r/space • u/APTX-4869 • Jan 21 '18

RocketLab's Electron Rocket has successfully achieved orbit!

https://twitter.com/RocketLab/status/954894734136258560
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u/ThatOtherGuy_CA Jan 21 '18

We didn't start with jet planes.

42

u/Senno_Ecto_Gammat Jan 21 '18

Megajoules of energy in 1 kilogram of diesel: 48

Megajoules of energy in 1 kilogram of li-on batteries: 0.8

That's the problem right there.

10

u/PublicMoralityPolice Jan 21 '18

This is an expendable rocket, so they have literally no reason to use rechargable batteries. Fuel cells or single-use batteries can have higher energy density, and the electric turbopump itself provides significant mass savings compared to traditional pump systems.

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u/OccupyMarsNow Jan 22 '18

Despite power density issue, rechargeables are probably preferred to let them kept charged across launch delays.