Project SpaceX SuperHeavy

Kyle

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SpaceX seems to just be calling it "LC-39A" with no distinguishing nomenclature between the two pads. But yes, normal nomenclature should indicate that this is technically LC-39D.
 

BrianJ

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Hi,
does anyone have any current info about RCS on the SuperHeavy booster 7? (Is it going to have any?)
For some reason I am wondering about these cowls/nozzles seen mid-way up, either side......
sh_rcs.jpg
Maybe just vents?
I remember Elon dropping a few hints/comments a while ago, but I can't find a darn thing with google now.
Many thanks,
Brian
 

BrianJ

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This would be useful for Starlink deployment scenarios!
Interesting! A satellite slot dispenser!
Thing is I can hardly keep up with current developements at SpaceX - let alone future plans.
If anyone wants to mod my Starship stuff, go ahead :)
 

diogom

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Hi,
does anyone have any current info about RCS on the SuperHeavy booster 7? (Is it going to have any?)
For some reason I am wondering about these cowls/nozzles seen mid-way up, either side......
View attachment 29940
Maybe just vents?
I remember Elon dropping a few hints/comments a while ago, but I can't find a darn thing with google now.
Many thanks,
Brian

I think the latest on that is the Everyday Astronaut tour a couple of months back (Part 1 being the most relevant). IIRC, RCS is 100% tank vents of excess gas, so is the Ship. In recent testing there's been those two vents (probably another pair around the back, not sure now), and 4 near the grid fins, 90 degrees apart.
 

BrianJ

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I think the latest on that is the Everyday Astronaut tour a couple of months back (Part 1 being the most relevant). IIRC, RCS is 100% tank vents of excess gas, so is the Ship. In recent testing there's been those two vents (probably another pair around the back, not sure now), and 4 near the grid fins, 90 degrees apart.
Thanks! I shall go and recheck the Everyday Astronaut vid for clues and see if I can find the relevent testing vids.
 

diogom

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As far as the vents go, I guess best is shortly after the static fires, when they depress and open them all. Not sure all would be used as RCS though.
 

BrianJ

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As far as the vents go, I guess best is shortly after the static fires, when they depress and open them all. Not sure all would be used as RCS though.
Ah! Yes, that's what I wanted to see.
Looks like 4 at the top for pitch/yaw. They're not on my add-on X/Y axes - so that makes things more interesting from a add-on-logic perspective :)
I'm guessing the two groups of 2 each side are for ullage - they are angled slightly so might be a little help with roll.

Also, it seems they already building the starlink slot-dispenser configuration for the Starship!

I better get busy :coffee:

Cheers,
BrianJ
 

BrianJ

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Updated to v.220908

Increased number of engines on 1st stage to 33.
Tweaked ascent program and 1st stage fuel reserve estimation.
New "pitch down-up" maneouvre for stage separation rotation in ascent program.
1st stage improved aerodynamics, new RCS system, roll control now mainly by aerodynamic control surfaces (Grid Fins), tweaked descent/landing autopilot guidance.
New docking port position for back-to-back docking Starship/Tanker.
Some mesh modifications.
etc.
 

Marijn

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Hi Brian,
After a few months I am getting back into flying the Starship. My first landing attempt was succesful. But I ran out of fuel just meters before catching. The arms did slide down fast and it caught the ship anyways barely above ground level. Close call..

Question: At what moment should the Reserve Landing Fuel be activated? What I am doing now is dumping any remaining main fuel at alt=120km and then activate the reserve fuel. This method seems to leave just not enough fuel. I can remedy this by activating the Reserve fuel a little bit later and have the RCS during reentry use the main fuel and dump and switch halfway during the reentry. Maybe it would be nice to have the user set the amount of reserve fuel? I think 25.5k would do it. But 25k seems not enough.

And one tiny thing. I noticed the ground speed isn't displayed in the bottom line on the Reentry view. Not that I need it, but it seems missing now.

Thanks for your great work!
 

BrianJ

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Hi,
I guess I generally leave a bit of fuel (2T) in the main tanks to cover reentry RCS use, then switch over to reserve at the start of "Skydive-Backflip-Land" sequence. But I think it might be more sensible to include enough fuel for the reentry RCS in the reserve. I'll take a look. Thanks!

EDIT:The RCS usage during reentry is a LONG way from optimal, maybe I can make it more efficient.

I can put a horizontal groundspeed readout on the HUD, no problem.

Cheers,
Brian
 

Marijn

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Ok, I'll keep between 2.5 and 6T before the reentry and activate the reserve fuel when it goes into skydive mode. That works.

I have a problem with docking now with the new docking ports. I used Pursuit MFD before, but now the ship has to pitch 180 degrees. I haven't been able to figure out how to do that. Any suggestions? Have you tried this MFD for docking?
 

Marijn

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Hi Brian,
I think the idea of SpaceX is to launch multiple tankers first and have one of them serve as the main fuel depot. Then the crewed Starship is launched last and docks only once with the deposit tanker. Therefore, I've been trying to dock two Tankers.

Docking is very hard now. When docking manually with the standard Docking MFD, some axis seem reversed which makes it very tedious at best. Using Pursuit MFD, the only method I've found now is to engage the prograde autopilot in one Tanker and then in the other Tanker disable Pursuit MFD's attitude control and take care of the attitude control manually, which is tedious as well. I didn't experience these problems with the back-to-back docking. Maybe the pitch orientation of the docking port needs to be reversed?

When transferring fuel, I don't seem to be able to select the tanks I would like (main fuel, landing reserve fuel and payload fuel). I can only select the main- and landing fuel of the other Tanker, but when I select the main the fuel is actually transferred to the payload fuel. The screenshot shows how the payload fuel is exceeding the maximum level of 125000 because it wass already full to begin with, which I don't think can be right.

orbiter_fuel_payload.png

Thanks for your time.
 

BrianJ

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Hi,
thanks for the testing and reports (y)
Just FYI, the docking port parameters are:
Pos 0, 4.545, 0
Dir 0, 1, 0
Rot 0, 0, 1
I must confess I haven't tried a full rendezvous-docking yet - just made sure it worked from a "station-keeping -> docking" situation. In theory, it shouldn't be any harder to dock Starship->Tanker than it is to dock Shuttle->ISS. But of course, there are no visual helpers (at the moment) since I have no idea what the Starship/Tanker docking mechanism would look like.

I'll give it a try with PursuitMFD and see if I can think of any way to make docking less tedious. I don't think changing the docking port orientation is going to help (unless someone can see a way that it would - please let me know!).

I had not thought about Tanker->Tanker refuelling. I'll see if I can find where that bug is.

Thanks again,
Brian
 

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Ok. I was able to transfer fuel into the main tank now. And also from Tanker_1 payload fuel into Tanker_2 payload fuel and from there back to Tanker_1 main fuel.

I see now the the max payload fuel is 170000. Then there's no issue I think with that.
 

Marijn

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It would be practical if you could select a 'From' tank, being either the main-, reserve- or payload fuel tank. That would allow for a scenario where the Starship only has do dock once.
 

BrianJ

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It would be practical if you could select a 'From' tank, being either the main-, reserve- or payload fuel tank. That would allow for a scenario where the Starship only has do dock once.
I agree. Let me have a think about the best way to do that.
 

BrianJ

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Here y' go :)

Update v.220923

Now able to select Tanker source tank for fuel transfer (Payload or Main).
Horizontal groundspeed displayed in HUD reentry data.
Mechazilla animation/attachment position bug fixed (I hope).

Cheers,
Brian

P.S. I couldn't get PursuitMFD to work for docking - I'm not sure if I'm operating it correctly, but the results seem strange.
I don't know what the problem is - RCS too weak? I set the PursuitMFD linear and rot rates pretty low but it seems to disregard them. I'll check the docking port definition code again but I don't think its that.
Any ideas?
 
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