“Super-Earths in Need for Extremely Big Rockets”, 2018-03-30 ():
Many rocky exoplanets are heavier and larger than Earth, so-called “Super-Earths”. Some of these may be habitable, and a few may be inhabited by Super-Earthlings. Due to the higher surface gravity on these worlds, space-flight is much more challenging.
We find that chemical rockets still allow for escape velocities on Super-Earths up to 10× Earth mass. Much heavier rocky worlds, if they exist, will require using up most of the planet as chemical fuel for the (one) launch, a rather risky undertaking.
We also briefly discuss launching rockets from water worlds, which requires Alien megastructures.