** The Official Space Flight Thread - The Space Station and Beyond **

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Amazon's Jeff Bezos to help Nasa return to Moon

The US space agency turns to a second billionaire to help put astronauts back on the lunar surface.
www.bbc.com

I haven't had chance to watch any reviews of the NASA HLS contract decision, but my first impressions were I'm a bit sad that underperforming Blue Origin was rewarded wth the second HLS contract. I was rooting for Dynetics. I've watched Angry Astronauts factory tour with them and thought it looked likea good concept.
 
kaiowas said:
Manned Falcon 9 missions must be getting routine. 7 1/2 minutes to launch and not a single comment in here…
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Just been watching! Yes it may be verging on routine, but never gets old! The first stage boost backs to land still gives me chills! So damn impressive.
 
Armageus said:
Not seen this one posted yet, but water suppression of a single Raptor - be interesting to see the effect on 33! :D

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I am not a rocket engineer or test designer - I just like space stuff and fix planes for a living. But I cannot for the life of me see how this can do anything help with the thrust of a raptor, let alone 33 of them. The video cuts off before you can see what it’s done to the plate, but I just can’t get my head around how firing water against the exhaust flow will help anything…?
 
@Penfold101 Newton's thrid law: If two bodies exert forces on each other, these forces have the same magnitude but opposite directions - so equal and opposite reaction.

The water doesn't help the thrust of the raptor, that has already happened the force to fling the propellant out of the back of the engine at supersonic speeds has had an equal and opposite reaction on the engine pushing the rocket up. This works in space with nothing to push against.

The water plate isn't to push off it's to protect the ground from the equal and opposite reaction of super sonic high temperature gases hitting it.

I think that is the answer to your question but I apologise if I have misunderstood what you were asking.
 
Penfold101 said:
I am not a rocket engineer or test designer - I just like space stuff and fix planes for a living. But I cannot for the life of me see how this can do anything help with the thrust of a raptor, let alone 33 of them. The video cuts off before you can see what it’s done to the plate, but I just can’t get my head around how firing water against the exhaust flow will help anything…?
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Kind of confused as to why would you even think it had anything to do with it helping the thrust of the raptors. Maybe just worded wrong :p
 
TNA said:
Kind of confused as to why would you even think it had anything to do with it helping the thrust of the raptors. Maybe just worded wrong :p
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Yes, badly worded on my parts - I meant dealing with the thrust in the way of protecting the ground or diverting the exhaust away like a normal trench would, not actually help it make more thrust. When you have 33 of these making as much thrust as they do, some steel plating seems an odd way to try and protect the ground, and the water jets seem a bit pointless - there must be some idea behind it, I’ve just no idea what or why Elon didn’t wait till it was in place before trying to launch…

As an aside, water has been used on aircraft engines over the years to increase thrust - in the early days of jets water/methanol injection would be used on takeoff to give a boost in performance, and the Harrier used it in the hover to help cool the engine as airflow was massively reduced.

Can’t see that working on a rocket engine though…
 
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From what I think I've understood, the plates are there to stop the erosion of the concrete flooring, but to stop the steel plates from being damaged/melting they also will be pumping huge volumes of water through them internally. Basically a massive waterblock, whether it solves the issue?

It will also act as water delug for acoustic supression, but seemingly rather than dump the vast volumes of water from the top down, like say on the Shuttle/SLS they're combining watercooling the steel plates with deluge from below up. No idea if theis has ever been done before, so will be at least interesting to see how it plays out.

not sure about this website, but it gives a guess to how it will work at least

www.nextbigfuture.com

Renderings of the SpaceX Water Cooled Steel Plate | NextBigFuture.com

SpaceX enthusiasts have photos of all of the parts of the steel plates and pipes that will be used to make the water-cooled steel plate. Elon Musk said that
www.nextbigfuture.com www.nextbigfuture.com
 
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Armageus said:
Not seen this one posted yet, but water suppression of a single Raptor - be interesting to see the effect on 33! :D

Click to expand...
The test went on for about 13 seconds. Does anyone remember how long it took for starship to fire up all engines and get off the ground?

Judging by what I can see at the start of the video (fine soil and sediment that looks likes it has been disturbed around the steel plate. In an arc away from the engine), this doesn't seem like the first test. I wonder if they have been looking into how much water they need for this? Or maybe testing the durability of the solution for repeated launches?
 
VaderDSL said:
From what I think I've understood, the plates are there to stop the erosion of the concrete flooring, but to stop the steel plates from being damaged/melting they also will be pumping huge volumes of water through them internally. Basically a massive waterblock, whether it solves the issue?

It will also act as water delug for acoustic supression, but seemingly rather than dump the vast volumes of water from the top down, like say on the Shuttle/SLS they're combining watercooling the steel plates with deluge from below up. No idea if theis has ever been done before, so will be at least interesting to see how it plays out.

not sure about this website, but it gives a guess to how it will work at least

www.nextbigfuture.com

Renderings of the SpaceX Water Cooled Steel Plate | NextBigFuture.com

SpaceX enthusiasts have photos of all of the parts of the steel plates and pipes that will be used to make the water-cooled steel plate. Elon Musk said that
www.nextbigfuture.com www.nextbigfuture.com
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That is for 1 raptor, we've no idea at what power setting the raptor was at and still the water flow at the end was no where near what it was before the raptor started up. Now add 32 more for much longer if launch 1 is anything to go by. Where is all this water coming from? They can't use salt water from the sea, they don't have any gravity feed tanks built and they'd need at least 2 the size of the ones at launch pad 39 at Kennedy Space Centre to feed that plate

NASA%E2%80%99s_SLS_and_SpaceX%E2%80%99s_Falcon_9_at_Launch_Complex_39A_%26_39B_%28KSC-20220406-PH-JBP01-0001%29.jpg


Any water they use can't flow into the nature reserve which means it all has to be caught and pumped into settling ponds, ponds they don't have. There are far more questions than answers for this steel plate idea.

Common Sense Skeptic talks about this steel plate idea in this video. It starts when they talk about it.

 
Colonel_Klinck said:
They can't use salt water from the sea, they don't have any gravity feed tanks built and they'd need at least 2 the size of the ones at launch pad 39 at Kennedy Space Centre to feed that plate
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It's likely not going to be gravity fed, but using tanks of pressurised gas, very similar to SLC 40

SpaceX Texas launch site Discussion and Updates - Thread 12

SpaceX Texas launch site Discussion and Updates - Thread 12
forum.nasaspaceflight.com forum.nasaspaceflight.com



Also tanks now being transported:

SpaceX Texas launch site Discussion and Updates - Thread 12

SpaceX Texas launch site Discussion and Updates - Thread 12
forum.nasaspaceflight.com forum.nasaspaceflight.com
 
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Armageus said:
It's likely not going to be gravity fed, but using tanks of pressurised gas, very similar to SLC 40

SpaceX Texas launch site Discussion and Updates - Thread 12

SpaceX Texas launch site Discussion and Updates - Thread 12
forum.nasaspaceflight.com forum.nasaspaceflight.com



Also tanks now being transported:

SpaceX Texas launch site Discussion and Updates - Thread 12

SpaceX Texas launch site Discussion and Updates - Thread 12
forum.nasaspaceflight.com forum.nasaspaceflight.com
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That still doesn't answer how they are going to contain all that water at launch and what they are going to do with it immediately after the launch. The nature reserve is so close to the site. FAA and SpaceX are now being sued due to the lack of a proper environmental assessment being carried out. Can't see any more launches until that works its way through the courts and they some how deal with all these risks to the nature reserve.

boco-1.png
 
Colonel_Klinck said:
Common Sense Skeptic talks about this steel plate idea in this video. It starts when they talk about it.

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If you watch the twitter link that Armageus posted you can clearly see that the system they are testing does not work like CSS predicts in his video. And by predicts I mean he uses some random guys model he found on the internet.

The most obvious reason that I can see for why the water needs to be the same(or close) pressure as the engine exhaust, is to enable the water to continue to flow when the engines are ignited otherwise the exhaust gases would enter into the hole and you would have a build up of pressure within the steel sandwich and a total loss of cooling from the water. It also prevents the plates from buckling inwards as the exhaust gases exert a pressure on the top layer. I don't think they are actually using the water to push the exhaust gases back (technically that isn't what Elon said).

I feel as if the failure mode of the concrete was due to the extreme heat weakening the concrete and causing it to disintegrate (May have involved water within the structure boiling off and cracking the structure) not purely an issue of the force applied by the exhaust. This is why they are trying to cool the steel plate down.

I did some quick maths.
Raptor is the Thrust of a single raptor engine.
Diameter is the outer diameter of Starship



Pressure from the exhaust is 1,369,439 Pa. From a link I found the compressive strength of the Fondag is 25,000,000 Pa at 1,100 deg C.

Force doesn't seem to be the issue, cooling appears to be the real challenge. Kind of strange that CSS didn't do this maths in his video.

I have no idea, where he got the idea from that they straightened the rebar, I remember seeing a picture maybe posted here where people thought they could see the cut out rebar. Also this guy really tried to suggest that Elon Musk launched Starship to coincide with Hitler's birthday :rolleyes: . At least the 4/20 blaze it was a more believable take.


The only thing in that section that is of any interest is the need for a run off pond.
 
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Chuk_Chuk said:
If you watch the twitter link that Armageus posted you can clearly see that the system they are testing does not work like CSS predicts in his video. And by predicts I mean he uses some random guys model he found on the internet.

The most obvious reason that I can see for why the water needs to be the same(or close) pressure as the engine exhaust, is to enable the water to continue to flow when the engines are ignited otherwise the exhaust gases would enter into the hole and you would have a build up of pressure within the steel sandwich and a total loss of cooling from the water. It also prevents the plates from buckling inwards as the exhaust gases exert a pressure on the top layer. I don't think they are actually using the water to push the exhaust gases back (technically that isn't what Elon said).
Click to expand...

It needs to be able to flow against the pressure of the thrust from the engines. If water isn't flowing out and evaporating then it can't cool the steel plate and it will buckle/burn through in no time. If it does buckle/rupture then there will be a loss of pressure and the whole thing fails. You'll end upo with steel plates doing a flying concrete impression.

As for the random guy, I'm fairly certain that is the 3D modeller that Everyday Astronaut, Scott Manley, Marcus House etc all use in their videos.

Chuk_Chuk said:
I feel as if the failure mode of the concrete was due to the extreme heat weakening the concrete and causing it to disintegrate (May have involved water within the structure boiling off and cracking the structure) not purely an issue of the force applied by the exhaust. This is why they are trying to cool the steel plate down.

I did some quick maths.
Raptor is the Thrust of a single raptor engine.
Diameter is the outer diameter of Starship



Pressure from the exhaust is 1,369,439 Pa. From a link I found the compressive strength of the Fondag is 25,000,000 Pa at 1,100 deg C.

Force doesn't seem to be the issue, cooling appears to be the real challenge. Kind of strange that CSS didn't do this maths in his video.

I have no idea, where he got the idea from that they straightened the rebar, I remember seeing a picture maybe posted here where people thought they could see the cut out rebar. Also this guy really tried to suggest that Elon Musk launched Starship to coincide with Hitler's birthday :rolleyes: . At least the 4/20 blaze it was a more believable take.


The only thing in that section that is of any interest is the need for a run off pond.
Click to expand...

From what I have read it is likely water trapped in the concrete boiling and cracking the concrete, then gases get in those cracks and the next thing you have is concrete flying hundreds of meters in the air. Its why large rockets have a flame trench and water deluge systems. You divert the gasses/heat away with the slope while the water cools the gasses and carries that heat away as stream. If the steel plate fails you will likely end up with flying concrete again after the steel plates fly.

I don't think he meant they are reusing all the rebar, just some of it. I also heard that on another video, maybe Scott Manley :confused:

Where did he suggest Hitler's birthday? I heard him suggest its the national weed day.
 
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