The reasons that do not allow electric space rockets to exist today

@ElentirENG ES 11·15·2023 · 5:42 0

Nowadays there is a tendency to replace cars powered by combustion engines with electric cars, with autonomy problems.

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In 2015, following an episode of The Simpsons, a controversy arose about the fact that Elon Musk is the owner of Tesla Motors, a well-known brand that manufactures electric cars and has notably promoted this type of vehicles, and yet their space company is based on rockets powered by liquid fuels.

Musk posted a Twitter thread in which he said: "If u saw @TheSimpsons and wonder why @SpaceX doesn't use an electric rocket to reach orbit, it is cuz that is impossible." Musk added: "Reason is Newton's Third Law. In vacuum, there is nothing to "push" against. You must react against ejected mass. AAnd pls don't ask me about space elevators until someone at least builds a carbon nanotube structure longer than a footbridge."

About the ion thruster alternative (used in ESA's ESA-JAXA BepiColombo mission, as we saw recently), Musk commented: "Ion thrusters are great, but have extremely tiny force (photon thruster even less). Must have more thrust than weight or you don't go up." It's This is why ion engines are used for space propulsion (that is, the movement of ships once in space), but currently lack the power to power a launch from Earth.

Regarding the railgun alternative, Musk commented: "anything launched by a railgun (if you could ever reach ~ Mach 27) would explode upon exiting the barrel in our dense atmosphere."

On these issues, the Spanish aerospace engineer Sergio Hidalgo has published an interesting videoin which he explains the challenges that an electric rocket should face and the reasons why it is technically impossible today (the video is in Spanish, you can activate the automatic English subtitles in the bottom bar of the player):

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Main photo: NASA/Tony Gray y Tim Terry. A SpaceX Falcon 9 rocket launch from Cape Canaveral, Florida, on March 6, 2020.