Astronauts conduct spacewalks to either fix or install a new instrument at the space station. Since the robotic arms of the space station cannot perform the entire job at the exterior of the space station, the crew aboard often have to leave their cabin for such tasks. However, before each spacewalk, the participating astronauts will have to prepare ahead of time for the success of the extravehicular activity (EVA). So how do astronauts participate in spacewalks? Continue reading to find out.
What is a Spacewalk?
A spacewalk is an extravehicular activity (EVA) in which astronauts leave their vehicle while exploring the weightless environment of space. On March 18, 1965, Alexi Leonov, a Russian Cosmonaut became the first human to ever conduct a spacewalk which lasted for about 10 minutes.
However, on June 3, 1964, NASA astronaut Ed White became the first American to go for a spacewalk during Gemini 4 mission and it lasted for about 23 minutes. Currently, astronauts aboard the International Space Station and Tiangong space station usually go on spacewalks outside the station and these modern spacewalks last between five and eight hours depending on the tasks the astronauts have to accomplish outside the station.
Russian cosmonaut Anatoly Solovyev held the world record for the most spacewalks. During his career, Solovyev participated in 16 spacewalks which equals more than 82 hours outside the space station.
Why do Astronauts go for spacewalks?
Astronauts don’t just participate in spacewalks for the fun of the activity. Hence, there must be crucial reasons why they participate in spacewalks. Astronauts can conduct several science experiments during a spacewalk. Scientists usually learn a lot from these experiments and determine how space affects the astronauts outside their stations.
Astronauts also conduct spacewalks to test new equipment, repair satellites or install new instruments. Instead, of the astronauts returning the spacecraft to Earth for proper maintenance, they conduct spacewalks in space to fix the damages.
How Do Astronauts Train for Spacewalks?
Astronauts don’t have to wait until they arrive in the weightless environment of space before they begin to train for spacewalks. In fact, training for spacewalks commences even before the astronauts travel to space. Any space agency hoping to send its astronauts for a spacewalk must train them in underwater pools first. Hence, astronauts train for spacewalks by going for a swim. Scientists have realized that floating in space is similar to floating in water.
Hence, astronauts train for spacewalks in underwater large swimming pools. NASA’s massive swimming pool for this training is called the Neutral Buoyancy Laboratory (NBL) and it is located near NASA’s Johnson Space Center in Houston, Texas. The American space agency built this pool to hold up to 6.2 million gallons of water. Astronauts usually train for about seven hours in the pool for every hour they will spend participating in a spacewalk in space.
Astronauts also train for a spacewalk by using virtual reality. The virtual reality is like playing a video game and the astronauts often put on a helmet with the video screen embedded inside. The crew also wears a special glove for proper assistance during the virtual reality training. Once the astronaut moves, the special gloves often allow the movements to be displayed on the video. The virtual reality simulation makes the astronauts feel like the spacewalk is real in space.
How Do Astronauts Go on Spacewalks?
Before astronauts leave the space station for a spacewalk, they usually wear spacesuits to keep them safe. The inside spacesuits have enough oxygen and enough drinking water to sustain the crew throughout the spacewalk. Astronauts that will participate in the spacewalk are mandated to put on their spacesuits several hours before the EVA.
The suits are pressurized as they are filled with oxygen. Since the suit is too complex to be worn by a single person, other astronauts aboard the station often assist the participating astronauts in wearing the spacesuit properly. Once the astronauts have dressed in their suits, they will have to breathe pure oxygen for a few hours to get rid of all the nitrogen in their bodies. If the participating astronauts ignore getting rid of the nitrogen, they might get gas bubbles in their bodies during the spacewalk.
Scientists revealed that these gas bubbles can make astronauts suffer pain in their shoulders, knees, elbows, and wrists. Astronauts identify these pains as the bends as they most affect joints where the body bends. After spending a few hours in the airlock region, the astronauts will leave through the airlock door and commence with the spacewalk. The airlock has two doors. Once the astronauts are inside the space vehicle, the airlock is airtight to prevent air from leaving the spacecraft.
Hence, the astronauts usually leave for the spacewalk through the first door and lock it tight behind them. They can then proceed to open the second airlock door without allowing air to get out of the spacecraft. Once they complete the spacewalk, the astronauts can return to the spacecraft through the airlock.
How Do Astronauts Stay Safe During Spacewalks?
During spacewalks, astronauts are mandated to use safety tethers to stay closer to their spacecraft and avoid floating away in space. Tethers used in space are like ropes and one end of it is hooked to the astronauts while the other end is connected to the space vehicle. Aside from protecting astronauts from floating away in space, the tethers also help the astronauts to keep their tools intact and prevent them from floating away.
However, astronauts have to tether their tools to their spacesuits. The spacewalkers also stay safe in space by putting on SAFER. SAFER stands for Simplified Aid for EVA Rescue and it is worn like a backpack. This technology takes advantage of small jet thrusters to move astronauts around in space.
Hence, if an astronaut eventually becomes untethered and floats away in space, the SAFER would help the person to fly back to the space vehicle. Astronauts are trained to regulate the SAFER with a small joystick. This implies that they will control the space vehicle like they were playing a video game.
What Happens After the Spacewalk?
Once astronauts complete their spacewalks, they return to the space vehicle through the airlock chamber. They will remove their spacesuits and join the rest of the crew for other activities.
Conducting spacewalks in space requires lots of planning and effort from space agencies. So far, many astronauts have participated in spacewalks to prove that it is safe for humans to do so. We should be expecting more spacewalks in space in the future.