Derelicts can be explored by anyone over the a captain level of 10. You will require the following items before you can successfully begin exploration.
On your personal load out (Space suit icon the blue footer bar) you will need the following fitted.

A Space Suit and an Oxygen supply. These items can be purchased initially from a Sven or Boris store and later you can craft them if you have the schematics and blue prints.

Then you will need a Docking Collar. This is a special item and is a player crafted special. They come in three sizes Docking Collar – Small, medium and Universal.

You will require Explorer League Faction rank to fit anything past the initial Docking Collar – Small.

Lastly you will require a Derelict scanner. There are three of these. Each is capable of scanning for different classes of derelict. Initially you will want a Derelict System Scanner T1. This will scan for derelicts A1 to A10. This will then mean anything you locate you can dock with using your docking collar.

Later as you rank up with the Explorers League you can fit larger docking collars and upgrade your scanner to locate larger derelicts.