James E. D. Cline

Planetfall Twenty-seven James E. D. Cline

An early generation starship enters geostationary planetary orbit around a desolate but potentially habitable planet, and begins offloading its colonists bred for this colony. The colonists set loose nanomachines to crumble the basalt covering the planet, then discover a volcano-looking structure that looks too symmetrical to be natural. When the advancing nanomachines reach this pseudovolcano, it collapses; the colonists realize there is an alien species on the planet and first contact has not gone well.