Cité de l'Espace

Ariane 5 rocket

During my last visit to France, I visited the Cité de l'Espace in Toulouse, space capital of Europe. The Cité de l'Espace (City of Space) is the european equivalent of the Kenedy Space Center's visitor complex. In addition to numerous interactive exhibits revolving around space exploration, they have a bunch of real space hardware on display, including a Soyuz spaceship and a mockup of the Russian Mir space station that was once used to train astronauts.

Looking at all this hardware reminded me of how complicated space travel is. It really is rocket science... For example there was a Vulcain rocket engine on display, with various parts cut-out so that we could see the inside. Check out the complexity of the gas turbine and fuel turbo-pump assembly:

Vulcain engine turbo-pump

The turbo-pump takes fuel from the tanks and injects it at high pressure into the combustion chamber. The pressure in the combustion chamber is extremely high since this is where the fuel explodes (the resulting reaction produces the rocket engine's thrust). So the turbo-pump must compress the fuel at an even higher pressure if it wants to inject it into the combustion chamber. In order to achieve that, a turbo-machine (similar to a jet engine) that runs on rocket fuel is used to power the turbo-pump. The pump rotates at 34,000 rpm and injects 320 kg of liquid hydrogen per second, at a pressure of 115 bars (~115 times the atmospheric pressure).

Other side of Vulcain engine

Another example of complexity in something that would otherwise seem pretty trivial is the mechanism that separates two rocket stages. A series a little explosive charges situated all around the rim of the top of the stage explode and inflate little rubber bags that in turn pushes away the metal pincers that hold the two stages together (pictures below).

Soyuz spacecraft

Close-up of the Soyuz spacecraft, with the green periscope that enables the crew to see past the white living module.

Soyuz computer and electrical connectors

The Mir mock-up was the one used to train astronauts in one of those gigantic swimming pools in Baikonour. The modules themselves are not the real thing (those are made of thick steel, the real ones are made of thin aluminum) but all the equipment and accessories inside and outside are real (spare parts that were not flown).

Mir Space Station

Mir toilet...

...and shower

Those big black balls on top of the Mir station are gyrodynes, or gyro-stabilysers used to control the space station's orientation. They are heavy balls that are rotated are 10,000 rpm thus creating a momentum that makes it hard for anything to rotate the space station, hence the stabilizing effect (just like a fast rotating bicycle wheel is hard move on its axle). Mir had 11 of those.

 [www.cite-espace.com]