3/1832 NOTAM DetailsDisconcerting change of TFR
Isn't that just an additional backup TFR with tomorrow's still active?
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3/1832 NOTAM DetailsDisconcerting change of TFR
Yes it is. Whew. Thanks for checking. Now that you've pointed it out, there are TFRs for both Sunday and Monday. So, backups. Here's hoping that they won't be needed.Isn't that just an additional backup TFR with tomorrow's still active?
Yep, I know how it's supposed to work. Just curious as to why they haven't tested it. If it was NASA where every little thing takes a year and a billion dollars, then I get it. But it's SpaceX--stacking and test fires seem to happen almost as often as lunch.No, that has not been done. The plan is that Booster MECO (when “most engines cut off” according to SpaceX) will occur 3 seconds before the 3 Starship Raptor Vac engines ignite at which time stage separation will rapidly occur as the engine exhaust pushes against the staging ring cover and the booster decelerates and the ship accelerates as its engines throttle up.
That can only be tested in flight. If the Starship Raptor Vac engines were ignited with a Starship on a test stand with the hot staging ring under it all kinds of bad stuff would likely happen very rapidly because the staging ring would be fixed in place. The staging ring cover is likely not designed to take that kind of force. There is no reason to make it any stronger/heavier than it needs to be.
Hot ring is replacable, this flight will indicate if it is as least strong/thick enough.I would have thought they would want to test it so they could measure assumptions that the heat shield really will protect the booster, or measure exactly how much of the heat shield will be ablated so that they can make it thicker, or thinner to save weight.
65km is near vacuum, can't test that at sea level, especially with a fixed test plate. Also, what happens to ship/ test site if there is an issue?Or verify that the presence of this thing doesn't provide enough back pressure to require a change in the finicky engine startup sequence?
Thanks, all good points.65km is near vacuum, can't test that at sea level, especially with a fixed test plate. Also, what happens to ship/ test site if there is an issue?
Chamber pressure is so much higher than achievable backpressure, that shouldn't be an issue. Even flow separation is unlikely.
They may have done material tests at McGregor like with the shower plate.
I am reminded of Colin Chapman....flight will indicate if it is as least strong/thick enough
Many can built a structure that works, few can build a structure that barely works...I am reminded of Colin Chapman....
They have tested the load bearing capability with the can crusher...Yep, I know how it's supposed to work. Just curious as to why they haven't tested it. If it was NASA where every little thing takes a year and a billion dollars, then I get it. But it's SpaceX--stacking and test fires seem to happen almost as often as lunch.
I would have thought they would want to test it so they could measure assumptions that the heat shield really will protect the booster, or measure exactly how much of the heat shield will be ablated so that they can make it thicker, or thinner to save weight. Or verify that the presence of this thing doesn't provide enough back pressure to require a change in the finicky engine startup sequence?
Obviously I'm missing something: that they haven't tested it is probably a lack of interest, not lack of ability. As you point out the lit starship shouldn't be near that ring for very long, so maybe they can't do that short of a static fire? Or maybe this architecture is a one-off never to be used again and they don't care if it burns through? Or probably 100 other things I'm not thinking of.
Yah, but that was just a test of the side walls proving it can make it to stage separation...They have tested the load bearing capability with the can crusher...
Yah, but that was just a test of the side walls proving it can make it to stage separation...
(emphasis mine)Have they tested the hot staying ring at all?
Yes, but I think that was to verify that the hot staging ring could handle the compressive forces during ascent before stage sep, since it is more of a lattice structure and not a continuous piece of steel. But @TunaBug isn’t asking about that.They have tested the load bearing capability with the can crusher...
While SpaceX surely knows a great deal about the steel the ring is made from, and probably knows a great deal about how it stands up when exposed to rocket exhaust at 1ATM, as @mongo pointed out:I would have thought they would want to test it so they could measure assumptions that the heat shield really will protect the booster, or measure exactly how much of the heat shield will be ablated so that they can make it thicker, or thinner to save weight.
65km is near vacuum, can't test that at sea level, especially with a fixed test plate.
See above.Yes, but I think that was to verify that the hot staging ring could handle the compressive forces during ascent before stage sep, since it is more of a lattice structure and not a continuous piece of steel. But @TunaBug isn’t asking about that.
While SpaceX surely knows a great deal about the steel the ring is made from, and probably knows a great deal about how it stands up when exposed to rocket exhaust at 1ATM, as @mongo pointed out:
Correct. But the original question was:
(emphasis mine)
So, it was indeed a test of the hot stage ring, no?
I really meant ANY even though my examples were clearly related to blasting it with raptors. I thought I had been reading all posts about it, but I missed the crusher.But @TunaBug isn’t asking about that.
Nah, they tested the interstage function, but not the hot staging portion.Correct. But the original question was:
(emphasis mine)
So, it was indeed a test of the hot stage ring, no?
You have the first post correct, but you misstated eastern time here.First post is accurate with everything we know.
7:00am CST, 9:00am EST, 5:00am PST (20 minute window)
First post is accurate with everything we know.
7:00am CST, 9:00am EST, 5:00am PST (20 minute window)
You have the first post correct, but you misstated eastern time here.