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 PART ONE - BLACK OPS ON THE MOON

 Chapter 1 - Where are the Apollo 10 & 11 Lunar Modules?

Section II

The types of orbits, and some anomalies.

The best way to describe the orbits involved in an Apollo mission is to describe all of the elements of such a mission, so here goes.

The very first thing to remember is that when you are in space around the Earth and Moon the spacecraft, or any object, will keep moving without any help from you, and the direction and speed of motion (velocity), of any object will remain constant except for changes caused by the natural forces below, or by some other type of force, such as the push from a rocket engine. Some of the natural forces effecting the path of any object in space around the Earth and Moon are listed below.

When one of the Apollo spacecraft blasted off it went into a parking orbit around the Earth. This was generally a circular orbit. They stayed here until everything could be checked out and the time was right for the next move.

(Courtesy DOD/NASA)

When everything was ready, they fired up the S-IVB engines and went into a translunar orbit. Translunar was just a fancy way of saying that they were on their way to the Moon! A translunar orbit is also a cislunar orbit, but a transearth orbit is also a cislunar orbit. I guess they needed to use this word so everyone would know they were headed to the Moon, and not somewhere else! Cislunar means between the Earth and Moon. Now a lot of things happened in the translunar phase of the mission.

(Courtesy DOD/NASA)

After they were on their way to the Moon the next thing that happened was to separate the CSM from the rocket and then to turn around and dock with the Lunar Module. The combined CSM and LM was then separated from the S-IVB.

(Courtesy DOD/NASA)

What happened next depended on which mission we‘re talking about, on a few of the Apollo missions the S-IVB was sent crashing onto the Moon. On all of the other missions it was sent into a Solar orbit, (except for one time when it went into a cislunar orbit), by pointing it to pass the back side of the Moon. The Apollo 8 Orbital Plan shows this clearly with the dotted line.

(Courtesy DOD/NASA)

I can’t convey enough that every object including debris that was sent on its way towards the Moon continued in that path except as acted upon by one or more of the natural forces listed above, or by a rocket engine. The fate of each object is for another part of this chapter.

After the CSM/LM was heading for the Moon in the translunar orbit it continued in that path except for minor course corrections, gradually slowing down because it was being pulled back to the Earth by the Earth‘s gravity.

When the craft reached the neutral point, where the gravity field of the Earth and the Moon was equal it started to accelerate towards to Moon. Every other object heading out to the Moon also reached a neutral point somewhere in its travels.

The CSM/LM now was heading to a point on the leading edge of the Moon. If no further action was taken then the craft would go on by the Moon. But the purpose was to go into an orbit around the Moon, right? So what they had to do was to turn the spacecraft around so the rocket engine was pointing in the direction of travel and fire it for a few minutes, slowing down the spacecraft.

(Declassified Apollo 11 document, Courtesy DOD/NASA)

This put the spacecraft into an elliptical orbit around the Moon. On another pass on the back side further maneuvers would be taken to put the craft into a more nearly circular orbit.

The CSM/LM is now in selenocentric or lunar orbit. The CSM will stay in this orbit until they leave to head back to the Earth. But the LM will separate from the CSM and will land on the Moon, except for Apollo 10 and 13. The top half or ascent stage of the LM will take off from the Moon’s surface and go into a selenocentric or lunar orbit. It will then join up with the CSM.

(Declassified Apollo 11 document, Courtesy DOD/NASA)

When they are ready to return to Earth they will fire up those old rocket engines and go into a transearth orbit heading home.

(Declassified Apollo 11 document, Courtesy DOD/NASA)

They only thing needed now is maybe a few small course corrections to put them in the correct heading to be at the right place when they reach the Earth. One of the last things they will do is separate or jettison the CSM and just the command module itself will make it back to the Earth with people on board. The CSM will burn up in the Earth’s atmosphere. Here is a complete mission in one drawing, Apollo 10.

(Courtesy DOD/NASA)

So in a nut shell that is a description of an Apollo mission to the Moon. But it would be a little interesting to talk about some of the more finer details of orbits concerning the Apollo missions. Mascons, remember them? Short for mass concentrations. When Russia and the US started sending spacecraft to the Moon long before the Apollo missions they noticed that their orbit calculations were not keeping the spacecrafts in the right orbits sometimes.

One thing I forgot to mention is that if you have a homogeneous body in space with no atmosphere, such as the Moon, once another body is put into orbit around that body it will stay there forever. As a matter of fact, the space junkyard which is near geosynchronous earth orbit, (this is where they move all of the communication satellites that have died), will hold the craft in these orbits millions of years, or forever there. That is because they are to far above the Earth’s atmosphere for it to have any effect on those orbits.

(Courtesy DOD/NASA)

But for some as yet unexplained reason there are huge masses under the seas or maria on the Moon. What is interesting is that none of the scientific theories that try to explain the creation of the Moon and/or the Earth/Moon system can account for these mascons. I guess that is why they are called theories. Here is a picture from DOD/NASA showing these areas, (in red).

(Courtesy DOD/NASA)

The gravity in these areas is so much stronger that a person would actually weigh about 4 ounces more if they walked over one of these areas! But the most amazing thing is that they effect the orbit path of everything going around the Moon in lunar orbit. As a matter of fact DOD/NASA claims that is the reason for so many of their spacecraft that have crashed on the Moon. But other craft have stayed in lunar orbit for years, go figure. More on this later in another part of this chapter.

So what everyone is being told is that you must take along a lot of fuel for orbit maintenance or just put your spacecraft in one of the stable lunar orbits, if you plan on staying around the Moon for very long.

Computer simulations now show that there are very few stable orbit around the Moon. This is not the place to go into any detailed calculations of spacecraft orbits. For those interested enough there are levels of expertise from simple circular orbits all the way up to genius level, remember Einstein is most well known for his theories of relativity, and the general theory is about gravity, space, and time.

Another strange thing about lunar orbits is that if an object is about 700km or more miles above the surface then the gravity field of the Earth will have such an effect that it is very possible the Earth may pull it away from the Moon and capture it! There is a constant tug on all things in space from every large body in our Solar System. Sometimes nobody knows which one will win out.

A word about spacecraft launched into lunar orbit. Most spacecraft sent to the Moon was put there by rockets with multiple stages, usually two or more. The first one or two stages were jettisoned in Earth orbit. Very early on in the space program it was realized that it was much easier to hit the Moon if a spacecraft was put into a parking orbit around the Earth then the spacecraft was sent on its way with a much smaller rocket to place it onto a path to hit the Moon. All of the Apollo spacecraft used this procedure and most of the successful USSR and US spacecraft sent to the Moon did the same. The procedure of using a rocket circling the Earth to put a spacecraft into an orbit to hit the Moon was called TLI, (trans lunar injection).

But what happens if an object does not go into an orbit around the Moon? The Apollo 13 flight gives a good example of that.

(Apollo 13 drawing showing the path of the CSM/LM
after the original hybrid transfer maneuver, showing both orbits.)
(Courtesy US Congress & DOD/NASA)

(Apollo 13 drawing showing the two paths of the CSM/LM, after reverting
back to the free return, and the original after the hybrid transfer maneuver.)
(Courtesy US Congress & DOD/NASA)

(A very good drawing showing a typical Apollo mission
and paths of the S-IVB and CSM/LM)
(Courtesy DOD/NASA)

(Words in red by author)
(This diagram only shows 3 orbits, but since this is a free return
trajectory the object will continue to orbit indefinitely.)
(Courtesy DOD/NASA)

Some more thoughts about Earth-Moon orbits, many different names are used to describe various orbits. Different countries, people, organizations, documents, etc. sometimes use different names to describe the same type of orbit, for instance sometimes “cislunar orbit” and “highly eccentric orbit” can mean exactly the same thing, other times it means different types of orbits. The technical phrase cislunar means between the Earth and Moon. Therefore an orbit that goes around the Earth and Moon but never goes between them technically cannot be a cislunar orbit. So as not to get to technical in this chapter I am going to use the following types of orbits in the timeline table.

	Cislunar orbit --- An orbit that takes a spacecraft somewhere near the Moon and the Earth. It may or may not actually circle one or both of these bodies. This includes “highly eccentric orbits.”
	Selenocentric --- An orbit that circles around the Moon only.
	Orbit unknown --- I am including these because it is possible this craft may be in one of the two orbits above. No definite statements have been made that the craft went into an orbit around the Sun or that it crashed onto the Earth, Moon, or Sun. And the craft’s last known orbit may have been in one of the two obits above.

Moving around in orbit is another matter entirely. If you are in your spacecraft and you give yourself a push with your engine, what direction do you think you will go? Just faster in the same orbit? In a higher orbit? Or in a lower orbit? If you just imagine the Moon is surrounded by a bunch of invisible spheres each about a foot apart. There is attached to each invisible sphere a unique speed and velocity for that orbit. I am talking about a speed relative to the Moon's surface. The closer you are to the surface the faster you must go to stay in orbit. As you move outward from a rotating body, the relative speed slows down until you will reach a speed equal to the speed of rotation, and you will be in a synchronous orbit. Another thing to keep in mind is that if you give yourself a push into or away from the Moon you won't keep going in that direction, but you will just change orbits to match your new speed. Since the Moon does not have an atmosphere you must provide all of the continual forces for changing orbits and landing and taking off. Around the Earth once you are close enough to be in the atmosphere, it will slow you down enough to land, but this is not the case around the Moon.

I think we have enough basic information about orbits, there might be a few more specifics later, but only as it relates to an object or spacecraft.