Francis Aaron was a prison guard on Fiorina 161. He was an assistant to Superintendent Andrews. Many of the prisoners refer to him as "85"; this is because of when he first came to this planet they found his file with his IQ being 85. Aaron usually responds to this by saying "Don't call me that," however they generally ignore his requests. He, like Andrews is not a religious type on 161 like many of the prisoners.
Encounter with Ripley
In 2179, Ellen Ripley crash landed on Fiorina 161 after the EEV ejected her along with Corporal Hicks, Newt and Bishop from the Sulaco due to the presence of the facehugger. A facehugger eventually emerged from the wreakage of the EEV and impregnated the prison dog, Spike. A Xenomorph eventually ruptured from Spike and matures to its adult form. It begins a killing spree in the prison, causing mass hysteria among the prisoners. Superintendent Andrews tried to take control of the situation, but was killed by the Alien during his "rumor control".
Aaron tried taking charge after Andrews' death, but the prisoners didn't allow it. They elected to have Dillon be the leader, who chose not to lead and appointed Ripley. In many parts of the movie he gets into heated arguments with Ripley and Morse. Aaron, having faith in Weyland-Yutani, states his belief that they'll take the survivors away to safety; Ripley rebuts, saying that they'd probably kill them just for having seen the creature. He argues with Morse and other prisoners simply because of his IQ and saying "At least I'm smart enough not to have a life sentence on this rock!"
Discovering the Truth
Ripley demands that he sends the rescue ship away, but he refuses, wanting to go home. In time he helps Ripley scan herself to find that she has a Queen inside of her, inadvertently informing Weyland-Yutani that she has one inside of her, causing them to move faster to claim her. Back at the monitors, Weyland-Yutani leaves a message that the ship will be there to pick Ripley up in a matter of hours since everything on the planet goes to them they found out about the Alien and the CAT Scan. He then understands that they do not care but just want Ripley and the Alien. While the other prisoners try to kill the Alien, he stays pent up in his office. It's assumed that in there he loses all faith in Weyland-Yutani.
Confrontation & Death
When the "rescue team" arrives and tried to convince Ripley to come with them, she refuses, and goes with Morse on the platform. Morse was then shot in the leg by one of the soldiers. As Michael Bishop was trying to convince Ripley and the others that it was a mistake, Aaron took a wrench and slammed it on the side of Bishop's head, nearly severing his ear. Aaron was then shoved away by Weyland-Yutani trooper, and then shot by another causing him to fall off the catwalk and down onto the deck and left to die. He is last seen gasping for air on the floor.