optical tracker - Space Rocket History Podcast

Toward the end of January 1967, it was revealed that Lunar Module 1 would not reach the Cape in February, as expected. This meant, the moon landing might be delayed because the lander was not ready. But the mission planners could not wait for the Apollo engineers to iron out all the problems. They had to plan for a landing in 1969 and hope that the hardware would catch up with them.