Astronauts Scott Kelly and Kjell Lindgren have completed the scheduled spacewalk outside the International Space Station (ISS) on Wedneday. The extravehicular activity (EVA) lasted seven hours and 16 minutes.

The spacewalk's main missions include lubricating the snare mechanism of one robotic arm of the lab, installing insulation on a physics experiment and laying out the power and data cables for a planned, new docking mechanism.

"The thought of getting into this miniature spaceship and going outside is incredible," said Lindgren.

The EVA is not without its challenges, however. Basic handyman work on Earth is already a chore, but in space, it becomes an entirely different and more dangerous scenario. Space debris can easily damage the ISS to a critical state. Exposure to fire and toxic elements are also a consideration, and the fact that medical help is not as easy to find in space as it is on Earth.

Last 2013, for example, an astronaut nearly drowned in his own spacesuit during an EVA.

"Imagine you're in a fish bowl," said David Korth, NASA's lead spacewalk flight director regarding the incident. "Go stick your head in a fish bowl and try to walk around, and that's not anything you would take lightly. And certainly, (spacewalking) is dangerous already."

Kelly and Lindgren have certainly taken every precaution they could and had practiced in full-scale mock setups to prepare for such dangers. Their spacesuits needed days of preparation to make them fit for the journey and to minimize malfunctions that could put the team in danger.

Being the senior astronaut, Kelly took the lead for this mission but NASA assigned Lindgren with some of the more difficult jobs in the repairs because he "has longer arms," which are apt in working in their limited space.