire presidency. James Fletcher, a Nixon appointee, stayed for Ford, and Daniel Goldin, a George H. W. Bush appointee, stayed for Clinton. James Webb, a Kennedy appointee, stayed for all but three months of Lyndon Johnson's term.

That leaves just three clean-break presidential transitions where a new acting NASA administrator took over on day one; Lightfoot's tenure will mark the fourth. The other three were Hugh Dryden for Kennedy, Alan Lovelace for Reagan, and Christopher Scolese for Obama. 

Trump's choice for NASA administrator must be confirmed by the Senate. If either Trump or the Senate stalls, how might that affect NASA's long-term plans?

In part 3 of our Horizon Goal series, I described how the 176-day delay on Bolden's confirmation may have contributed to resistance the Obama administration encountered when it canceled George W. Bush's return-to-the-Moon Constellation program. 

The Congressional Budget Act requires the president to submit an annual federal budget request to Congress on or before the first Monday in February. The budget is a common place to introduce major program changes, and in Obama's case, it was the February 2010 budget that canceled Constellation. 

The independent review panel assigned to evaluate Constellation would have ideally been convened after Bolden took office. But after a few months of delays, the panel was finally commissioned in May 2009, just before Bolden's nomination. By the time Bolden took office, it was July, and the review panel's report wasn't issued until October.

That left just three-and-a-half months to orchestrate major program changes before the next budget release. Due to a political miscalculation, the short turnaround time, or some combination of both, the Obama administration did not corral widespread support prior to announcing Constellation's cancellation. The proposal was met with immediate backlash, culminating with the Congressional compromise that created the Space Launch System.

Therefore, if the Trump administration plans to introduce major NASA changes, it could be advantageous to get a new administrator in office sooner rather than later.

Charles Bolden leaves NASA after 2,744 days. The NASA administrator record holder is Daniel Goldin, who, in the course of 3,517 days, served both Bush administrations and the entirety of the Clinton presidency.

Bolden's stint as administrator is the third-longest in terms of consecutive days, and the fourth in terms of total days.