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A University of Canterbury chemistry academic is in the top one percent of applicants shortlisted by NASA to become an astronaut.

Dr Sarah Kessans is a postdoctoral fellow at the university.

Dr Kessans said she's absolutely humbled to have made it to this stage.

"Ecstatic, and honoured, and just a lot of different feelings, but definitely very excited."

Dr Kessans said she dreamed of becoming an astronaut when she was younger, but never thought it could be an actual career option for her.

She applied to be an astronaut in February but recently made the next cut for NASA's Astronaut Candidate Class of 2017.

Dr Kessans is one of about 120 invited to Houston, Texas for initial interviews later this month.

From there, 50 applicants will be invited for finalist interviews.

Up to 14 will then be chosen as NASA's 22nd Astronaut Candidate Class, reporting for duty in August next year.

Dr Kessans earned her PhD in 2011 from Arizona State University, where she worked to develop a plant-based vaccine against HIV.

Arriving in New Zealand in 2012, she has spent the last few years in UC's School of Biological Sciences with Renwick Dobson, gaining biochemistry experience in enzyme evolution and characterisation.

She has already proven herself capable of difficult and dangerous adventures, having been part of a team that rowed across the Atlantic in 2008.