Ensign Beltre was a Starfleet security officer who served aboard the USS Enterprise in the 2260s. In late 2265, Beltre attended Lieutenant Lee Kelso's memorial service in the ship's chapel.
At the service she spoke of how Kelso had made her feel welcome when she signed aboard the Enterprise, and how one day, when she was sat in the mess hall, Kelso ordered two cups of coffee, placed one on her table, and then sat with his at the other. Realizing that this was an invitation to join him, she accepted, and the two would often share coffee. When she later asked him about what he did, Kelso said that his time in the orphanage in Los Angeles made him realize that he would never let anyone be alone again. (TOS - My Brother's Keeper novel: Constitution)