What is this spire on top?
What module hides inside the body of the Apollo – Saturn V?
Why does this model have an additional piece that looks like another nose cone?
(Hint: the one that is already mounted should also have an outline of a hatchway.)
How many stages does this whole thing really have?

This is the combination of the Apollo spacecraft riding on top of the Saturn V launch vehicle.
The Saturn V launch vehicle is still the only rocket to actually carried humans past low Earth orbit.
And, it still holds the record for biggest payload delivery to low Earth orbit. New record breaking rockets are still in testing or development.
Out of numerous design choices, this design was chosen for The Apollo Program for its efficiency on fuel, epitomizes solving the classic rocket engineering problem more so than the Space Shuttle and many of today’s launch vehicles. For example, Space X’s Starship is definitely greater, but only has one booster stage and the space vehicle.

Rocket engineering is a snowballing type of problem. You weigh the payload and calculate how much fuel you need to generate enough thrust. Add the weight of the fuel. Add Oxygen (or other oxidizer) and its weight because Earth’s atmosphere is already too thin by ten miles high. Add the weight of the rocket that will carry all this stuff. Keep adding more fuel and oxidizer as the calculated weight increases.
One more problem, the fuel and oxidizer gets used up over time, but the rocket structure is still there. Disposing the rocket structure that was carrying the now expended fuel and oxidizer would help save fuel, so rockets going into space almost always are broken into stages.

The Apollo – Saturn V is very tall (363 feet, including space capsule and spire) even in comparison to its width at the bottom (33 feet, not counting the engine fairings and fins. The top conic section is the space capsule that is called the Command Module (CM), which is only 12 feet and 10 inches wide at its base, but this is where all thee astronauts will spend most of the mission. Above it appears to be a spire. The cylinder section beneath it is the Service Module (SM). Together they form the Command Service Module (CSM). The SM has Oxygen and Hydrogen tanks for breathing oxygen, making water, creating thrust for the SM’s engine, and generating electricity via a fuel cell generator. Just like the Space Shuttle, there are no solar panels. These details will become critical for Apollo 13.

It took several missions to test things out step by step. The Apollo program started with the only astronaut deaths before the Space Shuttle. Retroactively named, Apollo 1, the Command Module caught on fire from an internal electrical short, killing all three astronauts.
Several missions were then done without astronauts, including debuting the Saturn V in Apollo 4.
Apollo 7 then reintroduced astronauts.
Apollo 11 was the first mission to land man on the moon, but was not the first to fly to the Moon.

Apollo Saturn V had way more emergency measures than the Space Shuttle. It had a launch escape system (LES) that comprises of a rocket motor with several nozzles aimed outward in all directions, a lattice tower holding the LES rocket to the CM cover, and a cover protecting the CM from the LES rockets. LES could left the capsule away from Saturn V, separate from the CM, then CM parachutes down to splashdown. The first stage had fins that were intended to stabilize the rocket enough for safe separation in emergencies.
After the Saturn V first stage separates, LES then separates. With the cover gone, the astronauts can now look out through the CM’s windows. If failure occurs after this point, then the SM engine fires to separate the CSM from Saturn V and performs re-entry.
As it was in Apollo 13, if the second stage had one engine not fire, the procedure was simply to burn the remaining second stage engines and then the third stage for longer periods of time.
The second stage almost carries them to low earth orbit. The third stage completes orbit. While orbiting, system checks are done, then the third stage fires again to go to the moon. When the third stage is done, the CSM fires its maneuvering thrusters to move away, doors to the lunar module adapter open, revealing the Lunar Excursion Module (LEM) and the nozzle of the CSM. CSM has four thrusters on its side with each having four nozzles pointing 90 degrees apart).
The CSM turns around, docks with the LEM. The CSM and LEM together forms the Apollo Spacecraft which also becomes an important detail for Apollo 13. The third stage fires small rockets to maneuver to the opposite side of the moon to avoid collision. In a later mission, it was sent to crash into the moon to get a seismic reading in order to see the moon’s internal structure.
The SM’s main engine is fired a few times for course corrections on the way to the moon (also on the way back from the moon). then fires again to fall into orbit around the moon.
Only two astronauts enter the LEM. One astronaut has the job of being stuck babysitting the CSM. The LEM detaches and steadily descends to the moon’s surface. In the corners between LEM’s legs are four storage compartments for tools, a camera, and later missions had a rover for riding that was packed tightly folded.
To liftoff, the LEM separates into two, leaving behind the legs, storage, and descent engine. The ascend engine has its own special fuel which is very toxic, but highly reliable, else astronauts might be stuck on the moon.
The LEM fires its ascend engine several times to return back up to the CSM and dock. The astronauts take with them what will go back to Earth, dump trash into the LEM, and separate from the LEM.
The CSM fires its engine to leave orbit and travel back to Earth, then fires again near Earth to go into re-entry. Also important in Apollo 13, before re-entry, CSM separates into the CM and SM, revealing the CM’s heat shield that was between them. All of the mighty Apollo – Saturn V has been discarded, except for the CM, which now it uses its heat shield to use as a speed brake in Earth’s atmosphere. Once down to 24,000 feet, parachutes deploy to slow down to a safe splash, but they are not in the center, since that was where the LEM docked, so the CM comes down sideways and flips upside down when it hits the water. CM has inflatable floats on its top to right itself up.

By Apollo 13, they stop using free return orbit for efficiency (sounds like the Space Shuttle), so half way to the moon, they fire the SM engine to change trajectory. Bad move, because a short time after that, one of the oxygen tanks in the SM blew-up and took out almost a quarter of the SM’s cover. The explosion was caused by an electrical component being designed for the wrong voltage. Since their windows were angled away from the SM, the astronauts could not see the damage, but could see gas venting. The astronauts had to shut down the CM so they had energy to perform re-entry. Then, they move to the LEM. They used the LEM’s descent engine to change back to free return orbit, so that they will sling shot around the moon and back to Earth. Once that is taken care of, now they they just have to survive a few days. The LEM was made to be used only for a day by two astronauts, they had to improvise Carbon Dioxide scrubbers from the CM to work in the LEM. This was enough to make up for not generating new oxygen. They had to reduce power in the LEM, since they did not have enough water to cool it. They used the LEM to charge the CM. The astronauts had to severely ration water for several days, and it was also cold, but they managed to survive their way back to earth. Before re-entry, they jettison the SM that was protecting the heat shield (they finally saw the damage), and used the LEM to maneuver for re-entry, before jettisoning it too.