Skylab 1973 rebuild

[TheShuttleExperience]

Nice project

Silly question: was the ATM actually built out of an existing structure of a Lunar Module's descent stage?

 

[Urwumpe]

Exactly. But Skylab mostly used gyroscopes or reaction wheels to rotate, which are much slower than even the weak RCS of skylab. Thats why giving the telescopes their own motion beyond rotation makes sense.

 

[gattispilot]

Nice project

Silly question: was the ATM actually built out of an existing structure of a Lunar Module's descent stage?

Thanks. No sure
yes. Skylab used Rcs and reaction wheels. So are you saying to have both and a key to change them. But animation are the same.

 

[Urwumpe]

yes. Skylab used Rcs and reaction wheels. So are you saying to have both and a key to change them. But animation are the same.

Yes. Just look into the planned flight plan, page 49.

https://www.ibiblio.org/apollo/Documents/46377138-Reference-Skylab-Flight-Plan-SL-1-SL-2-SL-3-And-SL-4-April-30-1973-SL-1-Launch.pdf

 

[gattispilot]

So a key to switch between reaction wheels and rcs?
but the aiming is going to be yond me. I know the ISS has reaction wheels so I might be able to reuse the code.

But right now I want to get the animations and mesh correct.

 

[Urwumpe]

Could help conserving fuel for attitude control at least, but I am not sure if its only done manually or if the APCS was able to control the use of RCS itself.

 

[gattispilot]

Views of the interior with hatches open.
And pop out box. I might do 2 pop on boxes. One just for EVA and the the other for ATM

I will look about adding the reaction wheels. BUT it would be up to the user to move towards the sun

 

[n72.75]

The Skylab RCS is just compressed N2. not very powerful, and there isn't much of it.

Most of the pointing is done with the reaction wheels or the attached CSM. The Skylaab CSM even has programs dedicated to docked alignment, maneuvering and burns, while attached to Skylab.

 

[gattispilot]

Thanks. I can add rcs thrusters. I can try the reaction wheels. But the aiming program not sure about.

 

[PDF]

I have been asked about Skylab. I am using Skylab 1973 mesh with permission. I am working on an interior. But I am struggling with fitting an interior into the exterior.


BUT the interior does not follow that. Being the grid on the floor is rotated slightly off center. I can build it like that. When looking down the grid will be off.

The airlock module has 4 small windows they are 37.5 degrees off center.

In the mesh the texture of the MDA is wrong as it has the windows at the docking end.

Awesome

 

[gattispilot]

There are things that might be nice. There were 3 extendable booms. Not sure if they wer attached the ship. I think so. As the control for them was attached to the bay?

There was a light on the sunshield end for eva.

 

[Urwumpe]

Thanks. I can add rcs thrusters. I can try the reaction wheels. But the aiming program not sure about.

If you need help, just ask, I'll try my best to help you.

For the aiming, you just need to define a control loop to minimize attitude errors for all three axes. The thrusters or CMGs could then be triggered by a simple fuzzy logic function.

Likely not realistic at all, but enough for the task, also you could then simply switch the attitude modes by providing different sources for the attitude error, eg: Suntracker vs inertial.

 

[Urwumpe]

@gattispilot Maybe this is interesting for you, I found a performance report of Skylabs attitude control system, which also describes the coarse structure of it:

https://ntrs.nasa.gov/api/citations/19750016749/downloads/19750016749.pdf

The APCS portion controls the station attitude, the EPCS controls the telescope angles.

 

[gattispilot]

Thanks. RCS can be added. just need the thrust level and fuel level. The CMG can be added. But the pointing,.... I will need help on it.

It looks like the thrusters are at the aft end?



Still looking at the extendable booms

 

[Urwumpe]

Yes. that is correct. Also the RCS "fuel" is VERY limited, especially for a space station.


The extensible booms are manually operated by the EVA astronauts, AFAIR.

 

[gattispilot]

SO only 2 sets of thrusters at the aft ?

Also for details needs to redo the canister.

 

[Urwumpe]

Yes. Do you need more? Six thrusters for three axes...

https://ntrs.nasa.gov/api/citations/19710007043/downloads/19710007043.pdf

 

[gattispilot]

Thanks. I just need to add them to the mesh. It looked like different thrust levels. 222N 89N 44N.
Impulse 271 x10 5 N-sec

 

[Urwumpe]

Thanks. I just need to add them to the mesh. It looked like different thrust levels. 222N 89N 44N.
Impulse 271 x10 5 N-sec

Yes, Its different to the APS of the SIVB stage, but installed in the same place. On the Skylab B photographs on Wikipedia, you can find the TACS thrusters on some OWS photographs of the museum piece.

 

[gattispilot]

So the rcs thruster are on the mesh.
from the original sc3 code:
FUEL_MASS=700 ATTITUDE_THRUST=10675 ;TACS - 10,675 Newtons at 1 meter from CofG = two 444.8N thrusters at 12 meters ISP=15098 ;TACS - 99,000 lb-sec = 440,374N-sec total impluse / 444.8N thrust = 990 sec

Confused.

I think I have the Can reversed/mirrored/90 degrees out?

We know the Canister has 8 sides. Side 1 is where the notch and ladder are. Side 2 is the center station. We know the can can rotate 120 degrees +/- . And that this is so you have access to the film in S052, s054,s056, H1. But how it seems they are on the other side?

in the drawing of the canister it looks like the film cutdoor door is by the S055a and H1