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.