Wiki Super Heavy/Starship - General Development Discussion

[JB47394]

First the additional stringers on the S26, now new weld marks on B10:

I assume there were no equivalent marks for the methane tank. If so, I'm guessing the downcomer is somehow serving the function of the internal baffles in the LOX tank. Either preventing voids or softening the hydraulic hammer effect. Then again, there may not be enough LCH4 in the tank to produce a large enough hammer effect to cause problems. There's almost four times more LOX onboard by mass.

 

[bxr140]

^I wonder how much extra weight these reinforcements will add? Perhaps not enough to affect the payload capacity.

The good news is that the iterative nature of SX allows them to decouple “get it right” with “get it light”, so they're likely not concerned about impact to payload capacity right now for the various day on day tweaks.

 

[ecarfan]

In the world of orbital class rockets, every kg makes a difference.

 

[JB47394]

For you material scientist geeks. He attempts to create his own Shuttle tile, and then compares a sample of a Shuttle tile with a sample of a Starship tile.

 

[Grendal]

For you material scientist geeks. He attempts to create his own Shuttle tile, and then compares a sample of a Shuttle tile with a sample of a Starship tile.

Since you brought up TPS and PICA, this lets me bring in this incredible video I've posted before of NASA's Dan Rasky working with SpaceX.
I highly recommend the full interview of Dan on Youtube: COTS: Dan Rasky

 

[ecarfan]

Yep, that is a non-trivial operation to get those pins placed properly.

 

[scaesare]

Yep, that is a non-trivial operation to get those pins placed properly.

View attachment 1020598View attachment 1020599

Are those tiles being attached with pins or glued on? They don't seem to be visible in that pic... Are they attached in individual sets for each tile and that's why they aren't visible?

We've seen pins attached ahead of tiles before:

 

[mongo]

Are those tiles being attached with pins or glued on? They don't seem to be visible in that pic... Are they attached in individual sets for each tile and that's why they aren't visible?

We've seen pins attached ahead of tiles before:

View attachment 1020778

The replied to image was of the lifting jig pins being installed into the ship, not tile pins. (Unless you were talking about plugging the hole?)

 

[scaesare]

The replied to image was of the lifting jig pins being installed into the ship, not tile pins. (Unless you were talking about plugging the hole?)

Ah... my bad. Misunderstood... thanks.

 

[mongo]

SpaceX asking FAA for permission to launch nine times in 2024.
H/t Sawyer
SpaceX seeks a waiver to launch Starship “at least” nine times this year

 

[JB47394]

SpaceX asking FAA for permission to launch nine times in 2024.
H/t Sawyer
SpaceX seeks a waiver to launch Starship “at least” nine times this year

For anyone who thinks the government is dragging out the approval process, read that article for a taste of the government view. The FAA needs men.

 

[ecarfan]

For anyone who thinks the government is dragging out the approval process, read that article for a taste of the government view. The FAA needs men.

From that article:

Coleman said that when he joined the Commercial Space Transportation arm of the FAA in 1996, the organization had 40 employees. A decade ago, there were 73. Now there are 143, and the organization is "aggressively" seeking to grow to 157 staffers in Florida, California, Texas, and Washington, DC.

"Right now, we're at about 140 people, and they're pedaling as fast as they can," he said. "We're working on the weekends. We're working late into the night. We do need additional staff."

Given that the current House majority does not believe that government has an important role to play in regulating public health and safety, the FAA is not going to get a budget increase that will allow it to hire more people. So the FAA has to figure out how to make the current launch certification process more labor efficient.

 

[Grendal]

Are those tiles being attached with pins or glued on? They don't seem to be visible in that pic... Are they attached in individual sets for each tile and that's why they aren't visible?

We've seen pins attached ahead of tiles before:

View attachment 1020778

Ah-ha! I think this picture gives an example of the "tiles falling off" solution. The tiles were not the best way to attach to the pins. That new white material is probably much more porous, flexible, and sticky type of foam. I expect it will do a much better job of staying attached during the energetic ascent and descent in atmosphere.

 

[scaesare]

Ah-ha! I think this picture gives an example of the "tiles falling off" solution. The tiles were not the best way to attach to the pins. That new white material is probably much more porous, flexible, and sticky type of foam. I expect it will do a much better job of staying attached during the energetic ascent and descent in atmosphere.

I honestly don't know how recent that pic is and if that's a new attachment solution....

 

[Grendal]

I honestly don't know how recent that pic is and if that's a new attachment solution....

Even if it isn't "the most recent solution," I think it is the strategy to the correct solution. It would just be what material would be porous, flexible, and sticky enough to prevent the tiles from falling off.

 

[mongo]

Ah-ha! I think this picture gives an example of the "tiles falling off" solution. The tiles were not the best way to attach to the pins. That new white material is probably much more porous, flexible, and sticky type of foam. I expect it will do a much better job of staying attached during the energetic ascent and descent in atmosphere.

Are we talking about the fluffy fiberglass style insulation?
CTE and temperature differential means they need compliance between tiles and ship. Critically strong pins with stand off gap provide that.

 

[JB47394]

That new white material is probably much more porous, flexible, and sticky type of foam.

I believe that's just the backing that has always been used. They apply it in big sheets over the pins, then the tiles go over that.

The Shuttle tiles were glued to a felt-like material termed strain isolation pads (SIPs) and then that was glued to the Shuttle structure. The glue was room temperature vulcanizing (RTV) silicone adhesive.

 

[Grendal]

Are we talking about the fluffy fiberglass style insulation?
CTE and temperature differential means they need compliance between tiles and ship. Critically strong pins with stand off gap provide that.
View attachment 1020888

Yes. I'm pretty sure that the original way was to put the tiles directly on the pins. The TPS is a foamy material and could be attached but the foamy aspect is very rigid. Any strong vibration and energetic movement could easily cause them to pop off or even break. If you have a material that can stay attached to the pins in the most extreme situations then that would be a winning strategy for SpaceX.

 

[spacerfc]

From that article:

Given that the current House majority does not believe that government has an important role to play in regulating public health and safety, the FAA is not going to get a budget increase that will allow it to hire more people. So the FAA has to figure out how to make the current launch certification process more labor efficient.

That's not it exactly. If you read the recent GAO report on FAA AST, they're having trouble filling the positions that are already authorized by Congress, because they have to compete with private industry for experienced people. For example they lost two inspectors to private companies recently.

 

[ecarfan]

So the FAA can’t find staff because they don’t have the budget to pay a competitive salary. And that budget is provided by….Congress.