Assemblers of Infinity by Kevin J Anderson
Approx. 116,150 words.
Published on November 26, 2010 by
Nebula Award Nominee. The crew of Moonbase Columbus make an amazing discovery on the far side of the Moon—a massive alien structure is erecting itself, built up atom by atom by living machines, microscopically small, intelligent, and unstoppable, consuming everything they touch. The mysterious structure begins to expand and take shape, and its creators begin to multiply.