The 2017 NASA astronaut class
The 2017 NASA astronaut class; seventh from left: Robb KulinNASA/Robert Markowitz

For the first time in 50 years, one astronaut candidate recently left NASA's training midway through the course. As reported by AP, Robb Kulin, the candidate in question recently took the decision of leaving his training at the Space agency's Johnson Space Center in Houston. His termination will be effective on and from Friday.

According to the spokesperson of the American space agency, Brandi Dean, the reason as to why Kulin had to leave so abruptly is personal in nature and that's why it cannot be disclosed.

Before Kulin, it was in 1968 that an astronaut-in-training left the process in the middle without completing it. His name was John Llewellyn. Ars Technica reported that space historian and the editor of CollectSpace Robert Pearlman stated that Llewellyn had thought that he was not moving ahead fast enough towards the task of flying jet planes.

Kulin belongs to Anchorage, Alaska. He holds a master's degree in materials science and a doctorate degree in engineering. Previously he had worked as a senior manager for flight reliability at Elon Musk's SpaceX. NASA chose Robb Kulin out of the 18,300 applicants and he became one of the students at the space agency's class of 2017.

According to USA Today, NASA is not looking forward to replacing Kulin with some other applicant. The remaining 11 members of NASA's class of 2017 are still training to become astronauts.