Chris Hadfield: An astronaut's life is one of preparation and simulation, and training and support on the ground, and anticipation and visualization, and very very seldom, almost never is an astronaut's life about flying in space.
Part of what you're going through mentally is the necessity to convince yourself that it's real. You're sitting on your back in something that looks just like your simulator. But today is the day that you're actually going to space. And so the engines on the Soyuz start lighting half a minute before it's generated enough thrust to leave the pad. So it's interesting to be sitting in a rocket ship and have the engines running, and not going anywhere. And that will go on for almost, well, over twenty seconds. So these engines will be pouring tremendous power, the vehicle will be shaking. We'll see the flames coming out of it. But it won't be going anywhere, just be sitting there patiently. And once all the technicians and all the admitting systems have determined that, yep, everything's healthy, then all the rocket engines will light, and this thing will have more thrust than weight, and it will start to leave the Earth.
[Voice from the launch control center: “Lift off. Lift off of the Soyuz TMA-05M”]
The physical sensation is one of vibration. So each seat is shaking, the vehicle is shaking. But as you pick up speed as the vehicle gets lighter and lighter and lighter, the acceleration gets more and more. So you get squished heavier and heavier and heavier. And it actually becomes a little bit hard to breathe. If you can imagine four of you sitting on your chest for every single breath that you want to take. And as the vehicle looses its booster rockets, of course there's a big change in the shifting force when we go from the second stage to the third stage. It's as if someone was pushing you crazy in the back, and then grabs you, and pull you back and slam you forward again, so this is making WHAM-WHAM like that as you go through staging, and gets accelerated forward. And you're watching the clock tickling. And as soon as you hit 8 minutes and 45 seconds...BANG! Engines shut off...and you're weightless. And it's just an amazing sequence that took you from sitting there, hyper aware of what life is about to give you to just under nine minutes later being weightless in orbit. It's quite a ride!