Although Kosmos 2612 is now backing away, the maneuver raised alarm bells for analysts who see it as part of a pattern of Russian aggression.

The mission, which launched on Monday, is headed to Phobos, the larger of the two moons of Mars. It could carry back the first samples from the Martian system.

Where did it start? How did it grow complex? Why did it get big? Three moments in Earth’s early history when evolution suddenly, inexplicably turned up the dial.