On April 6, a giant research balloon lifted off in the Nevada desert. It carried a special payload: hundreds of miniature science experiments designed by students, nestled inside Ping-Pong balls for a journey to the edge of space. Twenty of these experiments, which are called PongSats, were created by Science World readers! They got a front-row seat on the balloon’s flight to about 19 kilometers (12 miles) up.

JP Aerospace, a volunteer-based California company that promotes affordable access to space, launches PongSats into the stratosphere. This atmospheric layer extends between 13 km (8 mi) and 50 km (30 mi) above Earth’s surface.

Science World teamed up with JP Aerospace for a special PongSat contest. In the Dec. 10, 2012, issue of Science World, we asked readers to design their own spacebound experiments. We received hundreds of entries from all over the country, and we selected 20 projects that stood out for their originality and clarity.

What did our winners send to space? Everything from a rubber band (to see if the stratosphere’s freezing temperatures change its stretchiness) to a wristwatch (to test whether the journey affects its ability to tell time). Others launched popcorn kernels, bubble wrap, and a USB flash drive.

The Science World experiments sat in a special rack on one of several balloons launched April 6. As the balloons ascended through the atmosphere, the helium inside them expanded. After floating into the stratosphere, the balloons popped, sending their payloads plummeting back to Earth. Then JP Aerospace’s recovery team tracked them down wherever they landed. One balloon landed in the mountains and took four days to find!

The PongSats are now being returned to the students who designed them, so they can find out if their hypotheses were correct.

You can check out the list of contest winners below. To apply for a spot on a future PongSat mission, visit http://www.jpaerospace.com.