After the Gemini 3 craft was dubbed "Molly Brown" by Grissom, NASA forbade naming spacecraft. The fact that during the Apollo9 mission, the CSM and LM would separate and need different call signs caused the Apollo9 astronauts to push for a change. In simulations, they began to refer to the CSM as "Gumdrop", a name inspired by the CM's appearance while in the blue protective wrapping in which it was transported from the manufacturer, and the LM as "Spider", inspired by the LM's appearance with landing legs deployed. Personnel in NASA public relations thought the names were too informal, but the call signs ultimately gained official sanction. NASA required more formal call signs for future missions, starting with Apollo 11.