Question

In our search for intelligent life on exoplanets, the feasibility of rocket technology must be
considered on other planets. In order to escape a planets gravity a rocket must attain escape
velocity. If a rocket is to attain this velocity, or at least have enough energy to attain this, then
this can be substituted in for v−v0 in Tsiolkovsky rocket equation. If the exhaust velocity from
the rocket is 4400 m/s, and we assume the maximum amount of propellant practical is 96% (4%
rocket) then estimate the size of a planet where rocket technology is impractical. Assume the
alien planet has the same density of earth. The mass and radius of earth is 5.972×1024 kg and
6.371×106 m, respectively.

Answer 1