See AC Sparkplug
AC Sparkplug was the principal contractor for the construction of Apollo guidance systems.
Originally designated AS-204, Apollo 1 was scheduled to be to launch on February 21, 1967 as the first manned Apollo mission. During a test on January 27, 1967, a fire in the crew compartment killed the three Apollo 1 austronauts, Gus Grissom, Ed White, and Roger Chaffee. This fire resulted in reappraisal of just about every goal, procedure, and schedule of the Apollo program.
See Apollo 1
Originally scheduled as the first unmanned flight of the LM, it was cancelled after the Apollo 1 fire. The AS-206 launch vehicle, a Saturn 1B, was used to launch Skylab 2 on May 25, 1973.
AS-207/208 (also known as AS-278) was to have been the first test of the LM in Earth orbit. It was also to have be a dual mission with the command and lunar modules launched on separate Saturn 1Bs. The mission was cancelled after the Apollo 1 fire and the Saturn 1Bs were used to launch Skylab 3 (AS-207) on July 28, 1973 and Skylab 4 (AS-208) on November 16, 1978. The LM was first tested by Apollo 5 in January 1968.
Before the Apollo 1 fire, the mission referred to as AS-503 was originally scheduled for October 1967. AS-503 eventually launched as Apollo 8, December 23 1968.
Before the Apollo 1 fire, the mission referred to as AS-504 was originally scheduled for December 1967. AS-504 eventually launched as Apollo 9, March 3 1969.
Apollo Spacecraft Program Office.