This year marks the fiftieth anniversary of many important milestones. The Mets won the World Series. There was a music festival on a farm in New York.

Oh, and human beings walked on the moon.

Ask the average person about the Apollo Program, and they will know that it was Apollo 11 that landed the first people on the moon. Apollo 13 was the one that they made that movie about. More educated people might know that Apollo 8 was the one with that “Earthrise” photo, and Apollo 1 was the one with the fire that killed the astronauts.

Even more educated people will know that Apollo 7 through 10 were various manned flights, and that 12 and 14 through 17 actually took people to the moon.

But what about the other numbers? What about 2 through 6, and anything over 17?

At the start of the Apollo Program, NASA was giving every mission a code number. Early missions were unmanned tests of the Command Module and rockets; the code numbers indicated the combination of rocket, module, and test flight number. Mission AS-204 was planned as the first manned flight, so it was informally named Apollo 1. There were patches made up and everything. Later manned test flights would be designated with the names Apollo 2, 3, etc., while still keeping their official code names to preserve the sequence.

But after the fire, everything went out the window. Betty Grissom, Patricia White, and Martha Chaffee asked NASA if their husbands’ mission could be officially named Apollo 1. NASA agreed.

The investigation of the fire, coupled with a whole slew of delays, led to an overall renumbering of the missions. Two earlier unmanned test flights of the Saturn 1B booster rocket (AS-202 and AS-203) would be retroactively named Apollo 2 and 3. All future missions would have an official Apollo designation as well as the regular code.

Apollo 4, 5, and 6 were unmanned flight tests of the redesigned Command Module as well as the Lunar Module (Apollo 5).

Apollo 7 was the first manned flight test of the Command Module. By the summer of 1968, NASA decided it was time to kick things up a notch. Apollo 8 was supposed to be a manned flight test of the Lunar Module, but the LM wasn’t going to be ready in time to make the scheduled launch date. Rather than push things back, NASA said “What the heck, let’s send the crew all the way to orbit the moon. We’re going to have to do that test flight anyway….”

Apollo 9 got to test the Lunar Module in Earth orbit. Apollo 10 was a full-scale dress rehearsal for the actual landing.

There were missions planned after Apollo 17. Apollo 18 and 19 were canceled due to budget cuts (and not wiped from the books as part of some conspiracy nonsense). Apollo 20 was repurposed to launch Skylab, the first space station, in 1973. Leftover Apollo hardware was used for the Apollo-Soyuz mission in 1975, and that would be the end of the Apollo program.

After that, we pretty much decided that we didn’t need to send people to the moon anymore.

It didn’t seem interesting enough to justify the cost.

For the record, these are the people who orbited the moon:

Frank Borman
Bill Anders
Jim Lovell
Tom Stafford
Michael Collins
Richard Gordon Jr.
Jack Swigert
Fred Haise
Stuart Roosa
Alfred Wordin
Ken Mattingly
Ronald Evans

In addition to orbiting it, these people walked on the moon:

Neil Armstrong
Edwin Aldrin
Pete Conrad
Alan Bean
Alan Shepard
Edgar Mitchell
David Scott
James Irwin
John Young
Charles Duke
Gene Cernan
Harrison Schmitt