RACHEL MARTIN, HOST:

Good morning. I'm Rachel Martin. Some precious cargo arrived back on Earth yesterday. A capsule landed in the Pacific with almost two tons of material from the International Space Station, including chocolate chip cookies. Astronauts bake them to test a zero-gravity oven. But for the sake of science, they weren't allowed to take a bite. There were also mice in the capsule. They'd been in orbit for a muscle experiment. No word on whether they asked for a glass of milk. Transcript provided by NPR, Copyright NPR.