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A comment on Rocket Launch in New Zealand Brings Quick, Cheap Space Access. Parent comment

Re:Rocket Launch in New Zealand Brings Quick, Cheap Space Ac... by rocqua on Sunday November 11, 2018 @12:45PM (#18427525)
As I recall, it remains the case that rocket engines get worse performance with an electric fuel pump.

Electric has two issues. First of all, the energy density (after controlling for efficiency of electric motors / turbo pumps) is lower than that of rocket fuel. Second of all, an empty battery weighs as much as a full one, whereas used fuel no longer weighs down the rocket.

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Re:Rocket Launch in New Zealand Brings Quick, Cheap Space Ac... by wolf550e on Sunday November 11, 2018 @12:49PM (#18427548)
They disconnect and dump the battery mid-flight on ascent to not carry the mass of the empty battery, which might be counted as half a stage in rocket terminology (like https://en.wikipedia.org/wiki/SM-65_Atlas)

See: https://www.youtube.com/watch?v=sPwMuUxSrcA&t=1625

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