CAPE CANAVERAL, Fla. (CBSDFW.COM/AP) — For the first time in 50 years, an astronaut-in-training is quitting NASA.

Astronaut candidate Robb Kulin has resigned halfway through his two years of training at Johnson Space Center in Houston. A NASA spokeswoman says his departure is effective Friday and that he is leaving for personal reasons that the space agency cannot discuss due to privacy laws.

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Astronaut candidate Robb Kulin has resigned halfway through his two years of training at Johnson Space Center in Houston. (photo credit: NASA)

Kulin, 34, was among 12 new astronauts chosen last summer from a record 18,300 applicants. An Alaskan native, Kulin was working as a senior manager at SpaceX when selected and said at the time he was hoping to fly on a vehicle he helped design. SpaceX and Boeing are developing NASA’s first commercial crew capsules, due to launch within the next year.

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The last time astronauts-in-training resigned from NASA was in 1968.

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Johnson Space Center is about 250 miles from DFW.