Part 5/11:
The Major Challenges: Energy and Propulsion
The Energy Dilemma
A primary limiting factor in interstellar travel is energy. Faster-than-light travel is impossible with current physics, so reaching even a significant fraction of light speed requires immense amounts of energy. Spacecraft engines need power comparable to or exceeding the energy output of entire planets or stars.
Current propulsion methods, like chemical rockets, are vastly insufficient for interstellar distances. The goal is to find alternative energy sources that can sustain high velocities without requiring infeasible fuel quantities. Light sails powered by lasers are promising, but they still need substantial advancements in energy efficiency and beam focusing.