When scanned, it produces data (often rare and very rare). To collect data, target it and centre it in your field of view. Your ship will scan it automatically, and you will receive data.
Finding Satellites Edit
To Find a satellite, you can orbit a planet between 6Mm - 10Mm, at 10% - 20% throttle and drop in to Encoded Emissions signal sources. They're usually at inhabited Earth-like planets. Check that the dark side of the planet has city lights.
Target a planet, get a decent orbit distance where your FSD max is 200km/s or more. For example at Earth it's a 7.5mm orbit. Then you can maintain the distance and fly around until a Unidentified Signal Source appears. With an Encoded Signal Source it's often a satellite. These can give data such as Specialized Legacy Firmware.