In the early 1980s, the Pioneer 10 and 11 spacecraft were hurtling toward the edge of the solar system when scientists noticed something terrifying. The probes were slowing down. The deceleration was microscopic, but it violated everything humanity understood about physics. For decades, the "Pioneer Anomaly" threw astrophysics into a state of panic. Had we misunderstood Newtonian gravity? Was dark matter pulling the ships backward? The anomaly was so persistent that it threatened to dismantle the foundational equations that governed the universe. The truth, discovered nearly thirty years later, was a masterclass in chaotic engineering. The deceleration was not caused by mysterious cosmic forces, but by the probes' own internal nuclear batteries. Uneven thermal radiation was bouncing off the ship's antenna, acting like a tiny, continuous thruster pushing against the void. This book explores the intense forensic science required to solve a mystery billions of miles away. Understand how rigorous data analysis saved the laws of physics from the brink of collapse.