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SpaceX Starship - IFT-5 - Starbase TX - Pre-Launch Preparations Thread
- Thread starter JB47394
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Also from that stream, Elon said they will put an ablative secondary structure underneath the tiles just in case tiles fall off, and they have new tiles that are twice as strong all for the next ship.
I wish he had been clearer on what “strong” meant in that context. Stronger attachment points? Stronger tile material? Both? Do the new tiles weigh more? And how are they going to attach the new ablative pieces?
Removing all 18,000 tiles from Ship 30, one at a time. The thumbnail shows the nose, but most of the video is guys slowly removing the tiles. They break into the tiles at the mount points, then detach the tiles from each point. The ones mounted with adhesives look awful to remove.
Fortunately, they have a lot of guys working on it and have made good progress.
Then they have to put the ablative backing material and the new tiles back on. I hope they get to use the robot installer with the new tiles.
Fortunately, they have a lot of guys working on it and have made good progress.
Then they have to put the ablative backing material and the new tiles back on. I hope they get to use the robot installer with the new tiles.
Wow, what a huge job that is. Seems like some care has to be taken to not damage the mount points?
Hard to imagine that ship will be ready to fly in a month.
Hard to imagine that ship will be ready to fly in a month.
They should not have put the tiles in until IFT4 mission was complete.
Easy to say in retrospect... but at the same time if they operated in such a sequential manner with everything, we probably wouldn't be where we are today...
But they do know that reentry survival and tiles performance is THE unknown and the main focus for IFT4.
So why not wait till the test is completed before loading up on the tiles, while the rest of the ship can be built fully? It is also true and well understood that removing tiles is a laborious sticky operation. So I don't believe it takes a lot of foresight to make the decision to wait for the results of IFT4 to come through before installing the tiles. Hubris..
Multiple possible reasons:
- They thought the most recent attachment mechanisms would suffice
- The ablative underlayment option was conceived/developed after the ship was tiled
- They anticipated needing more data, but got sufficient data from IFT-4
- Etc...
SpaceX is not one to not press forward, even if that means needing to reverse course a bit and change directions...
Ship 30 was stacked in August 2023. Many moons ago.
In general, the idea of delaying work because of doubts is a slippery slope.
Our current tiles may not work out, so let's not put any more of them on ships. We'll want to mount a different kind of tile.
Mounting on pins may not work, so let's not put the mounting pins on ships. We'll want to mount them a different way.
Tiles as a general idea may not work out, so let's stop building ships. We'll want to use transpirational cooling or some other technique.
Stainless steel may not work out...
I understand that the argument is "Thermal protection is really difficult, so caution is warranted", but so is the rest of it. They throw their all into their current best understanding and try to make that work. They move fast and break things, and that sometimes means a lot of seeming make work (e.g. blowing up your launch site). As with all things Elon, it's a package deal; crazy rants online combined with crazy ambitious plans for the future.
Buckminster
Well-Known Member
Wasn't there some additional shielding added after a previous launch, as part of the QD/plumbing itself got damaged?
Perhaps the shielding protected those components this time, but in turn as a result of deflecting all the thrust added additional load on the supports, damaging them.
At just after 1:25 (hours:minutes) in this RGV video Ryan Hansen offers his theories about the B14.1 test tank that is currently on the OLM and how the booster catch sequence might operate. He does not think the booster will fully null out its vertical velocity and fully hover because it will be very hard to keep the booster truly vertical as the chopsticks come in and the landing rails are moved to the correct position to engage with the booster pins if the at that point the booster has zero vertical velocity.
Of course everyone outside of SpaceX is just speculating as to what will happen, and whatever the SpaceX plan is it may well change during subsequent flight tests, but Ryan does note that we cannot rely on the SpaceX-produced animation currently available to provide full details about what the plan is.
Here is a moment in his own animation showing how the landing rails, which are on the inside of the chopstick arms, are raised up when the ship pins settle onto them, and then the rail shock absorbers will absorb the weight of the booster.
Of course everyone outside of SpaceX is just speculating as to what will happen, and whatever the SpaceX plan is it may well change during subsequent flight tests, but Ryan does note that we cannot rely on the SpaceX-produced animation currently available to provide full details about what the plan is.
Here is a moment in his own animation showing how the landing rails, which are on the inside of the chopstick arms, are raised up when the ship pins settle onto them, and then the rail shock absorbers will absorb the weight of the booster.
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My expectation is that the rails will be raised long before the booster approaches. They'll leave the left arm static, bring the booster down and "lean against" it. As the booster is moving to lean against the left arm, they'll close the right arm on the booster and throttle down, allowing the lift pins to settle on the rails.
If things aren't progressing on schedule during this process, they'll throttle up and move the booster away, to be dumped in the Gulf.
I'm not sure why Ryan would doubt SpaceX's ability to hover the booster. It wants to be vertical, but it can be vertical anywhere along the length of the rails. It doesn't require pinpoint control. I wonder how much roll control they have to ensure that the lift pins are perpendicular to the rails.
I wouldn't at all be surprised to see the booster come down on the wrong side of the arms and have to be quickly dumped in the Gulf. The worst outcome would be getting the booster leaning on the left arm, being unable to complete the catch, then get hung up trying to move the booster away.
When you say "lean against", are you speculating that:
1) The left pin will settle on to the left arm, with the booster vertical?
2) The booster will literally be "leaning" (i.e.- not vertical) with the left pin on the arm, and the right pin higher?
3) The booster body will lean against the arm and then the arms slide up (or the booster settle down) on to the pins?
I assume #1, but that would raise some questions...
Number three. The goal is to eliminate variables of motion. If the booster is against the left arm, then the left arm doesn't need to move, and the booster gets a bit of stabilization from that arm. At the same time, the target position for the right arm would be known precisely.
I'd let the booster settle onto the rails instead of trying to raise the arms. Once they're up to speed on cycling boosters, they can turn the whole booster catch into one fluid motion while the booster is gently descending.
Come to think of it, a cross piece that sticks out at a 90 degree angle from the left arm would also help. The booster could nestle into the crook of the arm and that would make it very stable while closing the right arm. The one drawback to this whole leaning thing is that it produces steel-on-steel contact. If the boosters are going to be cycled many times, that's going to wear the surface of the booster. I suppose they could introduce some kind of crush barrier on the booster and/or a cushion on the arm.
As I recall, the right arm has received all the testing and hardware upgrades, so they may actually be planning to do it this way. Hopefully, we'll see in a month or so.
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