"Apollo 1" on their mission insignia patch. Problems with the simulator proved extremely annoying to Grissom, who told a reporter the problems with Apollo 1 came "in bushelfuls" and that he was skeptical of its chances to complete its fourteen-day mission. Grissom earned the nickname "Gruff Gus" by being outspoken about the technical deficiencies of the spacecraft. The engineers who programmed the Apollo training simulator had a difficult time keeping the simulator in sync with the continuous changes being made to the spacecraft. According to backup astronaut Walter Cunningham, "We knew that the spacecraft was, you know, in poor shape relative to what it ought to be. We felt like we could fly it, but let's face it, it just wasn't as good as it should have been for the job of flying the first crewed Apollo mission." NASA pressed on. In mid-January 1967, "preparations were being made for the final pre-flight tests of Spacecraft 012." On January 22, 1967, before returning to Cape Kennedy to conduct the January 27 plugs-out test that ended his life, Grissom's wife, Betty, later recalled that he took a lemon from a tree in his back yard and explained that he intended to hang it on that spacecraft, although he actually hung the lemon on the simulator (a duplicate of the Apollo spacecraft). Death and legacy Before Apollo 1's planned launch on February 21, 1967, the Command Module interior caught fire and burned on January 27, 1967, during a pre-launch test on Launch Pad 34 at Cape Kennedy. Astronauts Grissom, White, and Chaffee, who were working inside the closed Command Module, were asphyxiated. Just prior to their death, Grissom had remarked, "How are we going to get to the Moon if we can't talk between two or three buildings?" before shouting "Fire!" Those would prove to be his last words. The fire's ignition source was found to be damaged wiring. Their deaths were attributed to a wide range of lethal hazards in the early CSM design and conditions of the test, including a pressurized 100 percent oxygen prelaunch atmosphere, wiring and plumbing flaws, flammable materials used in the cockpit and in the astronauts' flight suits, and an inward-opening hatch that could not be opened quickly in an emergency and not at all with full internal pressure. Grissom's funeral services and burial at Arlington National Cemetery were held on January 31, 1967. Dignitaries in attendance