United States Senator representing California. Armstrong possessed strong ties to the International Oversight Advisory, helping to fund $1.6 billion from the U.S. government to the Icarus Project which was developed to explore the purpose behind the Stargate's ninth chevron. It was Armstrong's daughter (and attaché) Chloe, who convinced him the project merited funding, despite his feelings that there were "terrestrial matters" which were more important.
The Senator and his daughter traveled to the Icarus planet to witness the fruits of the expenditure, but the test was a failure. Only when Icarus Base fell under attack did the proper solution present itself, and the entire facility -- including Armstrong and his daughter -- was forced to evacuate to the ninth chevron address to escape the attack.
Air conditions aboard the Destiny proved deadly for Armstrong. Blood thinner pills for his heart condition proved counterproductive with the thin atmosphere and his bruised ribs. Chloe explained to her father that the one section of the ship that was venting atmosphere was a shuttle, the door of which would not seal without someone inside. With an hour of air remaining for the crew, Armstrong sacrificed his life by confining himself into the shuttle and plugging the hole, re-pressurizing the ship.
Following his death, Chloe spoke fondly of her father, saying he was a man who would always take the time for her in spite of his busy schedule. He would be remembered as a hero to the Icarus personnel.
Air, Part 1 - Senator Armstrong travels with his daughter to the Icarus planet to witness the Stargate connect to the ninth chevron, but finds he must evacuate to the other side to avoid the destruction of a surprise attack.
Air, Part 2 - His hours numbered, Senator Armstrong sacrifices himself to preserve those of his daughter and the rest of the Icarus team.
Pain - Infected with an alien tick, Chloe hallucinates her father -- and, though she knows he isn't really there, has a heart-to-heart conversation that gives her the chance to truly say goodbye.