Today I am speaking to Manuel Schleiffelder, an aerospace engineer based in Vienna, Austria. Manuel has a background in designing and building experimental rockets with the student space team of the Technical University in Vienna, known as the Hound Project. I spoke to Manuel after he returned from a trip to the Black Rock Desert, where the Vienna space team tested their newest two-stage experimental rocket. Manuel has a very broad background in space engineering having worked on projects varying from spacecraft design of lunar landers and systems engineering of rocket propulsion systems, to his newest research project in materials science: metal matrix composites.
In a classic rocket engine the exhaust gases have a speed limit of exactly Mach 1 (the speed of sound) at the narrowest portion of the nozzle—the so-called choking condition. Since the speed of sound increases with temperature, hotter combustion means the exhaust gases can be expelled from the rocket at greater velocity. While the speed of sound in air at room temperature is typically around 1200 km/hr (745 mph), the speed of sound in the hot exhaust gases of a rocket can be more than 5 times this value. So even though we want our rocket engine to run as hot as possible, there are obvious practical limitations in terms of the ability of materials to withstand these extreme temperatures. For this reason, most rocket engines use some form of cooling to keep the material temperature within reasonable bounds. Manuel is currently developing metal matrix composite materials (carbon fibres embedded within a metal matrix) that are strong enough to withstand the extreme temperatures without the additional mass and complexity of a cooling system. In this episode, Manuel and I talk about
- his background in aerospace engineering
- the rockets that the Vienna student space team are building and testing
- and the advantages and challenges of developing metal matrix composites for rocket engines.
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