One cosmic-ray bit-flip nearly lobotomizes an LLM — space data centers beware
A tinkerer simulated low-Earth-orbit radiation by randomly flipping bits inside Qwen2.5-Coder-3B's weights in memory. Models degrade shockingly fast: after a handful of bit-flips, the coder's human-eval score collapses from 85% toward zero, and a single flipped exponent bit can wreck a 49-billion-bit model. The results argue that plans for spaceborne or radiation-exposed data centers need ECC and fault handling as a serious design constraint, not an afterthought.