4 thoughts on “It’s Only Rocket Science

  1. The multiplication signs are annoying. Honestly though, that’s pretty easy. The left hand side is the standard gravity equation, while the right hand side is the standard kinetic energy equation, but with what appears to be the escape velocity.

  2. I’ve had this one on our refrigerator since I picked it up in the KSC gift shop last fall. It took several of us (including a few real rocket scientists) a few minutes to figure out what it was supposed to be. Not only are the multiply (x) signs superfluous, but you can cancel ‘m’ (the spacecraft mass) from both sides. You’re left with the equation relating the escape velocity from a planet with gravitational parameter GM at radius R from its center. For earth, GM = 398,600.4418 km^3/s^2 and radius is 6378.145 km, so escape velocity from the surface is 11.18 km/s. It works by setting your kinetic energy V^/2 equal to the negative of the potential energy -GM/R so that at infinity both are zero. That takes escape velocity.

Leave a Reply to Phil Cancel reply