Why Astronaut Trio Is Taking a Longer Path to the International Space Station

— -- You could say they're taking the long way there.

NASA's Kate Rubins and her two crewmates, Anatoly Ivanishin of Russia and Takuya Onishi of Japan, took off for the International Space Station Wednesday night on a cosmic road trip.

The most direct route to the International Space Station takes six hours, about the same time it takes to fly from New York to San Francisco. But the three astronauts, who launched from the Baikonur Cosmodrome in Kazakhstan, will spend two days — and 34 orbits of Earth — testing new systems before docking at the ISS.

They are traveling in an upgraded but still cramped Soyuz spacecraft and are due to arrive at the station at 12:12 a.m. Eastern time Saturday, July 9, where they will be greeted by their three other Expedition 48 colleagues.

At the ISS, the group will spend four months conducting "more than 250 science investigations in fields such as biology, Earth science, human research, physical sciences and technology development," according to NASA.

Rubins, a microbiologist, will stay at the space station until October.

"I think it's going to be amazing to see how the world of microbiology, molecular and cellular biology and human physiology is massively changed by microgravity," she told ABC News before her launch.

"This is the only laboratory we have as humans to study gravity as a variable," she said. "There's a world of insights to be gained into human health and disease by understanding how gravity and space radiation influence biology."