When you think about the risks an astronaut takes, you might imagine the launch, the lack of oxygen, and the cold vacuum of space. But there's another invisible danger that's arguably more deadly: radiation exposure. Space is teeming with high-energy particles that wreak havoc on living cells, and can cause everything from cataracts and reproductive damage to cancer and mutations in DNA. On Earth, we're protected from most of these particles by our planet's magnetic field, but in space, there's nowhere to hide.
Before the galaxy's creepiest astronaut came aboard, scientists had only been able to determine the dose of radiation to which ISS astronauts were exposed with one type of passive sensor, which measures total radiation. The Phantom Torso, on the other hand, was wired with both passive sensors and active sensors, which give real-time readings. Hundreds of sensors were placed at five different locations in the Phantom's body, including his brain, thyroid, heart, stomach, and colon, and still more were placed next to him to measure the radiation inside the spacecraft. There were around 350 sensors in all.