Search ARC Probes, Couriers and Assessors

285.8 per section looted One, two, and three stars: 4, 7, and 11.

Any map except Stella Montis. Each searched section scores on its own.
Prospecting Probes brings more Probes, and each one has three sections. Breaching one alerts nearby ARC, and that condition also adds drones.
Electromagnetic Storm brings more crashed Probes and Couriers, with one section each. The wiki calls that the fast way to three stars.
Assessors spawn only during Close Scrutiny, and the map marks them. The wiki calls that the easier three-star path.