Apollo 11 mission reconstruction - a teamwork

[ElChristou]

Because Linuxm@n and Gilles are still working with some 1.4.x version of Celestia, I was wondering if some reference frame guru (Chris? Selden?) could take a few minutes to describe here the best way to do the extraction sequence of the LEM using those new declaration available since 1.5.x

First here are the two principal references for those interested in the question:

http://en.wikibooks.org/wiki/Celestia/Reference_Frames#BodyFrame_property
http://www.lepp.cornell.edu/~seb/celestia/celestia_notes.html#5.10.2

Perso I must admit I have some difficulties using those declarations, perhaps because my English is not good enough and I miss some subtleties or simply because I reach the limits of my tolerance to spacial geometry (who knows) , it's why I suppose it would be useful to show a well documented example, so I thought the occasion was good.

So, let's begin with a description of the extraction sequence of the LEM, step by step. I 'll expose my point of view without entering in the details of the ssc, please correct me if something is wrong.

Here is the 3rd stage; because the opening of the SLA seems to be complicated for a first example, let's forget it (I removed it but the CSM's position is unchanged)


**
We need 3 models:

The 3rd stage body,


the LEM,


and the CSM,


So at this point we have 3 declarations in the ssc. the 3rd stage should have as reference Earth. The LEM should have the 3rd stage as reference, the CSM should have or the 3rd stage or the LEM as reference (what best?)

***
Here we go for the sequence:

Step 1: Translation of the CSM:


(at this point the SLA should open and being ejected)

***
Step 2: Rotation of the CSM (180?°):


***
Step 3: Translation of the CSM for docking with LEM:


***
Step 4: Translation of the CSM/LEM:


***
Step 5: Rotation of the CSM/LEM (180?°):


***
Step 6: Translation of the CSM/LEM, direction Moon:


***

My personal question to gurus are:

What are the best references for those steps?
The rotations and translations should be declared in .q and .xyz files?
In Step 6, the Moon should be taken as reference, how to change from a reference to another smoothly?

[rthorvald]

For the ground, so i don??t forget when we get around to that part, a Quicktime 3D panorama of the landing site:
http://moonpans.com/vr/apollo11_lm.htm

... Extremely boring landscape on the 11 mission, but that??s the way it is...

- rthorvald

[selden]

To a certain extent, I think that the selection of coordinate systems depends on what you want to happen to the spacecraft models later and how you want them to be referenced in Celestia.

For example, the similar projects I've been working on, many of which are incomplete, define several separate objects which include Beginning and Ending statements. This lets me break the problem down into several separate pieces, each of which is relatively easy to construct.

In other words, while what would be visible would seem to be a single spacecraft travelling and changing direction actually would be several separate Celestia objects with different names, each doing something relatively simple at an appropriate time.

Of course, making several separate objects appear to be a single continuous body can be a little tricky. Also, this makes it almost impossible to GoTo the same spacecraft object name at different stages of the mission.

I think what I'd do would be to define a dummy object (class invisible, or a ReferencePoint, or a transparent Mesh) following an appropriate trajectory, define an OrbitFrame and a BodyFrame referenced to that dummy object, and then define the motions of the various spacecraft objects relative to those Frames.

In principle, one could define a single object following a continuous xyz trajectory with a continuous set of rotation quaternions to describe its orientations throughout its lifetime. For me, however, creating appropriate xyz trajectory and quaternion files would be quite difficult.

[rthorvald]

Of course, making several separate objects appear to be a single continuous body can be a little tricky. Also, this makes it almost impossible to GoTo the same spacecraft object name at different stages of the mission

This is a very good approach. What you do is you attach all the parts to the same XYZ trajectory, but don??t give any of them a name: just assign them empty brackets (""). Then, you make a transparent placeholder mesh that is _slightly_ larger than the sum of the parts, and give this one a proper name. This is the only mesh that lives through the entire mission. If you make this with a 98% transparent material, and map a 100% transparent texture to it, it will still be selectable in Celestia, but entirely invisible. Now you can exchange - and rotate - the various parts of the model simply by using beginning and ending dates. It is also, as Selden writes, very simple to create, as each part is a distinct object. The SSC file will become rather large, but very easy to read if you build it up chronologically.

- rthorvald

[ElChristou]

...I think what I'd do would be to define a dummy object (class invisible, or a ReferencePoint, or a transparent Mesh) following an appropriate trajectory, define an OrbitFrame and a BodyFrame referenced to that dummy object, and then define the motions of the various spacecraft objects relative to those Frames...

Huumm... I'm not sure this could be applicable here...
Don't forget we have several models doing several different things; example:

The 3rd stage will orbit Earth (after following a xyz for take off) then burn down in the atmosphere

The CSM/LEM will travel to the Moon

The CSM will orbit the Moon

The LEM will land on the surface

etc...

To me each sequence would use a particular reference body:

The 3rd stage -> Earth

LEM extraction -> 3rd stage

CSM/LEM travel -> Moon
(indeed this one could be breack in:
CSM -> Moon, LEM -> CSM)

CSM in orbit -> Moon

LEM Landing -> Moon
(this one could be breack in:
DS -> Moon, AS -> DS)

AS take off -> Moon

AS docking -> CSM

AS crash -> Moon

CSM travel back -> Earth

CS reentry -> Earth

SM burning -> Earth


Now, what would be more convenient, to use separated models from beginning to end of the mission or swith between grouped models and separated models? (example: the CSM/LEM could be one model or 4 models (SM, CM, DS, AS))

Perso I tend to prefer all separated models, just like reality... but won't this be a real nightmare at ssc level?

[rthorvald]

Perso I tend to prefer all separated models, just like reality... but won't this be a real nightmare at ssc level?

No. It will be a big file, but nothing compared to the filesize of your models... Complex to write, but not particularily difficult.

- rthorvald

[linuxm@n]

Perso I tend to prefer all separated models, just like reality... but won't this be a real nightmare at ssc level?

We will use something like this:

#----- Composant N?° 1 -----Head
"N1-L3-2" "Sol/Earth"
{
Class "spacecraft"
Mesh "N1-L3.3ds"
Radius 0.0224000
Beginning "1969 07 03 23:00:18"
Ending "1969 07 03 23:01:53"

SampledOrbit "N1-d?©collage.xyz"

Obliquity 45.79526
RotationOffset 132.4
Orientation [0 0 0 1]
EquatorAscendingNode 240.096681433
RotationPeriod 1.9
#LongOfRotationAxis
#PrecesionRate
#Albedo
}

#----- Composant N?° 2 -----Stage V (3)
"N1-BlokV-2" "Sol/Earth/N1-L3-2"
{
Class "spacecraft"
Mesh "Bloc-V.3ds"
Radius 0.0056400
Beginning "1969 07 03 23:00:18"
Ending "1969 07 03 23:01:53"

LongLat [ -90 0 0.0042]

Obliquity 0
RotationOffset 132.4
Orientation [0 0 0 1]
EquatorAscendingNode 0
RotationPeriod 1.9
#LongOfRotationAxis
#PrecesionRate
#Albedo
}

#----- Composant N?° 3 -----Stage B (2)
"N1-BlokB-2" "Sol/Earth/N1-L3-2"
{
Class "spacecraft"
Mesh "Bloc-B.3ds"
Radius 0.0105135
Beginning "1969 07 03 23:00:18"
Ending "1969 07 03 23:01:53"

LongLat [ -90 0 0.0195]

Obliquity 0
RotationOffset 132.4
Orientation [0 0 0 1]
EquatorAscendingNode 0
RotationPeriod 1.9
#LongOfRotationAxis
#PrecesionRate
#Albedo
}

#----- Composant N?° 4 -----Stage A (1)
"N1-BlokA-2" "Sol/Earth/N1-L3-2"
{
Class "spacecraft"
Mesh "Bloc-A.3ds"
Radius 0.0158640
Beginning "1969 07 03 23:00:18"
Ending "1969 07 03 23:01:53"

LongLat [ -90 0 0.0457]

Obliquity 0
RotationOffset 132.4
Orientation [0 0 0 1]
EquatorAscendingNode 0
RotationPeriod 1.9
#LongOfRotationAxis
#PrecesionRate
#Albedo
}

#----- Composant N?° 5 -----Flam1
"N1-BlokA-flamme-2" "Sol/Earth/N1-L3-2"
{
Class "spacecraft"
Mesh "flam-a.3ds"
Radius 0.0080000
Beginning "1969 07 03 23:00:18"
Ending "1969 07 03 23:01:53"

LongLat [ -90 0 0.067152]

Obliquity 0
RotationOffset 132.4
Orientation [0 0 0 1]
EquatorAscendingNode 0
RotationPeriod 1.9
#LongOfRotationAxis
#PrecesionRate
#Albedo
}

#----- Composant N?° 6 -----Flam2
"N1-BlokA-bigflamme-2" "Sol/Earth/N1-L3-2"
{
Class "spacecraft"
Mesh "bigflam-a.3ds"
Radius 0.0450000
Beginning "1969 07 03 23:00:18"
Ending "1969 07 03 23:01:53"

LongLat [ -90 0 0.103152]

Obliquity 0
RotationOffset 132.4
Orientation [0 0 0 1]
EquatorAscendingNode 0
RotationPeriod 1.9
#LongOfRotationAxis
#PrecesionRate
#Albedo
}


No invisible object and it works and it use separate models (works on 1.41) This file is used in my N1 ssc file just for liftoff before ejecting first stage after 120 seconds

ElCristou y have found celestia 1.5.pr?©3 for windows and find a 1.49CVS source for linux but it seems to have a serious timing probl?©m, for example liftoff began 40 second too late and the rocket is far of the launchpad.


Linuxman

[ElChristou]

Linuxm@n, this is a ssc used with 1.4.x, right?

With the latest post I'd like to know if the use of reference frames could not help a lot for what we want.

I'm not familiar with the problems of timing and position after 1.5.x but I think this has been already reported and you should find some explications digging not too far the forum...

[Fenerit]

Strangely, if I place those items following the photo and pict by Andrea some days ago, they don't match exactly the photos on ground within Celestia...

That's the proof that the landing on the moon was actually a hoax. They never got to the moon !

I agree with Cham.

[Fenerit]

Chris, what is the engine that permit the rotation of the CSM/LEM modules?

[ElChristou]

Chris, what is the engine that permit the rotation of the CSM/LEM modules?

Those trusters you can see both on the sides of the CSM and around the AS of the LEM.

[LordFerret]

Fenerit, both the CSM and LEM had attitude control thrusters (vernier).

In this picture of the CSM, they're visable on the left and right sides - the cluster of 4 cup/cone shapes.
http://www.hq.nasa.gov/alsj/a11/ap11-S69-32370.jpg

In this picture of the LEM they're more visable, again on the upper left and right sides.
http://www.hq.nasa.gov/alsj/a11/ap11-S69-19644.jpg

[Fenerit]

Well, I suppose that another one there is on the opposite side of the first photo. Nevertheless, two of the four nozzle are in a position in which the resulting force, the momentuum, to be pass across the main's propulsion as on the contrary, across the tip of the module, and with difficulty they can be able to turn about of 180 degree the module, as a tense-curved bow do not eject the arrow in a bend way. The others could serve for a turn on itself; practically to nothing. They are posites esclusively for a straight line manoeuvre, since the orthogonal combination of the two motion due to each one of the nozzle's clusters it serve much more at the same purpose that with rispect to other, because the resulting is tangential; as a rotating tense-curved bow continues in ejecting the arrow in a straight line. They are placed for obtaining an effect similar at of the scanalate drill of the guns. Only the LEM seem capable of a lateral thrust, but it manoeuvre later.
Seems that in the voyage of the man on the Moon there are educational purposes about what one can do or not do with the physics.
Untill now people has found violations in the conservation of the force, of the mass, of the quantity of motion and of the angular momentuum. Someones point out that probably all these devices were build for a planning voyage, but that this voyage it has not been realized; and that the photo in our hands sounds like a never projected film to which to have been removed and mixed the photograms.
I'm waiting for a confutation of what I've said about the nozzle.

[ElChristou]

Fenerit,

Could you use this images to trace what your are explaining above? (with my bad english I have some trouble to follow you )

To me a 180?° rotation would be the result of firing the two thrusters here:



Now you seems to know much more that I the mechanism of kinematic, so please a few more lines and circles on this pict would be welcome to explain us better your theory...

[Fenerit]

Hey Chris, the "bad english" (what ugly term is this, I prefer "not native english") is mine, not your. I'm confusing with the first photo, that in the hangar, where the thrusters I believed were three and not four, sorry. I'm very skeptical about the man on the Moon, expecially after the cinematographics art, as well as I should be doubtful about a voyage to Mars after Celestia, Bryce, Terragen, Vue, 3d Studio max, Maya and so on, but my provocations are just for conversating with someone, nothing else. But now I do not want to distract you from these fantastic works, even thought, at the present, with my Duron 750 I do not what I should can appreciate it.

[ANDREA]

Seems that in the voyage of the man on the Moon there are educational purposes about what one can do or not do with the physics. Untill now people has foundviolations in the conservation of the force, of the mass, of the quantity of motion and of the angular momentuum. Someones point out that probably all these devices were build for a planning voyage, but that this voyage it has not been realized; and that the photo in our hands sounds like a never projected film to which to have been removed and mixed the photograms. I'm waiting for a confutation of what I've said about the nozzle.

Fenerit, you say "people has found" or " Someones point out that probably" etc.
Names, please, it's too easy to cite unnamed people, but obviously, if you don?€™t give a true reference, it could be believed or not, IMHO.
Cham and Fenerit, in order to understand if you are serious or joking on the matter, just a couple of (serious) questions:
1- Fenerit, if you don't believe that the Apollo RCS- Reaction Control System, or ?€?engines?€

[Fenerit]

Andrea, for a scientific evidence there is need that an experiment to be repeteable, and I do not believe that the CCCP were unable to envoj someone on the Moon just because they holds the thermoionic tube again. It should be as the could fusion, that only the founders were able to repeat and nothing else.

[ANDREA]

Andrea, for a scientific evidence there is need that an experiment to be repeteable, and I do not believe that the CCCP were unable to envoj someone on the Moon just because they holds the thermoionic tube again. It should be as the could fusion, that only the founders were able to repeat and nothing else.

Correct, but as you know there has been a kind of scientific assault to the theory, that at the end proved faulty.
Up to now this didn?€™t happen with Apollo Moon missions (a scientists?€™ worldwide conspiracy? Hohohooo).
Fenerit, I don't try to convince you that LEM landed on the Moon, I'm only giving you evidence of "written", official, NASA scientific documents on the problem you submitted here, not reports of "people has found" or "Someones point out that probably...", as you instead have done up to now.
This only means that now you have original and official documents to study and eventually rebut, if you will be able to do it.
Please, believe me, I'm not paid by NASA to persuade you, you are obviously free to believe what you wish, but if you want persuade someone else on your opinions, you should give something more than chatters, IMHO!
Bye

Andrea

[Cham]

There is also a large conspiracy from all the scientific community making people believe that Earth is moving around the Sun. The truth is this : Earth is at the center of the universe, and all the planets and the sun are actually moving AROUND Earth. I should know, since I'M a scientist. Like others, I was also contributing to this conspiracy (it's all a matter of jobs and salary that we need to justify). I'm now telling the truth, since I cannot tolerate the conscience problems that that implies.

[Fenerit]

Andrea, for a scientific evidence there is need that an experiment to be repeteable, and I do not believe that the CCCP were unable to envoj someone on the Moon just because they holds the thermoionic tube again. It should be as the could fusion, that only the founders were able to repeat and nothing else.

Correct, but as you know there has been a kind of scientific assault to the theory, that at the end proved faulty.
Up to now this didn?€™t happen with Apollo Moon missions (a scientists?€™ worldwide conspiracy? Hohohooo).
Fenerit, I don't try to convince you that LEM landed on the Moon, I'm only giving you evidence of "written", official, NASA scientific documents on the problem you submitted here, not reports of "people has found" or "Someones point out that probably...", as you instead have done up to now.
This only means that now you have original and official documents to study and eventually rebut, if you will be able to do it.
Please, believe me, I'm not paid by NASA to persuade you, you are obviously free to believe what you wish, but if you want persuade someone else on your opinions, you should give something more than chatters, IMHO!
Bye

Andrea

Your reasoning's way it's right, but if I should can produce the same evidence of the astronaut's mission, I shoud be an astronaut, and this is false. From this follow that all men that are not astronauts could not say anything on the mission, neither that who believe in it. In this consist my "chatter" limit. But now, as I've said before, I do not intend to distract yours with further questions that are not relate with the subject of this post. Ciao e salutami Roma.