Reply To: Iconography

[Jan Hemmer]

Andrew Palfreyman wrote: There exists a generic problem with all propellantless schemes, and that is violation of both momentum and energy conservation. This leads to the generally true statement that if you can build a propellantless thruster, then you can generate free energy continuously, forever. Mathematically, all that’s required is to define a relationship between power input and thrust (you can pick linear or anything else you like). Then write down the energy budget for acceleration in free space, and compare kinetic energy to total input energy. You’ll find there’s a breakeven velocity (or equivalently distance or time), above which the kinetic energy exceeds the total input energy. So not only is a propellantless drive great for space travel, it solves all our energy problems too!

At first sight I would say the same reasoning goes for a conventional rocket.