Upgrade Modules increase the scan radius, as well as providing very significant boosts to units earned per scan.
One of the first things you should aim to get for one of your multi-tools are some upgrades for your scanner.
When scanning Flora, Fauna, and Minerals in game, you receive units for a completed scan.
You can also earn nanites for uploading them from the Discovery menu.
The amount you earn per scan can be drastically improved by installing scanner upgrade modules.
Each module can add up to a 9999% bonus to those scans for flora, fauna or both.
With three S-class scanner upgrade modules, typical rewards for scanning flora is 60-75,000 units and 130-150,000 units for scanning common fauna. Uncommon fauna yields 1.5 as much, rare fauna -3 times as much.
As a result, each planet thoroughly scanned can bring 1-3M units.