Question: What do you use deep swimming pools to train astronauts?

Andrew Winnard answered on 5 Dec 2015:

Space agencies around the world use swimming pools to train astronauts and test equipment for working in weightlessness during space travel. When you go into water you float to the surface, unless you have some weights attached to you and then you sink. In neutral bouyancy we attach just enough weight so that you are balanced between floating to the surface and sinking. Once this is done you float in place without sinking or moving to the surface – this is called being neutrally bouyant. This is probably the closest you could get to experiencing weightlessness like space flight without lanching yourself into space for real. A parabolic flight is similar, but the weightlessness only lasts for around 20 seconds in the flights, where as in the pool, it lasts for as long as you need it to.

NASA has a pool which is 62m long, 31m wide and 12m deep. This is big enough to fit full size mock-ups of international space station modules. Astronauts learn how to do space walks using these mock-ups in the pool. This gives them a chance to try out their space suits, learn how to move around outside the space station and practice doing the jobs they will need to do in space.

A space walk at the International Space Station can last for five or more hours and astronauts usually traing about 40hours training in the pool across several classes for each space walk. This time is spent practicing the space walk, so astronauts can do it easily when they reach space. They also practice what to do in emergencies or if things go wrong. A couple of problems have come up in space walks before:

In the early days, we did not know that the space suit expands when you go out of the spaceship. In the vacuum of space there is no pressure to squeeze it flat. Way back in 1965 an astronaut on his first found he could not fit back in the door after a space walk and was stuck outside, running out of air! He eventually had to part deflate his suit just enough to squeeze back in.

If you were to let go of the space station and float away, you probably wouldn’t be able to get back. This could mean floating around Earth until your air runs out… In 1973 astronauts Pete Conrad and Joe Kerwin were thrown off an old space station called “Skylab” when they were hit by a solar array they were trying to fix. Luckily, astronauts all use safety tethers to fix themselves to the station and this is what saved Conrad and Kerwin.

More recently, one of the European astronauts, Luca Parmitano was blinded and choking from water leaking somwhere in his spacesuit and running into his helmet. The water covered his eyes, went in his ears and covered his nose. There was no way to wipe it or shake it free inside the space suit. He had to remember and feel his way back to the airlock very quickly where his crewmates quickly gothis helmet off. Luca was then fine afterwards.

So it is important to train for space walks so astronaut know how to do them and what to do in emergencies. This is why the swimming pools are important! When I worked at the astronaut centre I used to go swimming in the training pool for fun most weeks! This was just before Luca’s mission and he was often in the pool with us swimming to get fit before his launch.

It is very possible that Tim may get to do a space walk during his mission and you could watch it live! Here is a video of his training https://youtu.be/yr_mqfJomu8

Finally – if I win the launch zone, the money would be given to Blue Abyss! They are a company who are building the worlds deepest pool here in the UK. They plan to allow astronauts to train there and have a space research centre! They would run a virtual online classroom and teleconference for you guys to see and learn all about neutral bouyancy training.