Kate Upton's Zero Gravity shoot for Sports Illustrated's 2014 swimsuit edition is out of this world. In space no one can hear you moan, but Kate's buoyant bikini bod is loud and clear.

Now we know what keeps Upton up, the 21-year-old supermodel hit the air floating in a bikini for her photo shoot with Zero Gravity Corp. ZERO-G for Sports Illustrated's 50th swimsuit issue.

The zero gravity shots show Upton floating in mid-air. The photo shoot was done back in spring 2013.

In a press release MJ Day, editor of the Sports Illustrated swimsuit issue, said  "The ZERO-G experience was really exhilarating for everyone involved. We have been almost everywhere in the past 50 years with SI Swimsuit, but we have never done anything like this. It was certainly the most out-of-the-box shoot. Once again, Kate surprised us all with how she handled modeling in weightlessness."

Kate Upton has been on the front page of Sports Illustrated's Swimsuit Issue for the past two years, now she's in the rear.

Besides the zero gravity shoot, Kate also modeled in quite a few bikinis for beach shots. Including a legends shoot with Tyra Banks.

Kate Upton took to Twitter to congratulate the other models in the issue, tweeting "OMG! So happy for @LilyAldridge @chrissteigen and @NinaAgdal!!" she wrote on Valentine's Day.

Supermodel Kate Upton has been called a "modern day Marilyn Monroe" going from Sports Illustrated covers to movies. Kate did a silver plated cameo in the film "Tower Heist" in 2011 and raised the temperatures of "The Three Stooges" in 2012. Kate Upton is currently starring with Cameron Diaz and Nicki Minaj in the romantic revenge comedy, "The Other Woman."