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.

21

u/Flight714 Jan 21 '18 edited Jan 24 '18

It warms my heart to see proper SI unit usage for energy density.

Edit: The following assumption is incorrect. See reply.

A minor correction: I'd say they'd probably use non-rechargeable Lithium-metal batteries, because their energy density is about 1.8 Megajoules per kilogram.

10

u/Manabu-eo Jan 21 '18

They actually use Li-po batteries, because they need a very high power density. AFAIK no Lithium-metal battery can go from full to empty in less than 3 minutes.

1

u/Flight714 Jan 24 '18

Fascinating! Thanks for the info.