Spacewalk-EVA

Spacewalk-EVA

Any time an astronaut gets out of a space vehicle, it is called an extravehicular activity, or EVA. This is also called a spacewalk.

History 

Russian astronaut Alexei Leonov performed the first spacewalk on March 18, 1965. The first spacewalk was 10 minutes long.

Astronaut Ed White performed the first American spacewalk during the Gemini 4 mission on June 3, 1965. White’s spacewalk lasted 23 minutes.

Spacewalk Record

The world record for the most spacewalks is held by Russian cosmonaut Anatoly Solovyev. He made 16 spacewalks for a total of more than 82 hours outside in space. 

Four NASA astronauts are tied most spacewalks. Michael Lopez-Alegria (Mike L.A.), Peggy Whitson, Bob Behnken and Chris Cassidy have each spacewalked 10 times. Mike L.A. holds the U.S. record for most time spent spacewalking. His total is more than 67 hours.

Why Astronauts Go on Spacewalks?

Astronauts go on spacewalks for many reasons. 

Spacewalks allow astronauts to work outside their spacecraft while still in space. One job astronauts do on a spacewalk is science experiments. Experiments can be attached to the outside of a spacecraft to see how the space environment affects different things. Astronauts place the experiments outside their spacecraft during a spacewalk. They go back outside to get the experiments when the tests are over.

Astronauts also can test new equipment and make repairs to satellites or to their spacecraft while in orbit. By going on spacewalks, astronauts can repair equipment that might otherwise have to be brought back to Earth for repair.

Astronauts aid on Spacewalks?

When astronauts go on spacewalks, they wear spacesuits. Spacesuits protect spacewalkers from the harsh environment of space. They protect astronauts from extreme hot and cold temperatures, harmful space dust and radiation. Spacesuits also give astronauts oxygen to breathe and water to drink during spacewalks.

Astronauts use handrails on the space station to help them move from place to place. Sometimes a large robotic arm is used to move astronauts on spacewalks. Astronauts are attached to the robotic arm using a foot restraint.

How Do Astronauts Stay Safe During Spacewalks?

When on a spacewalk, astronauts use safety tethers to attach themselves to their spacecraft. Tethers are like ropes. One end is attached to the spacewalker. The other end is connected to the vehicle. The safety tethers keep astronauts from floating away into space. Astronauts also use tethers to keep tools from floating away. They tether their tools to their spacesuits.

Another way astronauts stay safe during spacewalks is by wearing a SAFER. SAFER stands for Simplified Aid for EVA Rescue. SAFER is worn like a backpack. It uses small jet thrusters to let an astronaut move around in space. If an astronaut were to become untethered and float away, SAFER would help him or her fly back to the spacecraft. Astronauts control SAFER with a small joystick.

Astronauts Training for Spacewalks?

One way astronauts train for spacewalks is by going for a swim. Floating in space is a lot like floating in water. Astronauts practice spacewalks underwater in a large swimming pool near NASA’s Johnson Space Center in Houston, Texas.The pool is called the Neutral Buoyancy Laboratory, or NBL. It holds 6.2 million gallons of water. 

Another way astronauts practice for a spacewalk is by using virtual reality. Astronauts wear a helmet with a video screen inside and special gloves. A video of the simulation is shown on the screen inside the helmet. The special gloves allow astronauts’ movements to be shown with the video. The virtual reality simulation looks and feels just like a spacewalk.

Spacewalk challenges/accidents

1 Water Leak in Astronaut’s Suit

Luca Parmitano's Spacewalk (2013):

During a spacewalk, a leak in the spacesuit's cooling system caused water to accumulate in his helmet, forcing a premature end to the mission. 

Though it might seem like the solution to Parmitano’s problem was obvious, alas, the water was not from a drinking bag but from a leak in a liquid coolant system and would not have been the safest thing to drink.

2 Coughing Water into Helmet (2000 and 2001):

Astronauts Carlos Noriega and Chris Hadfield both experienced temporary vision impairment due to coughing water into their helmet visors. 

3. Eugene Trageser's Spacewalk (1965):

Trageser's protective pants, intended to shield him from heat, began to heat up instead, making his suit feel like a "hot bath". 

4.  Alexei Leonov, faced challenges like his suit ballooning when outside the spacecraft, preventing him from re-entering the airlock.

Compiled by

Ms Naresh kuwar