— The countdown is now on for an unprecedented commercial spaceflight and you can help decide one of the key factors — or rather, flavors — of the launch.

7-Eleven, the largest and oldest chain of convenience stores, is sending its iconic Slurpee drink "on a private spaceflight" in celebration of its 94th year in business. The frozen beverage is set to leave Earth this August on a balloon-lofted flight into the stratosphere, departing from a 7-Eleven store in Michigan, the "Slurpee capital of the U.S." (a.k.a. the state that consumes the most Slurpee drinks).

"In the spirit of Taking it to Eleven for our birthday month, we're delivering our beloved Slurpee to space and bringing our customers along for the journey," said Marissa Jarratt, 7-Eleven's senior vice president and chief marketing officer. "After all, what is more far out than outer space?"

With the launch site selected and the logistics set, all that remains is to pick what flavor will make history as the first Slurpee in "space."

"Will it be Cosmic Coca-Cola or Cherry, Big Bang Blue Raspberry, Planetary Peach Perfect or Galactic vitaminwater Zero Sugar Gutsy?" 7-Eleven posed in its press release.

The chain is leaving that choice to its customers. The most popular Slurpee flavor that is ordered using the 7-Eleven app for 7-Eleven Delivery through the end of July will be used to fill the cups that are then sent spaceward.

And they just won't be just any cups: 7-Eleven has produced a limited number of commemorative Slurpee cups featuring the "Slurpee Space Delivery" logo on their front and a take on the Apollo lunar lander plaques on their back, declaring it as a "Slurpee For All Mankind."

Once back on Earth, 7-Eleven will give away the cups to some of the same people who helped pick the high-flying flavor. With each 7-Eleven Delivery order through the month of July, 7-Eleven app users will be entered in a chance to win one of the exclusive cups as a "Slurpee in Space" memento.

Ten stainless steel tumblers and 30 plastic cups will make the stratospheric trip and be given away through the contest.

The promotion is open to U.S. residents who are of 13 years of age or older. You can also enter without making a purchase by mailing a 3 by 5-inch card with your name, mailing address and email address to: Creative Zing / Slurpee Into Space Sweepstakes, PO Box 607807, Orlando, FL 32860. See 7-Eleven's website for the complete rules for the sweepstakes.

Announced on Monday (July 12), the news of 7-Eleven's Slurpee spaceflight came just a day after Virgin Galactic launched its founder, Richard Branson, on the company's first fully-crewed suborbital test flight. Branson flew on July 11, or 7-11.

"Today is MY DAY, ugh," 7-Eleven wrote on Twitter, reacting to Branson's triumph. "Tired: sending man to space. Inspired: delivering Slurpee to space."