If you're hanging from monkey bars and you let go, what happens? You fall to the ground thanks to gravity. What would happen if you were on those same monkey bars in space and let go? You would just float in space. Getting over the physical fear of falling is just one of the many challenges astronauts face while they are on spacewalks. 

Extreme temperatures are another challenge. 

"When you're in the sun it's about plus 100 to 250 degrees, so it's really hot," said astronaut Randy "Komrade" Bresnik.  "But as soon as that equipment goes into the shade ... it goes to minus 250 degrees."

This week Komrade Bresnik, along with Mark Vande Hei, will be conducting a spacewalk to replace a Latching End Effector (LEE) on the tip of the Canadarm2 robotic arm.

In the latest episode of ISS Science, Bresnik explains some of the challenges astronauts face during spacewalks, including extreme temperatures. Then, we simulate the effects of extreme temperatures on metals here on Earth.