Comment by api
14 hours ago
2.4% is not bad given how new this still is and how extreme the speeds and energies are.
Note that all the fatalities have been launch or landing related, not in space itself. Clawing out of this gravity well is tough. Make Earth a bit larger and you’d never get off it without something like NERVA or nuclear pulse Orion.
I wonder sometimes if that’s another thing to toss in the Fermi paradox bucket. Many rocky planets might be much more massive than Earth. On one with 3X our gravity a space program might never get going.
NERVA as envisioned had terrible thrust to weight ratio, not really usable to launch from a Super Earth. Nuclear lightbulb, orion or heck NSWR would likely work though. And bonus points for not having to think about landing systems for the return trip. ;-)
In that case aliens from a super Earth would be unable to get off it unless they decided to salt their biosphere with fissile waste. NERVA is at least contained if it works properly.
So no space program from a super Earth until they figure out not just fusion but compact high density fusion that could fly. You’d need stuff like in The Expanse, or at least in that rough ballpark.
Using fission is something they probably wouldn’t do unless they faced an existential reason forcing them to go to space, like deflecting an asteroid.
I think a launch loop would still work, even on a Super Earth:
https://en.wikipedia.org/wiki/Launch_loop
Or potentially beamed power for launch, so you don't kug a power source. But in any case, indeed much harder. :)
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The lack of plate tectonics is a much bigger obstacle on Super-Earths, then g.
Yeah the more I learn the more I buy the rare Earth explanation.
Life may not be that unusual but it might be mostly just goo: little extremophile type bacteria and maybe very tiny creepy crawlies living in deep seas, underground, in liquid mantles in ice moons, etc.
But to get stuff even as sophisticated as frogs and bunnies, let alone something that can try space flight, requires a place that is all of: big, stable, with abundant energy, with high enough metallicity, and in an environment well shielded from flares and impacts.
There may not be a lot of places like this.