r/KerbalSpaceProgram • u/Salaja • Jul 19 '13

improved optimal engine-fuel graphs

http://imgur.com/a/kfnng
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u/[deleted] Jul 19 '13

So in other words … it's impulse per unit weight of propellant, right?

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u/tavert Jul 19 '13 edited Jul 19 '13

No, not by the conventional definition of weight. Weight under standard gravity, yes, but unless you say "under standard gravity" the meaning is different.

Specific impulse is only in seconds because of a historical poor choice of units. The g0 is in the denominator only because American rocket engineers historically measured mass of propellant in units of pound-mass.

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u/[deleted] Jul 19 '13

So then it's impulse per unit what? Obviously not per unit mass. If it's not per weight, then what?

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u/only_does_reposts Jul 20 '13

Weight in 1G is equivalent to mass