This Christmas season, astronauts aboard the International Space Station got into the holiday spirit by baking cookies for Santa in microgravity. Yet neither Santa nor the astronauts will be able to enjoy the baked cookies, since making them was part of a science experiment, designed to test a new oven on the orbital lab. Instead, the cookies will remain sealed and uneaten, only to be returned to Earth later on for analysis.

The cookies were made possible thanks to a newly developed space oven sent to the ISS in early November, aboard a Cygnus cargo spacecraft made by Northrop Grumman. The blue, cylindrical oven is the product of a New York-based startup called Zero G Kitchen and space technology developer Nanoracks, with ingredients provided by DoubleTree by Hilton.

The goal of the seemingly cruel experiment was to see if baking in a space environment is even possible. Here on Earth, turning cookie dough into a finished cookie is pretty straightforward. You put the dough on a pan in an oven, while hot air within the oven rises and fans circulate the heat throughout the tiny space. This causes the heat to be evenly distributed all over the cookie, causing it to puff upward and outward. But in space, heating gets tricky. Hot air doesn’t “rise” like it does here on Earth, and there’s no guarantee your cookie will stay on that pan; instead, it might just float away.

The Zero G Oven, as it’s named, is designed to combat these problems. “It doesn’t just work like your oven on the ground,” Mary Murphy, senior internal payloads manager at Nanoracks, said during a press conference before the oven’s launch in November. “We actually have to pretty substantially change the design of the oven, from what you thought about to what it actually is.” To evenly heat the dough within, the oven is shaped like a cylinder with heaters lining every side; that way, the cookie is heated evenly all over. And to make sure the cookie doesn’t float away within the oven, the dough must be loaded in via a special tray that traps the ingredients inside a tight pouch.

Luca Parmitano, an astronaut with the European Space Agency, tried baking samples on December 12th, 13th, and 17th with some success. “The oven is very, very simple to use, and I think it worked as expected,” Parmitano said in a statement provided by NASA. “We were able to bake the samples, but it took a few attempts to figure out how long they had to stay in the oven.”

Parmitano said the first three cookies he tried to bake came out pretty doughy, but the last two were nice and brown, with melted chocolate chips. “The samples are now stored in a freezer to be returned to the Earth for analysis. We’ll see how well it worked!” he said.

Since this is all very experimental, the researchers didn’t want the astronauts eating any improperly baked cookies, which is why the astronauts only get to pose for pictures with their treat. The samples will head back to Earth on an upcoming cargo trip home so that researchers on the ground can get a better look at the finished products. But ultimately, the idea of having the astronauts bake cookies they can’t eat is to see if it’s possible to have such small comforts of home when people go on multi-year trips to deep-space destinations in the future.

“What are we going to do when we’re in those experiences, and what are we going to need for those people to have a good experience and to be able to perform all these tasks that we’re going to ask of them to do all this amazing science research,” said Murphy. “So one of the things that that came to us as an opportunity was looking at baking in space.”

But don’t fear for the astronauts’ appetites. DoubleTree sent up a few pre-baked cookies to the station along with the raw dough, in case making the treats triggered some sugar cravings.