"In April, I discovered vacuum for the first time. I tested the EMU spacesuit in spatial conditions inside a vacuum chamber at the Johnson Space Flight Center (Houston).

The aim was to get familiarized with some of the American spacesuit devices that I can not test during the pool simulations. For example the two small valves that blow some air to the outside and thus create a small air circulation within the suit - it is sometimes necessary when it is too hot inside. Or the connection by "umbilical cord" with the station, which provides the spacesuit oxygen and electrical power during the time we spend in the airlock before and after a spacewalk.

The preparation before a spacewalk is very long. We must carefully check the spacesuit, which takes about two hours, and then, in the airlock, we must patiently wait during the decompression phases, before going out into the void, which is even longer! In the space station, the ambient pressure is of one atmosphere. And air, as on Earth, is composed of nitrogen first and then oxygen. In the suit, the pressure is not more than 0.4 atmosphere, but it is pure oxygen. The role of the decompression phases is to slowly purge our bloodstream of its nitrogen, simply by breathing. If we would quickly decrease the pressure inside the spacesuit, nitrogen would dissolved in our blood and could make bubbles!

Throughout this phase, my spacesuit was suspended from the ceiling (yes, it is 150 kg on Earth so it is impossible to wear it!), So I watched a movie to pass the time: The Marsian, with Matt Damon. When I finally reached 0.4 atmosphere of pressure, with the vacuum outside the suit, nothing had changed ... except my voice! Yes: vocal cord vibrations do not produce the same sound in a rarefied atmosphere.

To realize that I was in the void, I made two experiences. The first simply consisted of observing a glass of water next to me in the vacuum chamber. I could see that the water was boiling at 17 °C only, room temperature. It was very strange. The second experience was even more spectacular. I had a ball of lead and a feather that I dropped at the same time: they fell at the same speed! As understood Galileo and Newton, it is the air that slows feather in its fall.

When I will be in orbit, I will also have the opportunity to do some fun experiences. But I won’t take feathers and lead balls ,which, in space, is of no use!

To realize that I was in the void
Thomas Pesquet

My bags are already prepared. In the jargon of NASA, we call them CTB for Crew Transfer Bag. I am entitled to take one CTB, which represents a little more than the size of a carryon luggage in an airplane cabin. My CTB consists of a 'communication' kit and a personal business kit. Inside, there are dolls, T-shirts, patches, related to the ESA communication around the mission, a French flag, symbols of Normandy and Rouen, where I come from. I will take with me the signed agreement of the COP21 that I received from the president, the complete editions of Saint-Exupéry in the Pleiades, because it is an author I've read a lot and I will reread in orbit. I will of course take "From the Earth to the Moon" by Jules Verne. And I will also carry symbolic objects that have a lot of meaning for me: my black belt in judo, my Air France pilot badge, a polo ‘Supaéro’, my A320 model, and a t-shirt San Antonio Spurs (a nod to Tony Parker). There will also be some surprises, sports-related, and I will carry enough to make a few jokes at my promo fellow ESA astronauts, the Shenanigans. It's a tradition that we must not lose!

Everything I just mentioned, and many other more personal things such as many family photos, have already been sent to the United States. These "suitcases" will fly to the space station before the crew aboard an automatic cargo. I can bring one and a half kilos of baggage that I will carry with me in the Soyuz. I'll take some jewelry for my wife, a watch for my brother, maybe for me, a Martian meteorite fragment that I got at the Space City, and other things that I do not have yet chosen. Until the end, the choice will be difficult: a kilo and a half, it is not heavy!"

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