This is a posting that is unashamedly for Apollo nerds. If you are over sixty years old, you probably remember Apollo and lived the Moon landings, at least the first one, as I did. People of my generation are bathing in a stream of glittering memories as we pass the fiftieth anniversary of one epic Apollo flight after another. Happily, a few of the astronauts who walked on the Moon and a few more who orbited it, are still with us. A number of them will, with mixed feelings, see the return to the Moon with Artemis: first, a circumlunar flight and then an actual landing: flights that will happen far later than they ever imagined possible fifty years ago.
For most people though, Apollo is just ancient history; something that happened long before they were born. It is something that their parents or grandparents remember, but now is only known through fuzzy, archival TV images and photographs of a stark, grey landscape.
What many people do not realise is how much larger and more extensive the Apollo project was than just those few, crewed landings on the Moon. So, let’s get back to the original question.
It seems like an stupid question. The last Apollo was 17, so, there were 17 Apollo flights: right, Stupid?
Actually, no. Apollos 2 and 3 do not exist. There were four Apollo flights in the Skylab programme, and then the Apollo-Soyuz, but the numbered Apollos 18 to 20 were cancelled, as were two more manned Skylab flights, although Apollo-Soyuz, the very last Apollo-Saturn launch, is sometimes called Apollo 18. And Apollo 1, was actually intended to be the fourth flight of the Apollo programme, but never flew and the name was retired at the behest of the wishes of the widows of the astronauts, although the rocket that it was intended to fly on eventually launched Apollo 5. All clear now? I thought not…
The Apollo programme was much more extensive than most people realise and much more ambitious. The first launch with Apollo hardware came well before John Glenn’s first American orbital flight. While most people know that the last three Moon landings were cancelled, there were many more planned crewed flights that never made it into space as ideas and priorities changed.
In fact, nearly a dozen planned crewed flights with Saturn rockets that were cancelled in total, many of which are now almost forgotten and there were many un-crewed Apollo-Saturn test flights prior to the first official flight by Apollo 4.
In all, there were:
- 37 Apollo launches (of which only 17 were formally part of the Apollo Moon programme, although all used Apollo-Saturn technology and many of them used a generic Apollo project flight patch as theit mission flight patch).
- Of these, 37 launches in total, there were
- 16 crewed Apollo launches
- 21 un-crewed launches
In addition, there were
- 11 cancelled crewed flights[i]
- 1 crewed flight that never happened and that was designated a posteriori.
- 2 pad abort tests that I exclude because they only used the Pad Abort System with a boilerplate Command Module, so did not receive an “AS” (Apollo Saturn) designation because they were not flown with a launcher.
The Apollo Programme Fleet
The Little Joe II
Designed for launch escape tests.
These small rockets launched boilerplate Command and Service Modules to modest altitudes to test the ability of the launch escape system to abort safely in flight.
This is the first Little Joe II flight, A-001, which carried a recognisable, boilerplate Command and Service Module.
The Saturn I
The first Saturn rocket to fly, launched before even John Glenn orbited the Earth.
Intended to carry a crewed Apollo capsule into space, its limited payload led to the crewed flights being cancelled, though numerous uncrewed Saturn I rockets were flown.
This was the SA-1 launch, the first Saturn I flight, in October 1961.
The Saturn IB
NASA’s first heavy lift launcher. A two-stage rocket that launched from a platform on the launch pad. It was a huge advance on the Saturn I.
This is the Skylab 4 launch.
The Saturn V
This was the iconic Super-Heavy Lift launcher of the Moon programme.
Its payload capability to Low Earth Orbit is unlikely to be approached before the end of the decade, at least 55 years after it last flew.
This is Apollo 4, the first Saturn V launch.
Numbering and naming conventions
The naming and numbering of Apollo launches, particularly the early ones, is a bit of a mess. There is also some confusion with the final Apollo flights with some sources suggesting that there was intended to be an Apollo 21, using a possible extra Saturn V that was never ordered (this, though, appears to be an apocryphal story) while, although Apollo-Soyuz was not numbered, many space enthusiasts call it, totally unofficially, Apollo 18.
Different parts of the Apollo-Saturn programme ran simultaneously, meaning that the list below is nowhere near chronological order. Instead it is listed by its sub-programme, which was (usually) designated by the launcher assigned to the mission:
- Sub-orbital launch escape tests were designated “A-00*” if they included a Command and Service Module (CSM). None of these passed the von Karman Line at 80km altitude, with the highest apogee reaching just under 24km altitude.
- Un-crewed Saturn 1 launches were designated as “AS-1**”.
- Planned, crewed Saturn 1 flights were designated “SA-*”, although all were cancelled in 1963.
- Saturn 1B launches were designed “AS-2**”
- Saturn V launches were designated as “AS-5**”.
Part of the confusion is due to the fact that the early Apollo Moon programme flights were only known by the “AS” designation assigned to the launcher, while the final flights with the Saturn rockets and Apollo capsules were a limited sub-set of missions that were proposed originally as the Apollo-Applications program, for extended missions with Apollo hardware that included a proposal for a setting up moonbase and many other ambitious missions. These last, very much reduced in scale, became Skylab and Apollo-Soyuz, but were not considered to be part of the Apollo programme itself.
Just to add to the confusion, there are other anomalies such as the fact that AS-203 launched before AS-202.
What happened to Apollos 1, 2 and 3?
The crew of AS-204 called their flight “Apollo 1”, but it was only officially designated as such as a posthumous honour to the crew by NASA, whereby the name was retired, hence no flight named Apollo 1 ever flew. However, the AS-204 launcher itself was later flown as Apollo 5.
It has been argued that next planned crewed flight, AS-205, would have been designated Apollo 2 and that the mission that combined AS-207 and AS-208 (and, on the cancellation of AS-205, would have combined that launch too, thus sometimes appearing as AS-258 to reflect this combined status) would have been designated Apollo 3 but, again, this seems to have been contemplated only a posteriori, after the Apollo 1 fire, aimed to draw a line under the problems that the programme had at the time. This line-drawing was consecrated by the decision to retire the names Apollo 2 and Apollo 3 and start un-crewed tests afresh with Apollo 4.
NASA, apparently, planned to continue to use only the “AS” designation for all these early test flights, un-crewed and crewed, even if the assigned crews referred to them as Apollo 1, 2 and 3. Just to confuse things further, AS-205 had already been cancelled as unnecessary duplication of AS-204 even before the Launchpad fire so, in a further twist, the flight that some sources refer to as Apollo 2 would never have flown anyway.
The crew of the cancelled AS-205 flew, eventually, on Apollo 7, with a similar mission to that planned originally for AS-205, even using the same launcher, AS-205, but with a very much upgraded Command Module. So, in reality, Apollo 2 is synonymous with Apollo 7 and thus it makes no sense to talk of an Apollo 2 mission that was never going to fly anyway.
The crew of the cancelled AS-207/208 mission flew on Apollo 9. In this case, rather than being a double launch – astronauts on AS-207, Lunar Module on AS-208, both with the Saturn IB – with Earth-orbit rendezvous, Apollo 9 flew as a single launch aboard Saturn V, AS-504. So, again, Apollo 3 is synonymous with Apollo 9, thus it makes no sense to talk of this cancelled flight as Apollo 3.
Other naming anomalies
AS-209 and AS-513 are also repeated designations because the launcher was re-assigned from a previous mission that did not fly. The launch of the Skylab Space Station used the Saturn V originally assigned to Apollo 18 (AS-513), while the Saturn IB designated AS-209 was assigned to two cancelled missions and then assigned as back-up launcher for two more, before finally retiring without flying, despite having once even made it as far as the launch pad. The launcher for AS-204 – Apollo 1 – later flew, un-crewed, as Apollo 5. There was no planned flight designated AS-206 prior to the Moon landings (this number was jumped in the planning), but the first manned Skylab flight flew, five years later, on AS-206, at which point the numbering sequence continued with AS-207, AS-208…
The full list of Apollo flights, including cancelled flights
So, here is the full list of what I consider to be Apollo flights, official… and otherwise, including cancelled flights. This has been compiled from multiple sources, so it is quite possible that I have missed something or, worse, got confused somewhere:
|AS Designation||Apollo Designation||Launcher||Launch date||Crew||Objective|
|QTV[ii]||–||Little Joe II||28/08/1963||Un-crewed||Qualification flight for sub-orbital launch escape system tests.
|A-001||–||Little Joe II||13/05/1964||Un-crewed||Sub-orbital launch escape system test.
|A-002||–||Little Joe II||08/12/1964||Un-crewed||Sub-orbital launch escape system test.
|A-003||–||Little Joe II||19/05/1965||Un-crewed||Sub-orbital launch escape system test.
|A-004||–||Little Joe II||20/01/1966||Un-crewed||Sub-orbital launch escape system test.
|SA-1||–||Saturn 1||27/10/1961||Un-crewed||Sub-orbital test with dummy Saturn IV upper stage.
First Apollo Saturn flight
|SA-2||Saturn 1||25/04/1962||Un-crewed||Sub-orbital test with dummy Saturn IV upper stage|
|SA-3||–||Saturn 1||16/11/1962||Un-crewed||Sub-orbital test with dummy Saturn IV upper stage|
|SA-4||–||Saturn 1||28/03/1963||Un-crewed||Sub-orbital test with dummy Saturn IV upper stage|
|SA-5||–||Saturn 1||29/01/1964||Un-crewed||Test to orbit with live Saturn IV upper stage|
|AS-101||–||Saturn 1||28/05/1964||Un-crewed||Launched boilerplate Command and Service Module into orbit|
|AS-102||–||Saturn 1||18/09/1964||Un-crewed||Launched boilerplate Command and Service Module into orbit|
|AS-103||–||Saturn 1||16/02/1965||Un-crewed||Launched boilerplate Command and Service Module into orbit|
|AS-104||–||Saturn 1||25/05/1965||Un-crewed||Launched boilerplate Command and Service Module into orbit|
|AS-105||–||Saturn 1||30/07/1965||Un-crewed||Launched boilerplate Command and Service Module into orbit|
|SA-11||–||Saturn 1||Cancelled||Crew not assigned||Low Earth orbit test of CSM in 1965|
|SA-12||–||Saturn 1||Cancelled||Crew not assigned||Low Earth orbit test of CSM in 1965|
|SA-13||–||Saturn 1||Cancelled||Crew not assigned||Low Earth orbit test of CSM in 1965|
|SA-14||–||Saturn 1||Cancelled||Crew not assigned||Low Earth orbit test of CSM in 1966|
|AS-201||–||Saturn 1B||26/02/1966||Un-crewed||Apollo spacecraft test|
|AS-202||–||Saturn IB||25/08/1966||Un-crewed||Apollo spacecraft test. Launch delayed due to spacecraft problems|
|AS-203||–||Modified Saturn 1B||05/07/1966||Un-crewed||Test of Saturn IVb|
|AS-204||Apollo 1||Saturn 1B||Planned for 21/02/1967||Gus Grissom
|Crew killed in pre-launch fire during a test.
Designated “Apollo 1” a posteriori.
|AS-205||–||Saturn 1B||Cancelled||Wally Schirra
|Intended to be a second orbital test flight.
Potentially Apollo 2, but flew as Apollo 7
|AS-207/208 (also called AS-258)||–||Saturn 1B/Modified Saturn IB||Cancelled||James McDivitt
|Rendezvous of crewed AS-207 with a Lunar Module launched on AS-208.
Later combined with cancelled AS-205.
Potentially Apollo 3, but flew as Apollo 9
|–||Apollo 2||–||–||–||Name never used and retired|
|–||Apollo 3||–||–||–||Name never used and retired|
|AS-501||Apollo 4||Saturn V||09/11/1967||Un-crewed||First Saturn V test|
|AS-204||Apollo 5||Saturn 1B||22/01/1968||Un-crewed||Flew the unused rocket from Apollo 1|
|AS-502||Apollo 6||Saturn V||04/04/1967||Un-crewed||Second Saturn V test.
Multiple engine failures due to damage from pogo
|AS-205||Apollo 7||Saturn 1B||11/10/1968||Wally Schirra
|First crewed Apollo flight.
Low Earth orbit
|AS-503||Apollo 8[v]||Saturn V||21/12/1968||Frank Borman
|First crewed Saturn V flight.
Orbited the Moon
|AS-504||Apollo 9||Saturn V||03/03/1969||James McDivitt
|Low Earth orbit test of Lunar Module|
|AS-505||Apollo 10||Saturn V||18/05/1969||Thomas Stafford
|Lunar landing rehearsal|
|AS-506||Apollo 11||Saturn V||16/07/1969||Neil Armstrong
|First Moon landing|
|AS-507||Apollo 12||Saturn V||14/11/1969||C. “Pete” Conrad
|Second Moon landing|
|AS-508||Apollo 13[vii]||Saturn V||11/04/1970||James Lovell
|Failed Moon landing.
Crew returned safely
|AS-509||Apollo 14||Saturn V||31/01/1971||Alan Shepard
|Third Moon landing|
|AS-510||Apollo 15||Saturn V||26/07/1971||David Scott
|Fourth Moon landing.
First with Lunar Rover
|AS-511||Apollo 16||Saturn V||16/04/1972||John Young
T. Kenneth Mattingly
|Fifth Moon landing|
|AS-512||Apollo 17||Saturn V||07/12/1972||Eugene Cernan
|Sixth and final crewed Moon landing to date|
|SA-513||Apollo 18||Saturn V||Cancelled||Richard F. Gordon Jr.
Vance D. Brand
|SA-514||Apollo 19||Saturn V||Cancelled||Fred Haise
William R. Pogue
Gerald P. Carr
|SA-515||Apollo 20[x]||Saturn V||Cancelled||Never formally assigned but, probably:
Paul J. Weitz
Jack R. Lousma
|AS-513||Skylab 1||Modified Saturn V||14/05/1973||Un-crewed||Launch of the Skylab space station.
Used the Saturn V intended for Apollo 18
|SA-206||Skylab 2||Saturn IB||25/05/1973||Pete Conrad
|First crewed mission.
Repaired launch damage to Skylab
|SA-207||Skylab 3||Saturn IB||28/07/1973||Alan Bean
|Second crewed mission|
|SA-208||Skylab 4||Saturn IB||08/02/1974||Gerald Carr
|Third crewed mission.
Longest American flight pre-ISS
|SA-209??||Skylab 5||Saturn IB||Cancelled||Vance Brand
William B. Lenoir
|Shorter mission to boost Skylab to a higher orbit|
|SA-209[xii]||Skylab Rescue||Saturn IB||Not used[xiii]||Vance Brand
|Potential rescue mission for Skylab crews.|
|SA-210||Apollo-Soyuz Test Mission||Saturn IB||15/07/1975||Thomas P. Stafford
Vance D. Brand[xiv]
Donald K. “Deke” Slayton
|Sometimes termed, unofficially, Apollo 18.
Final launch of Apollo hardware
Saturn rocket nomenclature
This table also helps to clarify some of the Saturn nomenclature that has puzzled fans of the Apollo programme for many years:
- Why was the 1st Stage of the Saturn V called the Saturn Ic, yet the 2nd Stage is just the Saturn II?
- Why was the 3rd Stage, the Saturn IVb?
This, to many space enthusiasts is a curiosity. The three stages of the Saturn V rocket were, respectively: the Saturn Ic, the Saturn II and the Saturn IVb. Where is the Saturn III?
- The very earliest Saturn rockets to launch – starting in October 1961 – were the Saturn 1. The Saturn 1 was a medium-lift capability rocket. Although man-rated and designed to fly crew missions, it was underpowered to lift a crewed Command and Service Module into orbit.
- The Saturn 1 was replaced with the heavy-lift Saturn IB, a second-generation Saturn 1.
- So, the 1st Stage of the Saturn V became the third-generation Saturn 1, although with a lower case “c”, i.e. the Saturn Ic, to designate that it was a stage, not a complete launcher.
In contrast, the only use of the Saturn II was as the 2nd Stage for the Saturn V. Hence it needed no suffix.
- The second stage of the Saturn 1 was called the Saturn IV. It used a cluster of six engines.
- It was replaced by the Saturn IVb, used on the Saturn IB and Saturn V rockets so, again a lower case suffix is used as it was stage name, not a complete launcher name.
- As a measure of the advance that the Saturn IVb represented compared to the Saturn IV, the Saturn IVb’s single J-2 engine developed more than twice the thrust of the six, RL-10 engines combined in the Saturn IV.
At the start of the Moon programme, there were five potential Saturn rocket configurations: C1, C2, C3, C4 & C5. The C1 and the C5 evolved into the Saturn I and Saturn V respectively, while 2 was used for the 2nd Stage of the Saturn V and “4“ for the 2nd Stage of the Saturn I/IB that was used as the 3rd Stage of the Saturn V. By a series of historical accidents though, the number “3” was never used again, hence there never was a Saturn III.
[i] Four of these flights were initially planned to be launched, crewed, with the Saturn I, concurrent with the final Gemini flights. However, the Saturn 1’s payload capability to Earth orbit was found to be too small to make the flights worthwhile, so they were replaced with Saturn 1B launches using the more powerful successor of the Saturn 1, only one of which eventually flew in the aftermath of the Apollo Launchpad fire.
[ii] I include this flight, the only one in the list with no Apollo-Saturn or Apollo designation, because it used the same technology as the four test flights with the Little Joe II, flying a recognisable, dummy CSM.
[iii] Originally Don Eisele was named, but dislocated his shoulder twice in weightless training. The injury required surgery, leading to him being replaced by Chaffee.
[iv] Always referred to during flights as “Rusty”.
[v] Originally, Apollo 8 was intended to be the Low-Earth Orbit test of the Lunar Module (LM). Due to delays in the LM and the possibility that the Soviet Union would made a crewed flight round the Moon ahead of Apollo 9, Apollos 8 and 9 were swapped. However, the launcher designations swapped with them so, even though Apollo 8 used what was, in theory, AS-504, it flew as AS-503.
[vi] Jim Lovell replaced Michael Collins, who needed surgery for a compressed disk.
[vii] Originally, the Apollo 13 crew was assigned to Apollo 14 and vice versa but, due to the inexperience of Alan Shepherd’s crew, it was felt that they needed extra training time and the two crews and flights were swapped. Lovell’s crew, who would have landed close to Taurus crater, were re-assigned to land in the Fra Mauro Hills, the target for Alan Shepherd’s crew. After the Apollo 13 accident, Taurus crater was dropped as landing site for Apollo 14 and replaced by Fra Mauro, which was regarded as a much higher priority target. As with the Apollo 8/9 swap, the launcher sequence numbering was maintained rather than being swapped too.
[viii] Jack Swigert replaced Ken Mattingly two days before launch, as Mattingly had been exposed to German Measles and could, potentially have fallen ill on the way to the Moon. In the end, Mattingly did not fall sick and flew on Apollo 16 instead, replacing Swigert.
[ix] Harrison Schmidt replaced Joe Engle when Apollo 18 was cancelled.
[x] Had Apollo 20 flown it would, most likely, have landed in Tycho crater – probably one of the roughest areas of the Moon and an exceptionally difficult landing site – although Harrison Schmitt campaigned for a lunar farside landing, arguing that it should be combined with the placement of a chain of communications satellites in lunar orbit to allow continuous communication with astronauts on the lunar farside.
[xi] By the standard crew rotation, Pete Conrad (back-up commander on Apollo 17) should have commanded this flight, but Deke Slayton’s rules excluded an astronaut from commanding two Moon flights, placing Stuart Roosa, as Commander on the “six flights after acting as Command Module Pilot” rule.
Initially, when there were many potential lunar landing spots, Deke Slayton had intended to use a mixture of rookie astronauts and former Lunar Module Pilots in the later landings, giving the former experience and the latter the chance to command a flight. By the time of Apollo 11, the idea of allowing Lunar Module Pilots to walk on the Moon twice appears to have been dropped completely and only Command Module Pilots had a chance of making two lunar flights.
[xii] SA-209 was kept in reserve for Skylab 4 and for Apollo-Soyuz too, although it never made it into space in the end. It was placed on display at the Kennedy Space Center.
[xiii] This mission was rolled out to Pad 39B for a potential rescue when the Command and Service Module (CSM) of Skylab 3 developed some issues that could, potentially have left it unusable for the return to Earth. Eventually, the controllers at Mission Control were able to fix the problems and the AS-209 launcher was stood down and rolled back.
[xiv] Originally, Jack Swigert was intended to be Command Module Pilot, but was replaced by Vance Brand after falling into disgrace after the Apollo 15 First Day Cover scandal.