A refugee suggested that a Prothean sphere could be located somewhere on Gei Hinnom in the Hades Nexus. Locate the sphere and inform the man at the Citadel refugee camp.
Alternative journal entry:
A Prothean sphere was recovered from the Hades Nexus. Find someone on the Citadel who can use it.
Acquisition[]
Listen to the refugee in Bay E28 on Docks: Holding Area, or point #4 on the area map. He's begging the turian guard for some food in exchange for the location of Prothean ruins.
Alternatively, a Search and Rescue operation in the Hades Nexus will yield the sphere and this mission's journal entry. In this case it is labeled Citadel: Prothean Sphere.
Walkthrough[]
The Hades Nexus only becomes available after Priority: Rannoch. That is a gap of at least 4 Priority missions from earliest mission acquisition to mission completion: pretty sure the refugee's family will be starving for quite a while even if you decide to help ASAP. Scan Gei Hinnom in Sheol in the aforementioned cluster. Give the artifact to the refugee when you return to the Citadel: you'll instruct him to sell the artifact to the Alliance on Shepard's authority.
After handing over the artifact, you will gain 5 Reputation, 15,000 credits and an update to the Alliance Engineering Corps War Asset. If you talk to the refugee again, it turns out he used the money to buy food not only for himself and his family, but also for some others who are also trapped on the station.