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#2226 2025-10-15 16:36:37
- SpaceNut
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- From: New Hampshire
- Registered: 2004-07-22
- Posts: 30,107
Re: Starship is Go...
What is Crunch wrap?
"Crunch wrap" is the informal name for a new material SpaceX is testing on Starship to seal gaps between heat shield tiles during atmospheric reentry. This material, often a ceramic fiber felt, is installed around each tile before it's snapped into place. After installation, the excess material is trimmed, creating a flush and sealed surface that prevents hot plasma from leaking through the gaps and damaging the underlying layers.
Why it's needed
Heat leakage: In previous flights, heat was able to seep through the gaps between the heat shield tiles, causing the underlying ablative material to burn away and creating white deposits on the hull.
Durability: The "crunch wrap" is designed to be quickly trimmed and allows the tiles to be more resistant to damage during reentry and to better withstand the stress of multiple flights without extensive refurbishment.
Rapid reusability: By improving the sealing and reliability of the heat shield, the "crunch wrap" helps SpaceX achieve its goal of making Starship a rapidly reusable vehicle.
How it works
Installation: Before a tile is mechanically attached, the "crunch wrap" material is wrapped around its sides.
Sealing: When the tile is pressed into place, the material is forced into the gaps between the tiles.
Trimming: The excess material that sticks out beyond the surface is then cut off, leaving a neat, flush seal.
Testing: This system was tested and performed well, leading SpaceX to plan on using it more extensively on future flight
Flight 11 Crunch Wrap™ TPS upgrade
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#2227 2025-10-15 17:29:45
- GW Johnson
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- From: McGregor, Texas USA
- Registered: 2011-12-04
- Posts: 6,114
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Re: Starship is Go...
In the previous post, the "kaowool" is a low-density ceramic or mineral fiber insulation. That low density means it has a low thermal conductivity, letting the tile get hotter without the tank shell seeing that heat addition so very much. You can only do that if you have a separate means of "tying" the tile in place over the insulation. In SpaceX's case, that is the tile retention pins.
That low density insulation has to be a mineral/ceramic fiber to take the temperatures at the interface with the tile. That way the tile can be a denser and therefore stronger and tougher ceramic (or other material, but apparently not iron-based from Flight 10). Denser is higher thermal conductivity, inherently. Which makes the inner tile face temperature much closer to the outer face temperature. Which is why they need the "kaowool" layer.
The "Pyron" ablative layer is not something I understand yet, except that it is the backup in case the tile is lost. It is related to PICA-X, based on what little there is to be read about it. PICA-X is what the Dragon uses for its ablative heat shield. "PICA" is an acronym for "phenol impregnated carbon ablator". The carbon is likely in a woven fabric form. This was originally a NASA thing, but it was expensive and difficult to fabricate. SpaceX subsequently did a cheaper- and easier-to-fabricate variant, and named it PICA-X. It is still phenolic reinforced with carbon fibers (likely in woven fabric form) and who knows what else, either way. I have seen no material specs for either form, much less "Pyron".
Apparently, the tiles used on Flight 10 were "metallic" in the sense of high iron content in some way. I know NOTHING about the actual material! But apparently it oxidized very fast during the one entry, quite unexpectedly. Whatever Flight 11's tiles were made of, it was something different, likely some kind of firebrick-like material. And those tiles worked a lot better.
Bear in mind that there was no insulation or backup underneath the space shuttle heat shield tiles. Those were a fragile and vulnerable low density ceramic, combining the high temperature resistance of the alumino-sililcate material and the low thermal conductivity of the very low density, into a single material. The new nose and leading edge tiles on X-37B are the first step away from that approach, they being a high-density ceramic locked onto a low-density ceramic underlayer. SpaceX seems to be pioneering yet a different approach. And it would seem to be working.
GW
Last edited by GW Johnson (2025-10-15 17:49:36)
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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#2228 2026-01-03 15:21:58
- SpaceNut
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- From: New Hampshire
- Registered: 2004-07-22
- Posts: 30,107
Re: Starship is Go...
starship is the only ship planned to go to mars.....Nasa is not, GW ships need builders and that not happening in current culture.
Even Bezo is finding that out...
If you do not know the mass we are sending then you are not going but for a show that we can do so and then stopping maybe never going again
SpaceX's Starship is the leading vehicle currently in development for human missions to Mars, designed as a fully reusable system to carry large crews and cargo, with plans for initial cargo flights by 2030 and human landings potentially in the late 2030s. NASA and other agencies are also developing concepts, often involving elements like the Orion spacecraft for Earth return and potential Deep Space Habitats, but Starship is the most prominent contender for the actual transit and landing.
SpaceX Starship
Concept: A massive, fully reusable rocket system (Super Heavy booster + Starship upper stage) designed for interplanetary travel, including Mars colonization.Capabilities: Can transport up to 150 metric tonnes (fully reusable) or 250 tonnes (expendable) to orbit, significantly more than any current rocket.
Mars Approach: Uses aerodynamic braking for entry into Mars' atmosphere and a powered vertical landing, similar to its Earth landings.
Timeline: SpaceX aims for the first cargo flights to Mars around 2030, with human missions following, possibly in the late 2030s.
NASA & Other ConceptsOrion & Deep Space Habitats: NASA's potential approach involves using the Orion capsule for crew transport to Mars orbit, paired with a separate Deep Space Habitat for the long journey.
Design Reference Missions (DRMs): NASA has studied various concepts, including nuclear thermal and solar electric propulsion, for efficient Mars transit.
Project Orion (Historical): An ambitious, but discontinued, 1960s project exploring nuclear pulse propulsion for massive Mars payloads.
Key Challenges for Mars Ships
Long Duration: Missions take many months, requiring robust life support and radiation protection.
In-Orbit Refueling: Starship needs to refuel in Earth orbit to have enough propellant for the Mars journey.Reliable Landing: Safely landing such a large vehicle on Mars is a significant technical hurdle.
In essence, SpaceX's Starship is leading the charge with a singular, reusable vision, while NASA and international partners focus on multi-component systems and gradual technological development for future human expeditions
For SpaceNut .... Your posts today look interesting and i'll go back to read them again more slowly ... I'm here to post an update on the OpenFOAM run that just ended.
I was ** really ** happy to see Calliban back in the mix today! The weekend is ahead. Perhaps we'll be lucky and win a bit more of his time.
We won't be hearing from GW for a while. He has ** two ** clients in hand and one in the bush! Plus the 50th Anniversary is coming up January 10th.
I had a chance today to think about our situation with the garage. It seems to me we haven't seen Capitalism at work yet, with the sole exception of SpaceX, which is driven by obsession and not by market forces.
It is possible that we have members who do not understand how Capitalism works.. Every once in a while a post shows up that makes me wonder.
We've been talking about a garage for equipment on Mars, and the idea of sizing a building based upon equipment that does not exist and therefore doing nothing is an example of the opposite of Capitalism. It might be an example of Big Government thinking.
Capitalism builds products people don't know they want, and then convinces them they want those products.
In this case, we already have a large and vibrant industry building prefabricated buildings for every conceivable purpose.
The idea of waiting to see what equipment shows up on Mars before building a maintenance facility is NOT the Capitalist way.
In my opinion, GW's rocket designs are quite likely to be superior to Elon's in every possible way, simply because they are designed for Mars, and not intended to be a one-size-fits-all concept. I suspect you have never read a word of GW's work. If you ** did ** read it, it made no impression, because you seemed to think Elon is the only human alive who can put people on Mars safely.
The only reason Elon is in the race is because he is a man obsessed. There is no economic justification for trips to Mars. If Elon succeeds, the economic case will happen automatically, because all the doubters will suddenly find money to invest.
(th)
I can not disagree there but its is about the $$$ he can get along the way. Bezo may catch up yet but he is learning the government process.
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