CAPE CANAVERAL, Fla. (AP) — Kate Rubins applied to be an astronaut while she was procrastinating about writing a grant application to the National Institutes of Health.

So on Tuesday, from orbit, she thanked the director of the NIH for her career.

Rubins, an infectious disease specialist who is the first virus hunter in space, was chosen by NASA in 2009. That's the same year Dr. Francis Collins took over the NIH after years of leading its National Human Genome Research Institute.

"So I think I would say probably 'Thank You' directly," Rubins said, laughing during a video hookup from the International Space Station, "because I have found myself in some extraordinary and unexpected places, because I have done whatever seems to be the most fascinating, interesting and compelling thing to do at that time."

Replied Collins, "I love that answer."

In August, Rubins became the first person in space to perform full-blown DNA decoding, or sequencing, using just a pocket-size device. She's already sequenced more than 1 billion base pairs, which are the building blocks of DNA. That's roughly one-third of a human genome, Collins pointed out.

The tests have been successful, Rubins noted, and show the value in the procedure for future space explorers and even those seeking life beyond Earth.

Collins said Rubins' outlook would benefit any young person pondering careers.

"A lot of it is keeping yourself open to unexpected opportunities — it sounds like being an astronaut was one of those for you — and not expect that you can actually plan things out over many decades" he said. "Things are changing too fast. There are too many exciting things happening in science.

"If you have a passion to make a discovery, to make a difference in the world, to add to the knowledge of the universe, science is a great place to be right now."

Rubins showed Collins one of the large laboratory pipettes — droppers for liquid samples — she took up to test in weightlessness. To her surprise, they worked just as well as on Earth.

"That was not my hypothesis," she said.

That's how she spent her spare time, she confessed.

Rubins, 38, has a Ph.D. in cancer biology. Before joining NASA, she worked with some of the world's deadliest viruses, including Ebola, and conducted research in Congo. Her space samples, for the DNA testing, were harmless.

Her four-month mission ends in just over a week, with a return to Earth aboard a Russian Soyuz spacecraft.