This Display-Keyboard (DSKY) was one of two installed in the Command Module of the Apollo 7 mission, the first US 3-man space flight, which flew in Earth orbit in October, 1968. The DSKY was the method by which Apollo astronauts communicated with the computers on board the Apollo Command and Lunar Modules. Astronauts instructed the computer by keying in numerical codes in a "verb - noun" sequence; e.g. "display velocity." The Apollo Guidance Computer performed critical functions needed to carry out a successful mission, especially on later missions when the astronauts were behind the Moon and out of radio contact with Earth.