This is for completing Cora's loyalty mission. I do not believe that this can become active until after you have settled Eos.
*** Spoiler - click to reveal ***
After doing so, and going back on board the Tempest, you will receive an email from Cora. Read it and speak to her on board the ship. She will tell you that she needs to speak to someone named Hydaria on Eos. Go there and speak with her. She will direct you to Voeld to find the ark Periphona. Go there and track the signal. When you find it, you will find that nothing is actually there and be prompted to search other signals. Either search them all or head directly to the signal farthest east on your map. You'll know it's the right one because of all of the Kett surrounding it. Fight them off and find the transponder.
At this point the mission will go on hold because the transponder is damaged and Cora needs to analyze it more. So go do some side missions and come back later.
After a few missions and returning to your quarters on the Tempest, you will find that Cora has once again emailed you. Read it and then speak with her on board. She will now tell you that she found the signal to another ark, the Leusinia and that you need to go to the Valay system to find it. Head there and scan the cluster to find it and then dock with it.
Once on board, head towards the bridge and meet with the Pathfinder. After a conversation, you will ride the tram to Hangar Control where you will meet up with Vederia. Speak with her and then go to the nearby console to override the Hangar Doors. Doing so, you will be attacked by several waves of Kett. Fight them off but stay in range of the console while SAM overrides the doors for you. After this is done, speak with Vederia again, who will tell you about something else on board draining power and the need to activate the fire suppression system. Following your conversation, head through living quarters, following your marker and fighting off some Kett. When you reach your destination, you will be in for another big fight with more Kett. Defeat them and attempt to activate the suppression system. It will fail. Scan the floor and follow the conduit to a junction box on the wall. Use that and then activate the fire suppression again. After this is done, Vederia will call you and tell you to meet her on the Observation Deck. Head there and speak with her. She will show what has been draining the power on the ship ... its a Mass Effect Field Device. You need to disable it, but to do so, you will need to disconnect 3 cables first. Be aware that after each cable that you disconnect, you will be attacked by a wave of Kett. Fight off the Kett and disconnect the 3 cables, then turn off the Mass Effect device. Turning it off will cause a breach in the hull with which the Kett will use to enter and attack you. You'll be told to head to Deck 12 to fight them off. Head there (It's right next door) and fight off several waves of Kett. The final wave you will fight the Valiant himself (herself?). Fight the Valiant just like a Cardinal: Shoot the orb, disable the shields and do damage to the Valiant.
After it's defeat, there will be several cut-scenes and you will need to make a decision involving the Pathfinder. The decision will not effect the outcome of this mission, so do as you please. After your decision, you will have a final conversation with Cora on board the Tempest. After this conversation, the trophy will unlock.