So You Wanna Be A NASA Astronaut? Pretty Unlikely.

More people than ever are hoping they have “The Right Stuff,” and more people than ever will be disappointed that they do not.

By the deadline on Thursday, more than 18,300 people had submitted their résumés in hopes of joining the next group of NASA astronauts. That includes 4,000 procrastinators who applied in the final 48 hours.

“It was certainly beyond our expectations,” said Anne Roemer, the NASA official in charge of the selection process.

It is close to three times the number who responded the last time NASA put out a call for astronauts, in 2011. That time around, after sifting through 6,100 candidates, NASA selected eight, an acceptance rate of 0.13 percent. You have a much better chance of getting into Princeton or M.I.T., which admit about 8 percent of applicants.

This time, the odds will be even lower. NASA will first toss out applicants who do not meet minimum requirements such as having a college degree in mathematics, science or engineering. Last time, that winnowed out 1,300.

Then actual people, mostly NASA astronauts and not some computer algorithm, will take a look at each and every one of the remaining applications.

Of those, about 400 to 600 will be deemed “most qualified” and have their references checked. A selection board will then invite about 120 people to the Johnson Space Center in Houston for interviews.

“We’ve never gotten 18,000 applications, so I don’t know if that number may need to move up this time,” Ms. Roemer said. “We’ll have to play that by ear as we start going through the applications.”

NASA plans to announce eight to 14 new astronauts about halfway through 2017.

The previous record for the number of astronaut applications was 8,000 in 1978 when the space shuttle program was gearing up for its first launch.

At present, NASA’s human presence in space is modest — a couple of astronauts going in circles around Earth on the International Space Station. But NASA has been exuberantly proclaiming that it will send astronauts to Mars in two decades or so, although that is currently more aspirational than actual.

Still, that is a dream strong enough to attract people hoping to travel far, far away.