This year marks the 50th anniversary of the first space EVA (extra vehicular activity), or “spacewalk”. An EVA is when an astronaut wears a special space suit (called an EMU, Extravehicular Mobility Unit) and leaves the space station or shuttle to perform tasks in the outer space environment.

In March of 1965, cosmonaut Alexey Leonov left his Voskhod spacecraft with only a space suit protecting him from the vacuum of space. But, as with all historic firsts, the unexpected happened. His space suit expanded during the EVA, and he was forced to open a valve in the suit to decrease the pressure inside and almost didn’t make it back inside the spacecraft. This amazing feat of human bravery and ingenuity paved the way for future space walks – including the repair of the Hubble space telescope and building the International Space Station (ISS). But one of the most renowned EVAs was the one that was marked with these famous words:

“That’s one small step for man, one giant leap for mankind.” – Neil Armstrong

In July of 1969, astronauts Neil Armstrong and Buzz Aldrin landed the Eagle lunar module on the surface of the Moon and became the first humans to perform an EVA on an alien surface. To this day, only six pairs of astronauts have performed EVAs on the Moon, the last in December of 1972.

The 1970’s became less about getting to Earth’s natural satellite, and more about creating artificial ones. In 1979, NASA set out to create its first space station – Skylab. However it was extremely damaged during the launch, half of its main solar panels tore away and the other half were jammed in place and could not open. This was considered a catastrophe at the time, but it opened up a whole new area of space exploration by forcing astronauts to quickly come up with solutions to make major repairs during an EVA.

In the early 1980’s the USSR’s Salyut-7 space station hosted the first woman in space, cosmonaut Svetlana Yevgenyevna. She would also be the first woman to perform an EVA as she repaired the outside of the space station.

In the mid-1980’s while Salyut-7 was crewless, all systems shut down and the space station began to drift. In what has been described as “one of the most impressive feats in-space repair history”, a crew, including Yevgenyevna, docked at the shutdown station using only handheld lasers to determine the distance necessary to match it’s rotation as it tumbled through space.

The Salyut-7 developed what they called “Heavy Cosmos modules,” the new Mir space station was able to become by far the largest artificial satellite in orbit by having modules attached while in space. Mir’s size and longevity were only surpassed by the International Space Station. The ISS was built using the same principles as Mir, by assembling interconnecting modules using EVAs.

EVA experience was used again in the ‘90s after the launch of NASAs Hubble Telescope. When Hubble sent back photos that were blurry it was discovered that the installed mirror was too flat by 2.2 micrometres. It was too expensive to bring Hubble back to Earth to repair so astronauts were sent on EVAs to repair the telescope and add components that would compensate for the microscopic error in curvature.

Hubble was designed to be regularly upgraded and was always intended to receive regular servicing, so astronauts were trained to use over a hundred specialised tools to do this. This year marks Hubble’s 25thanniversary of space exploration, and will provide stunning images of the depths of Space for years to come. The longevity of space technology has been dramatically increased all because of the thousands of hours from hundreds of scientists and engineers in crafting individual space suits for every person who ever left Earth’s atmosphere as an astronaut.