As the title suggests, this module would provide protection against being scanned.
Scan shielding would not do anything to the ship's external signature, but it would prevent a ship scan from detecting what you are carrying. This protection would be based on range and time. Better protection would reduce the maximum range from which you could be successfully scanned, and increase the time it takes to complete the scan. Higher class scan shielding would mostly reduce range and higher grade scan shielding would mostly increase time.
The downside to scan shielding would not only be the space it takes, but it would have large mass as well (real scan shielding is usually made of dense and therefore heavy materials anyway).
Scan shielding would not do anything to the ship's external signature, but it would prevent a ship scan from detecting what you are carrying. This protection would be based on range and time. Better protection would reduce the maximum range from which you could be successfully scanned, and increase the time it takes to complete the scan. Higher class scan shielding would mostly reduce range and higher grade scan shielding would mostly increase time.
The downside to scan shielding would not only be the space it takes, but it would have large mass as well (real scan shielding is usually made of dense and therefore heavy materials anyway).