totm nov 2023 SpaceX Discussion Thread

[StrandedonEarth]

Huzzah! to SpaceX for another successful launch and landing....

...and a bigger HUZZAH!! for making this seem routine and boring. 

Oh right, if we want groundbreaking excitement, keep an eye on Boca Chica.... Hopefully things there will eventually seem boring and routine. Huzzah 

[kerbiloid]

They can make

Spoiler

pictures out of tiles

 

Edited March 11, 2021 by kerbiloid

[tater]

 

[RyanRising]

I wonder why  we don't get to see the inside of the tank more often, especially during the second stage burn. It'd make a nice addition to looking at the engine bell, anyway.

[sevenperforce]

So this is the best leg design I've been able to come up with so far.

It solves some of the biggest challenges overall:

• No seam in the heat shield, just a heat shield blister as depicted in the #dearMoon concept art
• No break, slot, or hole in the skirt
• Load path passes through the same skirt mounting points where it attaches to Superheavy
• Fully stable in the roll axis (no risk of buckling)
• Widest possible footpad area for landing on Martian (or even lunar) regolith
• Fairly minimal volume used inside skirt
• Fully self-leveling and shock-absorbing; can accommodate multiple piston failures
• All load-bearing actuators take purely vertical loads

The only thing I'm unsure about is the actuation of the rotation. That actuation doesn't take any load (it can lock out like the current legs) and so the actuator can be extremely small; I'm just not quite sure where to put it.

Spoiler for full-size image and legend.

Spoiler

A: Fully stowed position; can be covered by heat shield blister fairing on the windward side
B: External pistons extend to push the leg clear of the heat shield
C: Rotation to landing position (again, actuation here may be a little tricky)
D: Inner pistons extend to brace between footpad and skirt
E: All four pistons self-level and provide shock absorption

EDIT: Here's a possible actuation:

 

Edited March 11, 2021 by sevenperforce

[Flavio hc16]

1 hour ago, sevenperforce said:

So this is the best leg design I've been able to come up with so far.

It solves some of the biggest challenges overall:

• No seam in the heat shield, just a heat shield blister as depicted in the #dearMoon concept art
• No break, slot, or hole in the skirt
• Load path passes through the same skirt mounting points where it attaches to Superheavy
• Fully stable in the roll axis (no risk of buckling)
• Widest possible footpad area for landing on Martian (or even lunar) regolith
• Fairly minimal volume used inside skirt
• Fully self-leveling and shock-absorbing; can accommodate multiple piston failures
• All load-bearing actuators take purely vertical loads

The only thing I'm unsure about is the actuation of the rotation. That actuation doesn't take any load (it can lock out like the current legs) and so the actuator can be extremely small; I'm just not quite sure where to put it.

Spoiler for full-size image and legend.

  Hide contents

A: Fully stowed position; can be covered by heat shield blister fairing on the windward side
B: External pistons extend to push the leg clear of the heat shield
C: Rotation to landing position (again, actuation here may be a little tricky)
D: Inner pistons extend to brace between footpad and skirt
E: All four pistons self-level and provide shock absorption

EDIT: Here's a possible actuation:

 

thisa seems actually a very good design. the actuation/rotation might even be passive with a bit of weight and design thinkering

[RCgothic]

I don't like the heat shield contacting regolith tbh.

[tater]

47 minutes ago, RCgothic said:

I don't like the heat shield contacting regolith tbh.

I assume the leg fits under the bulge, which is removed to show it.

[Brotoro]

I assumed that as well. I'd worry about that big thin plate getting bent on landing in such a way that it couldn't retract for the trip back to Earth.

[sevenperforce]

1 hour ago, RCgothic said:

I don't like the heat shield contacting regolith tbh.

@tater — is right, this shows the leeward side for the sake of detail. On the windward side, the footpad will be covered by the heat shield in the stowed position. I suppose the lee side could be covered by a stainless steel fairing if needed but I doubt it is needed.

This whole design is intended to allow the footpad to slide down vertically, out from under the heat shield, and then rotate to meet the ground.

[tater]

 

[RCgothic]

SN11 was cryo-proofed last night and tested RCS thrusters, clearing the way to static fire.

Apparently they've changed some of the venting locations for this prototype as well.

 

 

 

[RCgothic]

BN1 is in stack up:

 

 

 

Edited March 12, 2021 by RCgothic

[Spaceception]

I wonder what the test objective will be. Will they semi-replicate SN5/6 and Star/Grasshopper, and go a couple hundred meters up and down just to feel things out? Or will they go a bit more downrange, shut off the engines, and turn around for landing, given that Starship has done some more ambitious flights already? Iirc, the thrust puck has room for 4 raptors, and 2 could be used for landing.

[RCgothic]

I think getting authorisation for BN1 to significantly depart from the airspace over the site may be a challenge at this stage.

I'm betting pretty much straight up and down again. But it could be to 10km rather than 150m SN5/6 style.

Edited March 12, 2021 by RCgothic

[RealKerbal3x]

Just now, RCgothic said:

 

I'm betting pretty much straight up and down again. But it could be to 10km rather than 500m SN5/6 style.

SN5/6 flew to around 150m, same as Starhopper. But yeah, a low altitude hover and translation over to the landing pad seems most likely.

[RCgothic]

Orbital Launch Tower pilings are now visible:

 

 

 

[kerbiloid]

Pipes.
Vertical pipes.

Finally they found the way to land it gently...

Spoiler

 

 

Edited March 12, 2021 by kerbiloid

[Brotoro]

If they plan on snagging the SuperHeavy out of the air with launch tower arms upon landing, I would think that they need to start with some low altitude, hop-up, move-over, hover-into-the-tower-arms kind of thing.

unless they plan to outfit the first SH prototype with landing gear of some sort.

[RCgothic]

They didn't quite get to static fire today.

 

[magnemoe]

3 minutes ago, Brotoro said:

If they plan on snagging the SuperHeavy out of the air with launch tower arms upon landing, I would think that they need to start with some low altitude, hop-up, move-over, hover-into-the-tower-arms kind of thing.

unless they plan to outfit the first SH prototype with landing gear of some sort.

The arm catch is down the lane, sometime between the Mars invasion fleet and P2P. 
Musk dream large and he like that the fans solves problems for him. 
Now I say making every other launcher obsolete is an high enough bar, no first stage reuse will not enough in most cases. 
And they launched 2/3 of the mass to orbit last year. 
 

[kerbiloid]

Spoiler

The arm catching requires Breaking Ground, and would bring a DLC dependency.

So, they try to avoid it.

 

[RCgothic]

I don't think tower catch is going to be that difficult really. Hover by the tower and have multiple redundant arms grab some passive grab targets. It's nothing Boston Dynamics couldn't do in their sleep.

Might take SpaceX a few tries to catch up, but it's neither impossible nor infeasible.

[tater]

 

 

[RCgothic]

Looking forward to flight nine!