The Future of Propellantless Space Travel

Every kilogram of rocket fuel is dead weight once it’s burned, yet conventional spacecraft must carry hundreds, sometimes thousands of tons of propellant to reach even nearby planets. This fundamental limitation has confined humanity to our own Solar System for decades. But a new generation of propulsion concepts promises to break free from this constraint entirely, harnessing radiation pressure, solar wind, and planetary gravity to accelerate spacecraft without carrying a single drop of fuel. These elegant systems could finally make interstellar exploration feasible…if engineers can overcome their formidable technical challenges.