Astronomy:List of Apollo mission types

In September 1967, Owen Maynard of the Manned Spacecraft Center in Houston, Texas proposed a series of Apollo missions that would lead up to a manned lunar landing. Seven mission types were outlined, each testing a specific set of components and tasks, and each previous step would need to be completed successfully before the next mission type could be undertaken. These were:

• A – Unmanned Saturn V and Command/Service Module (CSM) development (Apollo 4, Apollo 6)
• B – Unmanned Lunar Module (LM) development (Apollo 5)
• C – Manned CSM evaluation in low Earth orbit (Apollo 7)
• D – Manned CSM and LM development in low Earth orbit (originally planned for Apollo 8; flown as Apollo 9)
• E – Manned CSM and LM operations, a simulated lunar mission in an elliptical medium Earth orbit with an apogee of 3,500 nautical miles (6,500 km); never flown

The planned sequence was changed when it became clear the first manned Lunar Module, LM-3, would not be ready in time for the December 1968 launch of Apollo 8, so this was flown as a lunar orbital mission using just the CSM (sometimes referred to as "a C Prime mission") and the E mission was canceled.

• F – Manned CSM and LM operations in lunar orbit, a "dress rehearsal" for the first landing (Apollo 10)
• G – First manned lunar landing (Apollo 11)
• H – precision landings with up to two-day stays on the Moon, with two lunar extravehicular activities or "moonwalks" (Apollo 12, Apollo 13 (planned), Apollo 14)
• I – long duration CSM lunar orbital surveys using a Scientific Instrument Module mounted in an empty Service Module bay. These were incorporated into the J missions.
• J – longer three-day stays using an Extended LM, with three LEVAs and a Lunar Roving Vehicle (Apollo 15, Apollo 16, Apollo 17). Apollo 18 to 20 would have been J missions. Apollo 15 was originally planned as an H mission but was promoted to J as the program was curtailed.