# Do spacecraft engines suffer from carbon accumulation the way typical petrol/kerosene engines do?

Just wondering whether the spacecraft engines/drives, or their booster rockets accumulate carbon the way car/truck engines do. What about ion/methane drives?

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Not typically. In fact, the opposite generally occurs. The high temperatures and velocities in the rocket motor tend to cause erosion (ablation) along the nozzle. There is considerable research into the ablation of the nozzles because it changes the shape and thus the thrust characteristics. See for example this paper, and a simple search will reveal many more.

It's also important to note that many spacecraft engines don't use carbon-based fuels. Solid rocket motors typically do, the binder material is usually a carbon-based material. But some liquid rocket engines are hydrogen and oxygen, so no carbon is involved.

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Nice answer, +1, but many rockets use LOX/RP-1 in their first stages. –  mmc Oct 18 '12 at 17:14
These reference rockets heading from Earth's surface upwards. Any idea about drives for manouvering in space itself? For instance, the rockets on the Apollo modules. –  Everyone Oct 18 '12 at 17:28
Apollo command modules and both the ascent and descent stages of the lunar modules ran on Aerozine 50 (N$_2$H$_2$/H$_2$NN(CH$_3$)$_2$) and nitrogen tetroxide (N$_2$O$_4$), which are not really hydrocarbons. They're also hypergolic: they react without a spark. –  Emilio Pisanty Oct 18 '12 at 18:06