The  Rebuttal: Debunking the Conspiracy Theorists
 2.4 Why were there no flames seen coming from the bottom of the ascent stage when it took off from the lunar surface to bring the astronauts back into orbit?
 
üThe reason is simple: the fuel-oxidizer mixture used for the ascent stage engine does not produce a visible flame.
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üThe hydrazine-dinitrogen tetraoxide mixture ignites on contact, affording products that are transparent.
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üIn fact, a very faint flame can sometimes be seen, but would not have been recorded by the crude video camera used.