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The big problem with Starship right now looks to be the heat tiles - I don't think they've had a single test where they haven't had some pop off, and I'd be wil

by XorNot 5y ago

The big problem with Starship right now looks to be the heat tiles - I don't think they've had a single test where they haven't had some pop off, and I'd be willing to bet the internal redesign that was announced is to stiffen up the hill to deal with flex (since it seems to be trading a little of internal diameter to do it - willing to bet that's too deepen some bracing members).

chasd00 5y ago
As soon as I saw the tiles I thought “oh no”. They’re so fragile, they have to be a major hurdle for reusability. During the everyday astronaut interview Elon is talking and then looks over at a worker smacking a tile trying to get it to stay in place. Elon whips out his cellphone and then the interview cuts to a different scene. I imagine the amount of curse words being yelled into that cellphone would not pass YouTube’s guidelines. The heat tiles suck.
ncmncm 5y ago
The main problem with the tiles is that they are the same design as on the space shuttle, which had to all be individually rejiggered on each flight: take it off, squirt in some fresh goo, stick it back on. They won't be making any 8-hour turnarounds doing that. The tiles they have are a design that is known to work, and will suffice to prove that the vehicle can get to orbit and come back in one piece. So they will need a new design that doesn't need so much detailed attention after every flight. They have years to work out what that will be, because they are much farther from ready than some, apparently many, imagine. The gross, visible, easy stuff is mostly in place. The hard stuff you can't see is still to come.
- KiwiJohnno 5y ago
  Not quite. Each tile has a socket in the middle of the back, which goes over a mounting post which is welded to the steel hull of starship. Also, there are very few different shapes of heat tiles, and the vast majority of the heat tiles are of exactly the same design and shape. On the space shuttle few, if any heatshield tiles were the same. They were individually manufactured, instead of bulk manufactured to a common specification as SpaceX are doing. Obviously that is going to be far, far more efficient. Yeah, they have had problems with tiles coming off during static fires. Although this seems to have been getting better, and it remains to be seen how bad an issue losing a few patches of single tiles actually is. Under the tiles the structure is stainless steel, while with the space shuttle it was aluminum which is clearly not as tolerant of the extreme heating of re-entry.
  - ncmncm 5y ago
    On STS, exactly zero of the tiles were the same as any other. Many but far from all had a (1) mirror image piece, on the other side, which was really no help. The SS tiles can be, and so are, much thinner than STS tiles because of the steel backing. But losing a tile might, too, not be fatal. The issue is not the shapes or even how to keep them attached during hypersonic flight. The immediate problem is that they require personal attention to each and every tile, after each flight, before they are ready to be re-used. SpaceX engineers are strongly motivated to come up with a system that does not require such treatment, but that does not mean they will get it soon. Or ever. Probably they will be trying to come up with a ceramic-fiber fabric covering that could be peeled off and replaced quickly. It would still need babying, but the vehicle would not need to be there all the while, as with the tiles.

by XorNot 5y ago

chasd00 5y ago

As soon as I saw the tiles I thought “oh no”. They’re so fragile, they have to be a major hurdle for reusability. During the everyday astronaut interview Elon is talking and then looks over at a worker smacking a tile trying to get it to stay in place. Elon whips out his cellphone and then the interview cuts to a different scene. I imagine the amount of curse words being yelled into that cellphone would not pass YouTube’s guidelines. The heat tiles suck.

ncmncm 5y ago

The main problem with the tiles is that they are the same design as on the space shuttle, which had to all be individually rejiggered on each flight: take it off, squirt in some fresh goo, stick it back on. They won't be making any 8-hour turnarounds doing that. The tiles they have are a design that is known to work, and will suffice to prove that the vehicle can get to orbit and come back in one piece. So they will need a new design that doesn't need so much detailed attention after every flight. They have years to work out what that will be, because they are much farther from ready than some, apparently many, imagine. The gross, visible, easy stuff is mostly in place. The hard stuff you can't see is still to come.

KiwiJohnno 5y ago
Not quite. Each tile has a socket in the middle of the back, which goes over a mounting post which is welded to the steel hull of starship. Also, there are very few different shapes of heat tiles, and the vast majority of the heat tiles are of exactly the same design and shape. On the space shuttle few, if any heatshield tiles were the same. They were individually manufactured, instead of bulk manufactured to a common specification as SpaceX are doing. Obviously that is going to be far, far more efficient. Yeah, they have had problems with tiles coming off during static fires. Although this seems to have been getting better, and it remains to be seen how bad an issue losing a few patches of single tiles actually is. Under the tiles the structure is stainless steel, while with the space shuttle it was aluminum which is clearly not as tolerant of the extreme heating of re-entry.
- ncmncm 5y ago
  On STS, exactly zero of the tiles were the same as any other. Many but far from all had a (1) mirror image piece, on the other side, which was really no help. The SS tiles can be, and so are, much thinner than STS tiles because of the steel backing. But losing a tile might, too, not be fatal. The issue is not the shapes or even how to keep them attached during hypersonic flight. The immediate problem is that they require personal attention to each and every tile, after each flight, before they are ready to be re-used. SpaceX engineers are strongly motivated to come up with a system that does not require such treatment, but that does not mean they will get it soon. Or ever. Probably they will be trying to come up with a ceramic-fiber fabric covering that could be peeled off and replaced quickly. It would still need babying, but the vehicle would not need to be there all the while, as with the tiles.