The USS Discovery is a Rare Grade 3 Explorer whose signature trick is instant warp -- get it to a system fast, then use its Summoning ability to tear a hole in the Mycelial network and pull other ships to it instantly, regardless of their normal warp range. It works on any of your available ships: summon mining ships once their cargo is full, pull warships to wherever you need them, or build your own routine around it.
To unlock Summoning you need the USS Discovery itself plus the 'USS Discovery Summoning' research in the Galaxy Research tree. Once unlocked, it appears as a new button in the Discovery's ship action panel. A summoned ship arrives in whatever system the Discovery currently occupies, and the summoning cost is paid the moment the summoned ship begins its warp -- but only Available ships qualify. If it's not working, check that your Discovery isn't mid-combat, warping, repairing, or tiering up, that the target ship is in a different system and also Available, and that you have enough resources to cover both the Summoning cost and any Transwarp cell cost for the trip.