Sports Illustrated is going big for its 50th anniversary. Other than having three cover girls this year, it also had Kate Upton pose in a bikini in zero gravity.

Esquire credits the idea to Jimmy Fallon, who last year told her that she should model in space. He joked, "think about this; there's no gravity." Upton graced the cover the last two years, which propelled her into stardom.

Sports Illustrated shared videos of the 21-year-old model in the zero gravity chamber, where she wore a gold bikini. She was told the most important thing was to face the camera. Business Insider said, "You could tell she was a little nervous for the crazy shoot that was about to happen."

The magazine partnered with Zero G, a tourism company that specializes in zero gravity. According to the Zero G, "weightlessness is achieved by doing aerobatic maneuvers known as parabolas." The plane reached 24,000 feet, and begins increasing the angle to 45 degrees and ultimately reaches 34,000 feet. The plane is then "pushed over" and the feeling of weightlessness happens for 20 to 30 seconds. This happens 12 to 15 times in an airspace of about 10 miles.

An SI editor said, "Kate surprised us all with how she handled modeling in weightlessness."

One thing is certain: Kate Upton will go to extremes for Sports Illustrated.

Last year she posed in Antarctica in a bikini. The magazine decided it wanted to shoot in all seven continents, and Upton went to the freezing continent in December.

MJ Daly told CNN a year ago that an Antarctica was their 'Hail Mary' attempt.

"It could have had a blizzard," Daly said. "Kate could have had shivering fits you could not shoot around. [Instead] we had six days of perfect weather."